Biomedical subjects

K L Goa

Publications and source records attributed to K L Goa.

At least 91 records · Page 5Linked to original sources

PubMed1997

Toremifene. A review of its pharmacological properties and clinical efficacy in the management of advanced breast cancer.

The triphenylethylene antiestrogen toremifene is a chlorinated derivative of the antiestrogen tamoxifen, an agent which has been widely and successfully used in the treatment of breast cancer. Clinical trials investigating the efficacy of toremifene as first-line endocrine therapy in postmenopausal women with advanced breast cancer (estrogen receptor status positive or unknown) have shown this drug to have similar antitumour activity to that of tamoxifen. In multicentre comparative trials, objective responses (complete and partial) occurred in 20 to 29% of patients treated with toremifene (60 to 240 mg/day) and in 19 to 37.5% of tamoxifen (20 or 40 mg/day) recipients. The duration of response, time to disease progression and median overall survival time were generally similar in both treatment groups. Toremifene is well tolerated. Most drug-related adverse effects are mild or moderate in severity and rarely necessitate discontinuation of therapy. The tolerability profile of toremifene is similar to that reported for tamoxifen, the most common adverse effects being hot flushes, sweating, nausea and/or vomiting, dizziness, oedema, and vaginal discharge and/or bleeding. Thus, toremifene provides an equally effective and well tolerated alternative to tamoxifen for the first-line endocrine therapy of postmenopausal advanced breast cancer. Preclinical studies showing toremifene to have a lower carcinogenic potential than tamoxifen indicate that toremifene may be a preferable agent for long term treatment regimens; however, these findings require confirmation in the clinical setting.

Animals↗

PubMed1997

Dolasetron. A review of its pharmacology and therapeutic potential in the management of nausea and vomiting induced by chemotherapy, radiotherapy or surgery.

Dolasetron (dolasetron mesilate) is a pseudopelletierine-derived 5-HT3 antagonist which has recently become available for clinical use. It is rapidly converted in vivo to its active major metabolite, hydrodolasetron, which appears to be largely responsible for its pharmacological activity. In clinical trials, single intravenous or oral doses of dolasetron were effective in preventing acute chemotherapy-induced nausea and vomiting (CINV). Intravenous doses of 1.8 mg/kg achieved complete suppression of vomiting in approximately 50% of patients receiving highly emetogenic cisplatin-containing chemotherapy and in approximately 60 to 80% of patients receiving moderately emetogenic chemotherapy. In the latter setting, oral doses of 200 mg achieved similar response rates. In comparative studies, intravenous dolasetron 1.8 mg/kg was as effective as intravenous granisetron 3 mg or ondansetron 32 mg after highly emetogenic chemotherapy, and oral dolasetron 200 mg was equivalent to multiple oral doses of ondansetron (3 or 4 doses of 8 mg) after moderately emetogenic chemotherapy. Dolasetron 1.8 mg/kg was superior to metoclopramide in preventing emesis induced by high dose cisplatin or by moderately emetogenic chemotherapy in high risk subgroups. Dolasetron has also shown efficacy in preventing radiotherapy-induced nausea and vomiting (RINV) in preliminary studies. Single intravenous or oral dolasetron doses ranging from 12.5 to 100 mg and 25 to 200 mg, respectively, were significantly more effective than placebo in preventing postoperative nausea and vomiting (PONV) in female surgical patients. A 50 mg intravenous dose was as effective in preventing PONV as ondansetron 4 mg in a mixed-gender group. Intravenously administered dolasetron was also effective in treating established PONV, although complete suppression of vomiting was achieved in < 40% of patients. Dolasetron has a tolerability profile characteristic of this class of compounds, with headache, dizziness and diarrhoea being the most commonly occurring adverse events in clinical trials. Diarrhoea is not thought to be related to dolasetron administration, being experienced mostly by patients receiving chemotherapy. Dolasetron and other 5-HT3 receptor antagonists have been associated with minor changes in ECG intervals, but these generally do not appear to be clinically important. Thus, available evidence suggests that dolasetron will provide an alternative to other 5-HT3 receptor antagonists for the management of CINV and PONV. Further studies are required to determine whether it offers any advantages over other agents in these settings and to determine the optimum dosage for preventing RINV.

Administration, Oral↗

PubMed1997

Valsartan. A review of its pharmacology and therapeutic use in essential hypertension.

Valsartan competitively and selectively inhibits the actions of angiotensin II at the AT1 receptor subtype which is responsible for most of the known effects of angiotensin II. In clinical trials in patients with mild to moderate essential hypertension valsartan was as effective as losartan, lisinopril, enalapril, amlodipine and hydrochlorothiazide. Addition of the latter reduced blood pressure in patients who did not respond sufficiently to valsartan monotherapy. Preliminary data also suggest valsartan may be effective in patients with severe essential hypertension. The drug was as effective as lisinopril as treatment for mild to moderate essential hypertension in patients with renal insufficiency and did not worsen renal function. Headache, dizziness and fatigue were the most common adverse events in placebo-controlled studies; the incidence of these adverse events was not significantly different between placebo and valsartan recipients. Compared with ACE inhibitors, valsartan was associated with a significantly lower incidence of dry cough. Thus, valsartan is an effective treatment for mild to moderate essential hypertension and may be particularly useful in patients who experience persistent cough during ACE inhibitor therapy.

