Biomedical subjects

Steven Gabardi

Publications and source records attributed to Steven Gabardi.

10 recordsLinked to original sources

PubMed2005

Drug dosing in chronic kidney disease.

Patients with chronic kidney disease (CKD) are at high risk for adverse drug reactions and drug-drug interactions. Drug dosing in these patients often proves to be a difficult task. Renal dysfunction-induced changes in human pathophysiology regularly results may alter medication pharmacodynamics and handling. Several pharmacokinetic parameters are adversely affected by CKD, secondary to a reduced oral absorption and glomerular filtration; altered tubular secretion; and reabsorption and changes in intestinal, hepatic, and renal metabolism. In general, drug dosing can be accomplished by multiple methods; however, the most common recommendations are often to reduce the dose or expand the dosing interval, or use both methods simultaneously. Some medications need to be avoided all together in CKD either because of lack of efficacy or increased risk of toxicity. Nevertheless, specific recommendations are available for dosing of certain medications and are an important resource, because most are based on clinical or pharmacokinetic trials.

Biotransformation↗

PubMed2004

Pharmacoepidemiology of anemia in kidney transplant recipients.

ABSTRACT. Anemia has long been known to be a complication of end-stage renal disease (ESRD), and it has been linked to cardiovascular morbidity and mortality. Although kidney transplant recipients (KTR) are prone to experiencing cardiovascular outcomes, little is known about the epidemiology of anemia in this population. With few exceptions, studies to date have not fully evaluated the associations between posttransplant anemia (PTA) and medications commonly used in KTR, particularly immunosuppressant drugs, angiotensin-converting enzyme inhibitors (ACEI) and angiotensin II receptor blockers (ARB). The authors aimed to specifically investigate possible associations between these drugs and PTA. Detailed medical information was retrospectively collected on 374 consecutive KTR from our transplant clinic. Univariate/multivariate linear regression models were used to test for associations between hematocrit (HCT) and other covariates, and logistic regression models were used to detect independent predictors of PTA, defined as HCT <33%. The mean time since transplantation was 7.7 yr, and mean creatinine was 2.2 mg/dl. The prevalence of PTA was 28.6%. Ten percent of all patients were on erythropoietin therapy, but only 41.6% of patients whose HCT was <30 received this treatment. From multivariate analyses, the authors found that female gender and lower renal function were associated with lower HCT (both P < 0.001). Patients on ACEI had significantly lower HCT (P = 0.005) compared with patients without such treatment. In addition, a significant curvilinear dose-response relationship was found between ACEI dose and HCT. Among the immunosuppressant drugs, mycophenolate mofetil (P = 0.05) and tacrolimus (P = 0.02) were associated with a lower HCT. The authors conclude that PTA is prevalent and undertreated in KTR. Several medications that are possibly modifiable correlates of PTR deserve further study.

Adult↗

PubMed2004

Treating gout in kidney transplant recipients.

OBJECTIVE: To review the etiology, treatment, and preventive strategies of hyperuricemia and gout in kidney transplant recipients. DATA SOURCES: Primary literature was obtained via Medline (1966-June 2003). STUDY SELECTION AND DATA EXTRACTION: Studies evaluating treatment and prevention of hyperuricemia and gout in kidney transplantation were considered for evaluation. English-language studies were selected for inclusion. DATA SYNTHESIS: Approximately 14,000 kidney transplantations were performed in the United States in 2003, and of those transplant recipients, nearly 13% will experience a new onset of gout. The prevalence of hyperuricemia is even greater. There are several mechanisms by which hyperuricemia and gout develop in kidney transplant recipients. Medication-induced hyperuricemia and renal dysfunction are 2 of the more common mechanisms. Prophylactic and treatment options include allopurinol, colchicine, corticosteroids, and, if absolutely necessary, nonsteroidal antiinflammatory drugs. CONCLUSION: It is generally recommended to decide whether the risks of prophylactic therapy and treatment outweigh the benefits. Often, the risk of adverse events associated with agents to treat these ailments tends to outweigh the benefits; therefore, treatment is usually reserved for symptomatic episodes of acute gout. Practitioners must also decide if changes in immunosuppressive regimens may be of benefit on a patient-by-patient basis.

Acute Disease↗

PubMed2004

Future immunosuppressive agents in solid-organ transplantation.

