Biomedical subjects

H D Langtry

Publications and source records attributed to H D Langtry.

28 records · Page 2Linked to original sources

PubMed1991

Bopindolol. A review of its pharmacodynamic and pharmacokinetic properties and therapeutic efficacy.

Bopindolol is a nonselective beta-adrenoceptor antagonist [corrected] with partial agonist activity which is used in the treatment of hypertension. The drug is rapidly metabolised to an active hydrolysed form. The antihypertensive effects of bopindolol 0.5 to 4 mg are sustained for more than 24 hours after once daily dosing, and the drug appears similar in efficacy to propranolol, metoprolol, atenolol, pindolol and slow release nifedipine in the treatment of mild to moderate forms of this disease. In limited trials bopindolol has also successfully reduced symptoms in patients with angina pectoris, anxiety and essential tremor. Thus, bopindolol is an effective and well-tolerated beta-adrenoceptor antagonist.

Adrenergic beta-Antagonists↗

PubMed1991

Mitoxantrone. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in the chemotherapy of cancer.

Mitoxantrone is a dihydroxyanthracenedione derivative which as intravenous mono- and combination therapy has demonstrated therapeutic efficacy similar to that of standard induction and salvage treatment regimens in advanced breast cancer, non-Hodgkin's lymphoma, acute nonlymphoblastic leukaemia and chronic myelogenous leukaemia in blast crisis; it appears to be an effective alternative to the anthracycline component of standard treatment regimens in these indications. Mitoxantrone is also effective as a component of predominantly palliative treatment regimens for hepatic and advanced ovarian carcinoma. Limited studies suggest useful therapeutic activity in multiple myeloma and acute lymphoblastic leukaemia. Regional therapy of malignant effusions, hepatic and ovarian carcinomas has also been very effective, with a reduction in systemic adverse effects. Mitoxantrone inhibits DNA synthesis by intercalating DNA, inducing DNA strand breaks, and causing DNA aggregation and compaction, and delays cell cycle progression, particularly in late S phase. In vitro antitumour activity is concentration- and exposure time-proportional, and synergy with other antineoplastic drugs has been demonstrated in murine tumour models. Leucopenia may be dose-limiting in patients with solid tumours, whereas stomatitis may be dose-limiting in patients with leukaemia. Other adverse effects are usually of mild or moderate severity although cardiac effects, particularly congestive heart failure, may be of concern, especially in patients with a history of anthracycline therapy, mediastinal irradiation or cardiovascular disease. Mitoxantrone displays an improved tolerability profile compared with doxorubicin and other anthracyclines, although myelosuppression may occur more frequently. Thus, mitoxantrone is an effective and better tolerated alternative to the anthracyclines in most haematological malignancies, in breast cancer and in advanced hepatic or ovarian carcinoma. Further studies may consolidate its role in the treatment of these and other malignancies.

Animals↗

PubMed1990

Pergolide. A review of its pharmacological properties and therapeutic potential in Parkinson's disease.

When used to treat patients with Parkinson's disease pergolide acts at dopamine receptors in the corpus striatum to improve locomotor activity, reducing the tremor, gait disturbances, bradykinesia or akinesia and rigidity experienced by such patients. Treatment with pergolide often allows substantial reductions in concomitant levodopa dosage, and occasionally levodopa can be completely replaced by pergolide therapy in short term use. Pergolide has a long duration of action, thus reducing the wearing-off and end-of-dose phenomena frequently seen with long term levodopa therapy, suppressing fluctuations in levodopa response, and increasing total 'on' time. Despite a lack of well controlled studies comparing this drug with other dopamine agonist agents, pergolide appears to result in adverse effects and anti-Parkinson responses similar to those of bromocriptine and lisuride. Thus, pergolide would appear to be at least as useful as other dopamine agonists such as bromocriptine or lisuride for the management of patients with Parkinson's disease when administered in combination with levodopa. Future research should be directed towards establishing which patients are most likely to benefit from pergolide therapy, and clarifying the relative efficacy and safety of the anti-Parkinsonian drugs available to the clinician. If pergolide does provide clinical benefit when substituted for levodopa-adjunct drugs that are producing less than optimal control, this will be an advantage in a disease area which at present has few therapeutic options.

Animals↗

PubMed1990

Zolpidem. A review of its pharmacodynamic and pharmacokinetic properties and therapeutic potential.