Antihypertensive Agents↗

PubMed1997

Gemcitabine. A review of its pharmacology and clinical potential in non-small cell lung cancer and pancreatic cancer.

Gemcitabine [2'-deoxy-2',2'-difluorocytidine monohydrochloride (beta isomer); dFdC] is a novel deoxycytidine analogue which was originally investigated for its antiviral effects but has since been developed as an anticancer therapy. Gemcitabine monotherapy produced an objective tumour response in 18 to 26% of patients with advanced non-small cell lung cancer (NSCLC) and appears to have similar efficacy to cisplatin plus etoposide. Objective response rates ranging from 26 to 54% were recorded when gemcitabine was combined with cisplatin, and 1-year survival duration after such treatment ranged from 35 to 61%. Improvements in a range of NSCLC disease symptoms and/or in general performance status occurred in many patients who received gemcitabine, with or without cisplatin, in 3 clinical trials. Gemcitabine appears to be cost effective compared with best supportive care for NSCLC. In addition, direct costs associated with administration of gemcitabine monotherapy may be lower than those for some other NSCLC chemotherapy options, according to retrospective cost-minimisation analyses. The combination of gemcitabine plus cisplatin was associated with a lower cost per tumour response than cisplatin plus etoposide or cisplatin plus vinorelbine, according to a retrospective cost-effectiveness analysis. In a single comparative study in patients with advanced pancreatic cancer, gemcitabine was more effective than fluorouracil with respect to survival duration and general clinical status. It also showed modest antitumour and palliative efficacy in patients refractory to fluorouracil. Gemcitabine appears to be well tolerated, although further comparisons with other chemotherapy regimens are required. The available data indicate that gemcitabine monotherapy is better tolerated than cisplatin plus etoposide in patients with NSCLC. Data from noncomparative studies suggest that the combination of gemcitabine and cisplatin has an acceptable tolerabilty profile. In a single trial in patients with pancreatic cancer, fluorouracil was better tolerated than gemcitabine; however, gemcitabine was generally well tolerated overall in this study. Thus, gemcitabine (with or without cisplatin) may prove attractive to patients with advanced NSCLC, given their limited life expectancy and the toxicity associated with many other chemotherapy regimens. More detailed characterisation of its risk-benefit profile compared with those of current and developing regimens for NSCLC should be possible once results from several ongoing studies are available. Gemcitabine is a valuable new chemotherapy option for patients with advanced pancreatic cancer, a disease considered incurable at present. Its apparent survival and palliative benefits over fluorouracil require confirmation, but are encouraging, as the need to improve both the duration and quality of survival in these patients is well recognised.

Animals↗

PubMed1997

Tacrolimus. An update of its pharmacology and clinical efficacy in the management of organ transplantation.

Tacrolimus (FK 506) has been evaluated as immunosuppressive therapy in patients with a variety of solid organ and other transplants. Extensive data have now confirmed its efficacy as primary or rescue therapy in renal and hepatic transplantation. In prospective and historically controlled studies of primary therapy, tacrolimus generally demonstrated greater efficacy than the conventional formulation of cyclosporin for preventing episodes of acute rejection and allowed reduction of corticosteroid use. Chronic rejection rates were also significantly lower with tacrolimus in a large randomised liver transplantation trial. However, patient and graft survival rates were similar in both treatment groups (although numerically larger in adults with liver transplants). In children, rejection rates and corticosteroid requirements were usually lower with tacrolimus and patient and graft survival were generally similar with the 2 immunosuppressants. The finding of reduced corticosteroid requirements with tacrolimus may be of particular benefit in prepubertal children, who are still growing. A small amount of evidence has also accumulated regarding the use of tacrolimus as primary therapy in patients who have undergone bone marrow or heart and/or lung transplantation. Data are not conclusive, particularly in children, but tacrolimus appears to be useful for treating patients who have undergone these organ transplantations and may be associated with a lower incidence of obliterative bronchiolitis than cyclosporin in the latter group. Potential efficacy has also been shown in a limited number of patients with pancreas or pancreas-kidney, pancreatic islet and intestinal or multivisceral transplants, and in children who have undergone heart or heart-lung transplantation. Tacrolimus also has a use as rescue therapy in bone marrow, heart, lung and pancreatic transplantation, but data are currently insufficient for conclusions to be made. However, these results support the need for further study in these populations. Adverse effects occurring during tacrolimus therapy are generally of the type common to all immunosuppressive regimens. However, diabetes mellitus, neurotoxicity and nephrotoxicity are more common in tacrolimus than cyclosporin recipients. Hyperlipidaemia, hypertension, hirsutism and gingival hyperplasia are more common with cyclosporin. In 2 large multicentre clinical trials (US liver and European renal), tacrolimus was discontinued more frequently during the first year because of adverse events. However, the tolerability of tacrolimus appears related to dosage, improving as the dose is reduced. Tacrolimus should be considered an effective primary immunosuppressant in renal and hepatic transplantation. The drug is also a useful agent for rescue therapy in patients experiencing rejection or poor tolerability to cyclosporin. Thus, tacrolimus provides the clinician with an effective option for patients requiring immunosuppression and, with a different tolerability and efficacy profile to cyclosporin, it will better allow the tailoring of therapy to meet the needs of individual patients.

Graft vs Host Disease↗

PubMed1997

Simvastatin. A reappraisal of its cost effectiveness in dyslipidaemia and coronary heart disease.

The Scandinavian Simvastatin Survival Study (4S) has confirmed the link between the cholesterol-reducing effects of simvastatin and improved survival in patients with hypercholesterolaemia and pre-existing coronary heart disease (CHD). Pharmacoeconomic analyses of the 4S trial, using prospectively collected data for cost-generating events, demonstrate that the cost per year of life saved for simvastatin in such patients falls within the range considered cost effective. Reductions in resource utilisation costs (numbers of hospitalisations and revascularisation procedures) largely offset the acquisition cost of long term simvastatin treatment in the US. Models of primary prevention incorporating epidemiological data to predict CHD events generally suffer from deficiencies in the methods and assumptions used, and no firm conclusions can be made at present regarding relative cost effectiveness of the drugs studied, including simvastatin. It is generally agreed that cost effectiveness will improve in patients with higher absolute risk of CHD. In summary, simvastatin has been shown in a major clinical trial and its companion economic analyses to reduce mortality and to be cost effective in patients with hypercholesterolaemia and existing CHD. As is the case for others of its class, its cost-effectiveness ratio in primary prevention remains to be ascertained. This issue aside, simvastatin is a rational choice of cholesterol-lowering agent in secondary prevention whose use can be justified on an economic basis.

Coronary Disease↗

PubMed1997

Terazosin. A pharmacoeconomic evaluation of its use in benign prostatic hyperplasia.

Benign prostatic hyperplasia (BPH) is a common disorder in elderly men which carries a substantial economic burden. Urinary symptoms associated with moderate to severe disease can significantly interfere with daily activities and reduce quality of life. Obstruction of urine flow in men with BPH can result from nonmalignant enlargement of the prostate gland (static component of BPH) and from alpha 1 receptor-mediated increased smooth muscle tone of the bladder neck and prostate (dynamic component of BPH). Transurethral resection of the prostate (TURP) is generally very effective and has traditionally been the standard treatment for men with moderate to severe BPH. However, response to therapy with TURP is not universal and the procedure is associated with a number of potential complications. Moreover, many men prefer to avoid or are not suitable candidates for this invasive procedure. Thus, there is an increasing role for less invasive treatment, including drug therapy, in men with moderate to severe BPH. Terazosin is an alpha 1 receptor antagonist which has been shown in placebo-controlled trials to significantly improve American Urology Association (AUA) symptom and quality-of-life scores and symptom problem index ('bother' score), as well as increase peak urinary flow rate, in men with BPH. In a recent large randomised US trial, treatment for 1 year with terazosin titrated to 10 mg/day improved mean AUA symptom score and peak urinary flow rate to a significantly greater extent than finasteride 5 mg/day in men with moderate to severe BPH. The most frequently reported adverse events associated with terazosin include dizziness, asthenia, postural hypotension, somnolence, headache, peripheral oedema, nasal congestion/rhinitis and syncope. Approximately 5% of men with BPH discontinue terazosin because of adverse events. Results of an economic evaluation of terazosin, in which both clinical and economic data were collected prospectively in a randomised placebo-controlled study design, showed similar total direct treatment costs per 1000 patients associated with 1 year of therapy with terazosin ($US3.57 million) and placebo ($US3.78 million) in men with moderate to severe BPH (1992 dollars). The analysis, which was conducted from the perspective of a managed care organisation in the US, demonstrated that the lower medication costs in the placebo group relative to the terazosin group were offset by increased inpatient care costs. Thus, terazosin (titrated to response up to a maximum of 10 mg/day) was significantly more effective than placebo in improving disease-specific symptoms and quality of life, but at a similar overall cost to placebo. Another economic analysis, also conducted from a third-party payer perspective in the US, modelled direct treatment costs associated with terazosin, finasteride and TURP during the first 2 years after initiating therapy in men with moderate to severe BPH. Results of the study favoured terazosin; the private insurance cost per patient undergoing primary treatment with TURP was $US6411, compared with $US2860 with finasteride (45% of the cost of TURP) and $US2422 with terazosin (38% of the cost of TURP). Medicare costs were lower for all 3 treatment groups but the relative comparisons were similar; corresponding costs per patient were $US3874, $US2161 and $US1820 (1992 dollars). A companion break-even cost analysis used a hypothetical cohort of men with BPH starting treatment at age 67 years. Private insurance costs associated with terazosin remained lower then those associated with TURP for approximately 15 years (the corresponding break-even point was 10 years for finasteride vs TRUP). Medicare costs associated with terazosin would not exceed those of TURP for approximately 7 years (5.5 years for finasteride vs TURP). In conclusion, a limited number of detailed pharmacoeconomic analysis of terazosin have been conducted to date, although it has not been compared with other a1 receptor antagonists.

Adrenergic alpha-Antagonists↗

PubMed1997

Dornase alfa. A review of pharmacoeconomic and quality-of-life aspects of its use in cystic fibrosis.