Zolpidem is an imidazopyridine, a chemically novel nonbenzodiazepine hypnotic agent which acts at the benzodiazepine omega 1-receptor subtype in the brain. With a rapid onset of action and short elimination half-life, it reduces the latency to and prolongs the duration of sleep in patients with insomnia, yet has no major effects on sleep stages when given in dosages of 5 to 20 mg nightly. Rebound effects on withdrawal of the drug have not been observed. Unlike benzodiazepines, zolpidem has no myorelaxant or anticonvulsant effects and its effects on anxiety appear to be minor. While zolpidem aids sedation, and may reduce memory or psychomotor function within the first 2 hours after administration of single oral doses, its use as a surgical premedicant remains to be established. Adverse effects are predominantly CNS and gastrointestinal in nature. Altered pharmacokinetics may lead to an increase in dose-proportionate adverse effects in the elderly and in patients with renal dysfunction. Limited evidence to date suggests that the dependence liability of zolpidem is minimal. Thus, zolpidem is an interesting alternative to benzodiazepines in the treatment of insomnia, with properties that potentially offer worthwhile advantages in this therapeutic area if they are confirmed with wider clinical experience.

Drug Interactions↗

PubMed1990

Terodiline. A review of its pharmacological properties, and therapeutic use in the treatment of urinary incontinence.

Terodiline has both anticholinergic and calcium antagonist properties and, as a result, effectively reduces abnormal bladder contractions caused by detrusor instability. When administered to adult patients with urge incontinence (generally as a 25mg twice-daily dose) terodiline reduces diurnal and nocturnal micturition frequency and incontinence episodes. In studies also assessing cystometric parameters, bladder volume at first urge and bladder capacity are increased. Children with diurnal enuresis respond similarly to a daily 25mg dose. Several studies have shown that terodiline 50 mg/day is preferred by patients when compared with emepronium 600 mg/day or flavoxate 600 mg/day, and tends to reduce voluntary micturition frequency and episodes of incontinence more effectively than these drugs. Terodiline is well tolerated in short and long term (up to 3.5 years) studies. Anticholinergic effects are most commonly reported; other adverse effects occur equally during terodiline and placebo treatment. Thus, terodiline is effective and well tolerated in patients with urge incontinence or neurogenic bladder dysfunction, and will claim an important place in the treatment of such patients in light of the limitations of alternative therapies.

Animals↗

PubMed1990

Transdermal nitroglycerin (glyceryl trinitrate). A review of its pharmacology and therapeutic use.

Nitroglycerin (glyceryl trinitrate) has been used for many years via the sublingual route for treating acute anginal attacks. In recent years transdermal delivery of nitroglycerin has gained popularity for prophylaxis against angina. However, nitrate tolerance appears to be a therapeutic problem with all long-acting nitrates regardless of delivery mechanism, and it occurs in most patients with stable angina treated with continuous 24-hour application of nitroglycerin patches. Since continuous 24-hour plasma concentrations of nitroglycerin do not appear to be desirable, alternative approaches to therapy are needed. A simple method to minimise tolerance with transdermal nitroglycerin patches is to remove the patch at bedtime and reapply a new patch in the morning. Such intermittent therapy allows a patch-free period during the night, when most patients experience few angina attacks, but optimises nitrate sensitivity during the daytime. However, the place of intermittent nitroglycerin patch therapy in the treatment of stable angina needs clarification with further study, particularly comparisons with other long-acting forms of nitrates. There are insufficient data to recommend the use of transdermal nitroglycerin patches in the treatment of patients with unstable angina or congestive heart failure. In conclusion, transdermal nitroglycerin patches offer a convenient and cosmetically acceptable dosage form which has potential use in stable angina if administered as an intermittent regimen providing a patch-free period each night.

Administration, Cutaneous↗

PubMed1989

Zidovudine. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy.

Zidovudine (azidothymidine) is a thymidine analogue antiretroviral drug active against human immunodeficiency virus (HIV). In acquired immunodeficiency syndrome (AIDS) and AIDS-related complex (ARC) patients, orally and intravenously administered zidovudine is effective in reducing the incidence of opportunistic infections and neoplasms, increasing helper T lymphocyte numbers, and improving survival rates and quality of life. Adverse effects include serious haematological abnormalities and severe headache, abdominal discomfort, nausea, myalgia and insomnia. In addition, neutropenia and other anaemias frequently limit zidovudine therapy and may result in a need for multiple blood transfusions, dose reductions or withdrawal of the drug. However, despite these problems and the lack of information about some aspects of zidovudine use, zidovudine provides a major hope for HIV-infected patients, and it has rapidly become the standard therapy for improving the quality and duration of the lives of AIDS and ARC patients.

Acquired Immunodeficiency Syndrome↗

PubMed1989

Ranitidine. An updated review of its pharmacodynamic and pharmacokinetic properties and therapeutic use in peptic ulcer disease and other allied diseases.