Cystic fibrosis (CF) is a fatal hereditary disease; patients with CF have an average lifespan of 30 years. By cleaving neutrophil-derived DNA, dornase alfa (recombinant human deoxyribonuclease I) decreases the adhesiveness and visco-elasticity of sputum in the infected lungs of patients with CF. As a result, respiratory function is improved in patients with all degrees of disease severity, and the relative risk of pulmonary exacerbations is reduced in patients with mild to moderate disease. Resource utilisation (days spent in hospital or receiving parenteral antibiotics) in patients with mild to moderate disease is also reduced by dornase alfa, as evidenced by a placebo-controlled trial in > 900 patients. Cost savings generated by these reductions in resource use during 24 weeks of dornase alfa therapy offset about 17 to 37.5% of the acquisition cost of the drug, depending on local cost data for various countries. Reductions in resource utilisation with dornase alfa have not been observed in patients with severe disease. Available cost-effectiveness and cost-utility analyses are not fully published. One analysis estimated that the incremental cost of avoiding one hospitalisation was about $Can 15,000 relative to standard therapy after 1 year of treatment. Informal analysis in the UK suggests a cost per quality-adjusted life-year of 25,000 Pounds for dornase alfa. Some quality-of-life (QOL) domains (mainly cough frequency and chest congestion) have shown modest improvement in patients treated with dornase alfa, mainly those with mild CF. Persuasive evidence of QOL benefit is lacking in those with more severe disease. Identifying patients most likely to benefit from dornase alfa therapy is essential to maximise clinical and cost benefits. The lack of a demonstrated reduction in resource utilisation in patients with severe CF makes its use more difficult to justify economically in this group than in those with less severe disease. However, in the absence of other treatments for this group, economic considerations must be weighed against clinical benefits. In conclusion, the acquisition cost of dornase alfa is partially offset by savings gained by reducing resource utilisation in patients with mild to moderate CF, and the drug appears to improve quality of life in some patients, mostly those with less severe disease. However, in the absence of guidance from definitive cost-effectiveness analyses, individual healthcare providers must make their own decisions about how best to provide dornase alfa to patients with CF in a rational and cost-justifiable manner.

Cystic Fibrosis↗

PubMed1996

Ticlopidine. A review of its pharmacology, clinical efficacy and tolerability in the prevention of cerebral ischaemia and stroke.

Ticlopidine is a thienopyridine derivative which reduces the risk of reversible ischaemia and stroke in patients who have previously experienced a cerebral ischaemic episode. In comparison with aspirin, ticlopidine produced a significant reduction in the risk of stroke in a multicentre clinical trial involving more than 3000 patients with previous transient or persistent minor ischaemia, and was superior to placebo for the prevention of stroke recurrence in more than 1000 patients who had experienced a major thrombotic stroke. The cost-utility ratio for ticlopidine in comparison with aspirin was estimated to be $US31 200 to 55,000 per quality-adjusted life-year gained. Diarrhoea is the most common adverse event in ticlopidine recipients (20 to 22% incidence versus about 10% with placebo), although skin rash, nausea, dyspepsia, bleeding events, abnormal liver function and haematological disturbances were also observed in clinical trials. Severe neutropenia is the most serious event: this developed in 0.85% of patients receiving ticlopidine in 2 large clinical studies (n = 4098) but resolved after treatment withdrawal. Fatal neutropenia, although rare, has been reported in some patients receiving ticlopidine. Thus, ticlopidine is effective in reducing the risk of recurrent cerebral ischaemia and stroke. It appears to provide a gain over aspirin for the prevention of stroke after reversible ischaemia, particularly during the first year of treatment (when the risk of stroke is greatest), although further data on its absolute relative benefit would be useful. The extent to which ticlopidine is prescribed will probably depend on individual clinicians' perception of its risk/benefit and cost-effectiveness profiles. Ticlopidine is likely to be particularly useful for stroke prophylaxis in patients who do not tolerate aspirin or who have an ischaemic episode during aspirin treatment, and for the prevention of stroke recurrence in patients who have previously experienced a major stroke.

Brain Ischemia↗

PubMed1996

Mitoxantrone: a review of its pharmacological properties and use in acute nonlymphoblastic leukaemia.

Acute nonlymphoblastic leukaemia (ANLL) is a malignant condition strongly associated with advancing age. Of adult acute leukaemias, 80 to 85% are classified as ANLL, with more than half of all patients being aged over 60 years. Although advancing age has been reported to be a poor prognostic factor in ANLL, recent clinical trials have shown good results in patients aged 60 years and over after coadministration of the anthracenedione antineoplastic agent mitoxantrone with cytarabine. In 1 study in particular, which involved patients aged 60 to 81 years, no correlation was found between increasing age and response rate. However results of a major clinical trial showed age greater than 60 years to be associated with poorer outcomes. Mitoxantrone as initial induction treatment is at least as effective as daunorubicin when either drug is given in combination with cytarabine to patients with previously untreated ANLL. Complete response rates in randomised comparative trials were 53 to 67% after mitoxantrone with cytarabine and 37 to 70% after daunorubicin with cytarabine. In a major US study, significantly more patients achieved a complete response after 1 treatment cycle of mitoxantrone and cytarabine than after daunorubicin and cytarabine. Mitoxantrone has also been effective in inducing complete remissions in patients with relapsed or refractory ANLL, mainly in combination with other antineoplastic agents. Overall survival appears similar after treatment with regimens containing either mitoxantrone or daunorubicin in patients with ANLL, although there have been reports of trends towards increased survival rates with mitoxantrone. The incidence of cardiotoxicity appears low in patients with ANLL who have received mitoxantrone. Lower cardiotoxicity of mitoxantrone relative to daunorubicin has not been conclusively demonstrated in patients with ANLL, although trials in patients with breast cancer have shown mitoxantrone to cause fewer cardiac adverse effects than doxorubicin. This is of particular interest in the elderly, as this group of patients is especially susceptible to the effects of anthracycline-induced cardiac toxicity. Thus, mitoxantrone is a suitable first-line agent for the induction of remission in patients with ANLL, with clearly demonstrated efficacy in patients aged 60 years and over.

Adult↗

PubMed1996

Formestane. A review of its pharmacological properties and clinical efficacy in the treatment of postmenopausal breast cancer.

Formestane (4-hydroxyandrostenedione) is an aromatase inhibitor which significantly reduces plasma levels of estrogen and has shown antitumour activity in postmenopausal women with breast cancer. Objective response rates in heavily pretreated patients with advanced breast cancer generally range between 20 and 30% during treatment with intramuscular formestone 250 or 500mg once every 2 weeks, and a further 20 to 30% of patients experience disease stabilisation. The median duration of response is between 8 and 14 months. Highest response rates are observed in soft tissue metastases, in patients with estrogen-responsive tumours and in those showing a response to previous endocrine therapy. Furthermore, there is some evidence to suggest that higher response rates are achieved with formestane 500 versus 250mg once every 2 weeks. In comparative studies, the clinical efficacy of intramuscular formestane 250mg did not differ significantly from that of oral megestrol when administered as second-line endocrine therapy to patients with advanced disease in whom previous tamoxifen therapy had failed. In addition, formestane produced a response rate, duration of response and overall survival rate that was not significantly different from that of oral tamoxifen when administered as first-line endocrine therapy to patients with advanced disease, but tamoxifen was superior in some measures. Further investigation of these 2 agents, including the higher dosage of formestane (500mg), is necessary to confirm their relative efficacies. Formestane is well tolerated by the majority of patients; adverse events rarely necessitate cessation of therapy. The most common adverse events are local reactions at the injection site and systemic events usually related to the effect of the drug on the hormonal milieu. The systemic tolerability of formestane is similar to that of tamoxifen but better than that of megestrol. Thus, formestane is effective and well tolerated as first-line endocrine therapy for advanced disease. However, at present, it is unlikely to challenge tamoxifen in this indication, based on recent findings from a large comparative study and the fact that formestane requires intramuscular administration. Nonetheless, formestane, which appears to have a better tolerability profile than other currently available second-line agents (including megestrol and the aromatase inhibitor aminoglutethimide), is a valuable drug for the second-line treatment of postmenopausal women with advanced breast cancer.

Androstenedione↗

PubMed1996

Itraconazole. A reappraisal of its pharmacological properties and therapeutic use in the management of superficial fungal infections.

Itraconazole is an orally administered triazole antifungal agent. Its spectrum of activity includes dermatophyte, dimorphic and dematiaceous fungi, yeasts, and some moulds. In clinical trials, mycological cure was attained in approximately 70 to 80, > or = 70 and > or = 80% of patients with, respectively, fingernail and toenail onychomycosis (200 mg/day for 3 months), dermatophytosis (100 mg/day for 2 to 4 weeks) and vaginal candidiasis (400 mg/day for 1 day or 200 mg/day for 3 days). Approximately 20 to 30% of patients with onychomycosis may relapse after completion of therapy; relapse rate data are limited for the other indications. Recently developed intermittent regimens of itraconazole (400 mg/day for 1 week per month for 3 to 4 months) appear to have similar efficacy to standard regimens in the treatment of onychomycosis. Shorter, higher dosage itraconazole treatment regimens (200 or 400 mg/day for 1 week) are also beneficial in dermatomycoses. Discrepancies and limitations of study design hamper conclusions about efficacy relative to other antifungal drugs. Newer intermittent and short course higher dosage itraconazole regimens have also not been evaluated in comparative studies. Available studies show that the efficacy of itraconazole appears to be greater than that of griseofulvin, but similar to or lower than that of terbinafine in patients with dermatophyte onychomycosis or cutaneous fungal infections. Moreover, the efficacy of itraconazole may be similar to or lower than that of fluconazole in the treatment of cutaneous mycoses. Comparative data from patients with acute vaginal candidiasis suggest that itraconazole is at least as effective as intravaginal clotrimazole and oral fluconazole, and superior to intravaginal econazole. These results require confirmation. Prescription-event monitoring data indicate that itraconazole is generally well tolerated. Gastrointestinal disturbances, dizziness and headache occur most commonly; liver toxicity has been rarely described. Its usefulness in some clinical situations may be limited because of its ability to interact with various therapeutic agents. In conclusion, itraconazole along with other established agents should be considered a first-line treatment for patients with extensive or recalcitrant cutaneous fungal infections, mixed dermatophyte and Candida onychomycosis or vaginal candidiasis. It is currently considered a second-line drug for dermatophyte onychomycosis; the use of newer intermittent itraconazole treatment regimens may, however, extend its role in the management of this condition. Although itraconazole offers greater benefit than conventional therapies (griseofulvin and ketoconazole) in terms of efficacy and tolerability, wider clinical experience is required to determine its merits relative to the newer agents, terbinafine and fluconazole.