Ranitidine, a histamine H2-receptor antagonist, is now well established as a potent inhibitor of gastric acid secretion effective in the treatment and prophylaxis of gastrointestinal lesions aggravated by gastric acid secretion. Therapeutic trials involving several thousands of patients with peptic ulcer disease confirm that ranitidine 300mg daily administered orally in single or divided doses is at least as effective as cimetidine 800 to 1000mg daily in increasing the rate of healing of duodenal and gastric ulcers. Similar dosages of ranitidine have been shown to relieve the symptoms of reflux oesophagitis and heal or prevent gastrointestinal damage caused by ulcerogenic drugs. Ranitidine 150mg orally at night maintains ulcer healing in the long term. Ranitidine has also demonstrated good results in the treatment of Zollinger-Ellison syndrome and in the prevention of aspiration pneumonitis when given prior to surgery and to pregnant women at full term. It may also have a place in the management of acute upper gastrointestinal bleeding and in the prevention of stress ulcers in the intensive care setting, although these areas require further investigation. Ranitidine has been used safely in obstetric patients during labour, in children, the elderly, and in patients with renal impairment when given in appropriate dosages. The drug is very well tolerated and is only infrequently associated with serious adverse reactions or clinically significant drug interactions. Even at high dosages, ranitidine appears devoid of antiandrogenic effects. Ranitidine is clearly comparable or superior to most other antiulcer agents in the treatment and prevention of a variety of gastrointestinal disorders associated with gastric acid secretion. With its favourable efficacy and tolerability profiles, ranitidine must be considered a first-line agent when suppression of gastric acid secretion is indicated.

Animals↗

PubMed1989

Famotidine. An updated review of its pharmacodynamic and pharmacokinetic properties, and therapeutic use in peptic ulcer disease and other allied diseases.

Famotidine is a highly selective histamine H2-receptor antagonist. In healthy volunteers and patients with acid hypersecretory disease it is approximately 20 to 50 times more potent at inhibiting gastric acid secretion than cimetidine and 8 times more potent than ranitidine on a weight basis. As shown in placebo-controlled trials, famotidine is effective in healing both duodenal and gastric ulcers. Famotidine 20mg twice daily or 40mg at bedtime achieves healing rates and symptom relief similar or superior to those achieved by cimetidine 800mg daily or ranitidine 300mg daily in patients with peptic ulcer disease. Results of 1 placebo-controlled study suggest that famotidine prevents recurrence of duodenal ulcer, but comparative trials are needed to establish its relative efficacy in maintenance therapy. The few non-comparative trials conducted to date also suggest that famotidine 10 to 20mg twice daily may be effective in the treatment of gastritis and reflux gastro-oesophagitis. In comparative trials, famotidine was similar in efficacy to cimetidine in the treatment of upper gastrointestinal bleeding and to ranitidine in the prevention of pulmonary aspiration of acid. In patients with Zollinger-Ellison syndrome, the potency and long duration of action of famotidine may confer an advantage over other H2-receptor antagonists--in individualised doses (mean 0.33 g/day) famotidine successfully controlled acid secretion for up to 72 months in 1 study of such patients. Accumulated clinical evidence confirms that famotidine is very well tolerated and is free of the antiandrogenic effects infrequently reported with cimetidine. Moreover, famotidine is not associated with altered hepatic metabolism of drugs. Thus, famotidine is an effective, well-tolerated alternative to cimetidine and ranitidine. Famotidine is also promising as maintenance therapy for preventing recurrence of duodenal ulcer and as initial or maintenance treatment of gastric hypersecretory disorders, but further clinical experience, particularly in the long term, is needed to define the relative efficacy and tolerability of famotidine in these indications.

Famotidine↗

PubMed1989

Urapidil. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in the treatment of hypertension.

Urapidil is a postsynaptic alpha 1-adrenoceptor antagonist with a pharmacodynamic profile similar to prazosin. Unlike prazosin, however, urapidil also has some central activity which may explain the apparent improved tolerability of urapidil, including the absence of first-dose syncope. In clinical trials urapidil therapy resulted in significant reductions in blood pressure in patients with mild to severe essential hypertension, with little influence on heart rate. It is an effective antihypertensive when administered as monotherapy or in combination with beta-blockers and thiazide diuretics. In the few patients with cardiac dysfunction who have been studied to date, urapidil has improved myocardial oxygen consumption, systemic vascular resistance, left ventricular function, cardiac output and pulmonary capillary wedge pressure; however, further study is needed to assess the full therapeutic potential of urapidil in these patients. Urapidil has also been used successfully in the treatment of hypertensive emergencies, including eclampsia and pre-eclampsia, hypertensive crisis and hypertension occurring during general and cardiac surgery, rapidly lowering blood pressure without altering heart rate. Urapidil does not affect lipid or glucose metabolism, nor does it impair renal function. In addition, urapidil may be beneficial to patients with pulmonary hypertension, in whom it dilates pulmonary vascular beds to a greater extent than systemic vasculature, although therapeutic trials have not examined this effect. The most common adverse effects associated with urapidil therapy are dizziness, nausea, headache, fatigue and palpitations; however, these tend to be mild and transient and usually do not require discontinuation of treatment. Thus, urapidil offers a useful alternative to currently available drugs for the treatment of mild to severe hypertension, either as monotherapy or in combination with other antihypertensive drugs.

Animals↗