Absorption↗

PubMed1996

Sevoflurane. A review of its pharmacodynamic and pharmacokinetic properties and its clinical use in general anaesthesia.

Sevoflurane is an ether inhalation general anaesthetic agent with lower solubility in blood than isoflurane or halothane but not desflurane. The low solubility and the absence of pungency facilitate rapid mask induction; the low blood solubility also expedites "wash-out' and therefore recovery from anaesthesia. Sevoflurane produces dose-dependent CNS, cardiovascular and respiratory depressant effects that generally parallel those of isoflurane. Sevoflurane is degraded by carbon dioxide absorbents to nephrontoxic (in rats) haloalkenes, although renal toxicity has not been observed in humans. Compared with other inhalation anaesthetics, negligible quantities of carbon monoxide are generated from degradation of sevoflurane by carbon dioxide absorbents. Sevoflurane has negligible airway irritant effects, which facilitates a "smooth' induction, even in comparison with halothane in paediatric patients, and makes sevoflurane especially amenable to rapid induction of anaesthesia in adults and children. Emergence, orientation an postoperative cognitive and psychomotor function recovery of paediatric outpatients is singnificantly more rapid from sevoflurane than from halothane anaesthesia. In adult inpatients and outpatients, emergence and orientation are significantly faster after sevoflurane than after isoflurane but not desflurane anaesthesia. Other recovery parameters (e.g. times to sitting, ambulation) occur at similar times after either sevoflurane or desflurane anaesthesia. Recovery of psychomotor function occurs at generally similar times after sevoflurane, isoflurane or desflurane. Compared with propofol, sevoflurane facilitates more predictable extubation times and significantly better postoperative modified Aldrete scores in outpatients, although cognitive and psychomotor recovery occurs at similar times for both agents. As a supplement to opioid anaesthesia during coronary bypass graft surgery or in those at risk for myocardial ischaemia, sevoflurane is comparable to isoflurane. Limited data suggest that it is also as useful as isoflurane for the maintenance of anaesthesia during neurosurgical or obstetric procedures. Sevoflurane is well tolerated by adult and paediatric patients during induction of anaesthesia, with a low incidence of mild airway complications (breath-holding, coughing, excitement and laryngospasm). During rapid induction, it is particularly better tolerated than isoflurane or halothane. Sevoflurane has a lower potential for hepatic injury than halothane. Unlike methoxyflurane, sevoflurane undergoes minimal intrarenal defluorination, which may account for the lack of fluoride ion-induced nephrotoxicity in humans, despite elevated plasma fluoride levels after its use. In summary, sevoflurane provides for a rapid and smooth induction of, and recovery from, anaesthesia. These features combined with its favourable cardiovascular profile should make sevoflurane the agent of choice for inhalation induction in adult and paediatric anaesthesia. Although further clinical evaluation will define the role of this agent relative to that of propofol and desflurane, sevoflurane should also prove to be a valuable alternative anaesthetic agent for adults in both outpatient and inpatient surgery.

Adolescent↗

PubMed1996

Losartan potassium: a review of its pharmacology, clinical efficacy and tolerability in the management of hypertension.

Losartan potassium is an orally active, nonpeptide angiotensin II (AII) receptor antagonist. It is the first of a new class of drugs to be introduced for clinical use in hypertension. This novel agent binds competitively and selectively to the AII subtype 1 (AT(1)) receptor, thereby blocking AII-induced physiological effects. An active metabolite, E3174, contributes substantially to its antihypertensive effect, which persists throughout 24 hours after once-daily administration. In patients with mild to moderate hypertension, losartan potassium 50 to 100mg once daily as monotherapy lowers blood pressure to a similar degree to enalapril, atenolol and felodipine extended release (ER). Losartan potassium combined with hydrochlorothiazide reduces blood pressure further than either drug given separately. About one-third of patients with severe hypertension have responded to the combination product. Losartan potassium appears to be effective in elderly patients. Losartan potassium is very well tolerated. In clinical trials, dizziness was the only drug-related event reported more frequently with losartan potassium monotherapy than with placebo. First-dose hypotension is uncommon. An aspect of the drug's tolerability profile which may prove to be particularly advantageous is that it is associated with a similar incidence of cough to placebo in patients with a history of ACE inhibitor-related cough. Additionally, clinically relevant adverse metabolic effects or laboratory abnormalities have not been documented during losartan potassium therapy and renal function is preserved in patients with or without renal insufficiency. The adverse effect profile of the losartan potassium-hydrochlorothiazide combination resembles those for losartan potassium monotherapy and placebo. Long term tolerability data are limited (<2 years) but support the very good tolerability profile in shorter studies. Elements of the drug's profile yet to be assessed or reported fully in the literature include long term efficacy; potential to favourably influence cardiovascular and renovascular systems (and ultimately mortality) in patients with hypertension and, lastly, cost effectiveness and influence on quality of life. In summary, losartan potassium is the first AT(1)+ receptor antagonist to become available for the management of hypertension and, as such, it is an important new antihypertensive agent. Pending long term data as outlined above, it is likely to find initial use in patients with mild to severe hypertension who are unresponsive to, or intolerant of their current therapy. However, with its novel mechanism of action, good efficacy and favourable tolerability profile, losartan potassium is well placed to claim a prominent position in the management of patients with essential hypertension in the future.

Antihypertensive Agents↗

PubMed1996

Muromonab CD3: a reappraisal of its pharmacology and use as prophylaxis of solid organ transplant rejection.

The murine monoclonal antibody muromonab CD3 (OKT3) is directed against the CD3 antigen on peripheral human T cells and effectively blocks all T cell function. Prophylaxis with muromonab CD3 (5mg intravenously once daily for 10 to 14 days) as induction therapy together with corticosteroids, azathioprine and delayed cyclosporin (sequential therapy) optimises early graft function by delaying the potentially nephrotoxic and hepatotoxic effects of cyclosporin until graft function is established. Although clinical data are limited (by inconsistencies in trial design and trial size), prophylactic muromonab CD3-based sequential therapy is significantly more effective than standard triple therapy in the prophylaxis of allograft rejection in renal and hepatic, but not cardiac, transplant recipients. Benefits are particularly notable in patients with delayed graft function. No significant between-treatment differences in patient survival have been observed. The overall efficacy of muromonab CD3- and polyclonal-based prophylactic regimens appears to be similar, although results vary between investigators and confirmation is needed. An anti-interleukin-2 monoclonal antibody-based prophylactic regimen improved graft and patient survival compared with muromonab CD3-based prophylaxis in hepatic transplant recipients. Antimuromonab CD3 antibodies may develop; however, muromonab CD3 may be successfully reused in patients with low titres. Preliminary pharmacoeconomic data suggest that mean drug costs are greater with quadruple immunosuppressive regimens containing muromonab CD3, antithymocyte globulin (ATG) or antilymphocyte globulin (ALG) than with triple therapy. Drug costs with prophylactic muromonab CD3-based regimens were similar or greater than those with polyclonal-based protocols. The first doses of muromonab CD3 are associated with the 'cytokine-release syndrome'. More severe first-dose events include aseptic meningitis, intragraft thromboses, seizures and potentially fatal pulmonary oedema. The incidence and/or severity of cytomegalovirus infection with prophylactic muromonab CD3 based immunosuppression is similar to or greater than that with triple therapy and ATG- or ALG-based regimens. However, the risk of infection and also the observed increase in lymphoproliferative disorders appears to be related to the degree of immunosuppression rather than to the drug itself Thus, sequential muromonab CD3-based therapy is more effective than standard triple therapy (in renal and hepatic transplant recipients) and appears to be similar to that of polyclonal-based regimens in the prophylaxis of transplant rejection. Although the routine use of prophylactic muromonab CD3 in low-risk patients with primary graft function does not appear to be justified, prophylactic muromonab CD3-based therapy has a role in patients at high risk of rejection.

Animals↗

PubMed1996

Lisinopril. A review of its pharmacology and clinical efficacy in the early management of acute myocardial infarction.

Following establishment of its efficacy in hypertension and congestive heart failure, the ACE inhibitor lisinopril has now been shown to reduce mortality and cardiovascular morbidity in patients with myocardial infarction when administered as early treatment. The ability of lisinopril to attenuate the detrimental effects of left ventricular remodelling is a key mechanism; however, additional cardioprotective and vasculoprotective actions are postulated to play a role in mediating the early benefit. The GISSI-3 trial in > 19 000 patients has demonstrated that, when given orally within 24 hours of symptom onset and continued for 6 weeks, lisinopril (with or without nitrates) produces measurable survival benefits within 1 to 2 days of starting treatment. Compared with no lisinopril treatment, reductions of 11% in risk of mortality and 7.7% in a combined end-point (death plus severe left ventricular dysfunction) were evident at 6 weeks. Advantages were apparent in all types of patients. Thus, those at high risk-women, the elderly, patients with diabetes mellitus and those with anterior infarct and/or Killip class > 1 -also benefited. These gains in combined end-point events persisted in the longer term, despite treatment withdrawal after 6 weeks in most patients. At 6 months, the incidence rate for the combined end-point remained lower than with control (a 6.2% reduction). The GISSI-3 results concur with those from recent large investigations (ISIS-4, CCS-1, SMILE) of other ACE inhibitors as early management in myocardial infarction. However, the results of the CONSENSUS II trial (using intravenous enalaprilat then oral enalapril) were unfavourable in some patients. These findings, together with the development of persistent hypotension and, to a lesser extent, renal dysfunction among patients in the GISSI-3 trial, have prompted considerable debate over optimum treatment strategies. Present opinion generally holds that therapy with lisinopril or other ACE inhibitors shown to be beneficial may be started within 24 hours in haemodynamically stable patients with no other contraindications; current labelling in the US and other countries reflects this position. There is virtually unanimous agreement that such therapy is indicated in high-risk patients, particularly those with left ventricular dysfunction. The choice of ACE inhibitor appears less important than the decision to treat; it seems likely that these benefits are a class effect. Lisinopril has a tolerability profile resembling that of other ACE inhibitors, can be given once daily and may be less costly than other members of its class. However, present cost analyses are flawed and this latter points remains to be proven in formal cost-effectiveness analyses. In conclusion, early treatment with lisinopril (within 24 hours of symptom onset) for 6 weeks improves survival and reduces cardiovascular morbidity in patients with myocardial infarction, and confers ongoing benefit after drug withdrawal. While patients with symptoms of left ventricular dysfunction are prime candidates for treatment, all those who are haemodynamically stable with no other contraindications are also eligible to receive therapy. Lisinopril and other ACE inhibitors shown to be beneficial should therefore be considered an integral part of the early management of myocardial infarction in suitable patients.

Absorption↗

PubMed1996

Bezafibrate. An update of its pharmacology and use in the management of dyslipidaemia.

The lipid-modifying profile of bezafibrate is characterised by marked decreases in elevated triglyceride levels, increases in high density lipoprotein (HDL) cholesterol levels and decreases in total and low density lipoprotein (LDL) cholesterol levels. Bezafibrate also reduces elevated levels of lipoprotein(a) [Lp(a)] and fibrinogen, which are independent cardiovascular risk factors. Bezafibrate is effective in most types of primary and secondary dyslipidaemia. It is of greatest benefit in conditions featuring hypertriglyceridaemia and/or HDL cholesterol deficiency. This is particularly true for patients with diabetes mellitus, notably those with non-insulin-dependent diabetes mellitus (NIDDM) who are also likely to have increased fibrinogen levels. In the limited comparisons available, there appear to be few consistent differences in lipid-modifying effects between bezafibrate and other fibrates. Compared with HMG-CoA reductase inhibitors, bezafibrate causes larger changes in triglyceride and, in general, HDL cholesterol levels, and has a lesser influence on LDL and total cholesterol levels. These differences are advantageous when bezafibrate and HMG-CoA reductase inhibitors are used as combined therapy in patients with severe dyslipidaemia unresponsive to either modality alone. The combination of bezafibrate plus an HMG-CoA reductase inhibitor in clinical trials has not led to the predicted increase in myalgia. Indeed, bezafibrate is generally free of serious unwanted effects: rhabdomyolysis is rare and has occurred mainly in patients with renal dysfunction given excessive dosages. Other patient groups in whom bezafibrate has improved serum lipid profiles are those with isolated HDL cholesterol deficiency, dyslipidaemia secondary to renal insufficiency, and following cardiac surgery or other procedures. However, data for these indications are not extensive. Evidence is now available to show a beneficial effect of bezafibrate on retarding atherosclerotic processes and in reducing risk of coronary heart disease. The 5-year Bezafibrate Coronary Atherosclerosis Intervention Trial (BECAIT) in young male survivors of myocardial infarction demonstrated a smaller decrease in luminal diameter and a reduction in coronary events with bezafibrate compared with placebo. The Bezafibrate Infarction Prevention (BIP) study is expected to provide mortality data which is currently lacking for bezafibrate. In conclusion, bezafibrate is a useful and well-tolerated lipid-modifying agent in the management of primary and secondary dyslipidaemia. It has particularly beneficial effects in patients with hypertriglyceridaemia and/or low HDL cholesterol levels, and reduces fibrinogen levels. Together with its ability to sustain or improve glycaemic control, these properties make it a logical choice for treating patients with diabetes mellitus and dyslipidaemia. Additionally, the drug may be of value as combination therapy in patients with severe dyslipidaemia. Importantly, there is evidence that the drug can slow the atherosclerotic process and reduce cardiovascular morbidity. The ongoing BIP secondary intervention study and other investigations will help clarify the effects of bezafibrate on cardiovascular mortality and morbidity.

Angina Pectoris↗

PubMed1996

Iodixanol. A review of its pharmacodynamic and pharmacokinetic properties and diagnostic use as an x-ray contrast medium.

Iodixanol is an iso-osmolal nonionic dimeric hydrophilic contrast agent. It has similar diagnostic efficacy to that of other iodinated contrast media. Because of its physical properties, iodixanol would be expected to produce a lower incidence of adverse events than other nondimeric contrast media. Indeed, pharmacodynamic studies indicate that iodixanol has fewer cardiovascular effects, causes less renal damage and is associated with similar or smaller changes to the blood-brain barrier and neurological function when compared with nondimeric nonionic contrast media. In clinical trials, iodixanol had a similar tolerability profile to other nonionic contrast media but induced fewer adverse events than ioxaglate. Iodixanol appears to have an advantage over other contrast media in that it generally causes less frequent and less intense discomfort on injection. However, in common with other newer, and usually nonionic, contrast media, iodixanol is expensive. Studies investigating other nonionic contrast media (but not iodixanol) have shown that it is not cost-effective in all patients to replace older, usually ionic, contrast media with the more costly newer alternatives. Nonetheless, in selected patients who are considered at increased risk of contrast medium-associated adverse events, nonionic agents should be used. Iodixanol, with its lower intensity (and possibly frequency) of discomfort, may be a preferred option in these patients.

Animals↗