OBJECTIVE: To review the pharmacology, pharmacokinetics, efficacy, and safety of mycophenolate sodium, everolimus, and FTY720. STUDY SELECTION AND DATA EXTRACTION: Clinical trials and abstracts evaluating mycophenolate sodium, everolimus, and FTY720 in solid-organ transplantation were considered for evaluation. English-language studies and published abstracts were selected for inclusion. DATA SYNTHESIS: Mycophenolate sodium has recently been approved by the Food and Drug Adminstration for marketing in the United States; everolimus and FTY720 are immunosuppressive agents that may soon be available in the United States. These agents have proven efficacy in reducing the incidence of acute rejection in solid-organ transplantation. Clinical trials have shown that these newer agents are relatively well tolerated. The most common adverse events associated with these agents were gastrointestinal and hematologic effects (mycophenolate sodium); hyperlipidemia, increased serum creatinine, and hematologic effects (everolimus): and gastrointestinal effects, headache, and bradycardia (FTY720). CONCLUSION: Mycophenolate sodium has been approved in some European countries and the United States. Everolimus has been approved in some European countries and a new drug application has been submitted to the Food and Drug Administration. FTY720 is currently in phase III clinical trials and submission to the Food and Drug Administration for approval is a few years away. The approval of these agents will furnish the transplant practitioner with even more options for immunosuppression.

Drug Approval↗

PubMed2004

Nonprescription analgesics and their use in solid-organ transplantation: a review.

OBJECTIVE: To review the pharmacology, adverse events, drug interactions, and use of the nonprescription analgesics in solid-organ transplant recipients. STUDY SELECTION AND DATA EXTRACTION: Studies evaluating nonprescription analgesics in solid-organ transplantation were considered for evaluation. English-language studies were selected for inclusion. DATA SYNTHESIS: Nonprescription analgesics (aspirin, choline salicylate, magnesium salicylate, sodium salicylate, ibuprofen, ketoprofen, naproxen sodium, and acetaminophen) are the most commonly purchased over-the-counter agents in the United States. These agents, although generally considered safe, have been associated with a number of toxicities. The salicylates and nonsteroidal anti-inflammatory drugs have been associated with gastrointestinal damage, hematologic changes, liver and kidney dysfunction, and breathing difficulties. Acetaminophen has been shown to induce hematologic changes and liver and renal dysfunction. CONCLUSION: A closer look at the nonprescription analgesics reveals their potential for harm when used by solid-organ transplant recipients. In this patient population, the salicylates and nonsteroidal anti-inflammatory drugs should generally be avoided if possible, because of their potential toxicities, especially renal dysfunction. Low-dose aspirin, for the prevention of cardiovascular and cardiocerebral events, appears to be safe, but patients must still be followed closely. Acetaminophen is generally considered the nonprescription analgesic and antipyretic of choice in transplant recipients because of its favorable toxicity profile. However, it is imperative that patients and transplant practitioners are aware that this agent is not without toxicities and proper monitoring is advised.

Analgesics↗

PubMed2004

Efficacy and safety of low-dose valganciclovir for prevention of cytomegalovirus disease in renal transplant recipients: a single-center, retrospective analysis.

STUDY OBJECTIVE: To evaluate the safety and efficacy of valganciclovir 450 mg/day for 6 months for cytomegalovirus (CMV) prophylaxis in renal transplant recipients. DESIGN: Single-center, retrospective analysis. SETTING: Urban, academic medical center. PATIENTS: Fifty-eight patients who received de novo renal transplants from August 1, 2001-November 21, 2002. INTERVENTION: Valganciclovir 450 mg/day was administered to all renal transplant recipients at risk for CMV disease. Therapy was begun postoperatively and was dose adjusted to renal function. MEASUREMENTS AND MAIN RESULTS: Data collected from renal transplant recipients were demographics, immunosuppressive and antiviral drug therapy, and occurrence of CMV disease, acute rejection, allograft loss, and hematologic adverse events. Donor (D)/recipient (R) CMV serostatus was 37.9% D+/R+, 29.3% D-/R+, 17.3% D+/R-, and 15.5% D-/R-. Antithymocyte globulin (ATG) was administered to 62.1% of patients. Most of the transplant recipients received triple immunosuppression as maintenance therapy. Median follow-up was 20 months. The frequency of CMV disease was 1.7% within 6 months after transplantation and 5.2% at any point after transplantation. All patients who developed CMV disease were D+/R- and had received ATG. Leukopenia and thrombocytopenia associated with valganciclovir were seen in 28% and 24% of patients, respectively. One patient developed acute cellular rejection. No graft losses or deaths occurred. Early discontinuation of valganciclovir occurred in 20% of patients secondary to severe, persistent leukopenia, thrombocytopenia, and/or diarrhea. None of these patients developed CMV disease. CONCLUSION: A high rate of CMV disease was noted among the D+/R- population. Administration of ATG as an induction agent also increased the frequency of CMV disease. Despite the low dosage of valganciclovir, hematologic adverse events were common. However, valganciclovir, administered at 450 mg/day for 6 months, was effective and relatively safe for prophylaxis of CMV disease in renal transplant recipients.

Adult↗

PubMed2003

Bitter melon (Momordica charantia): a review of efficacy and safety.

The pharmacology, clinical efficacy, adverse effects, drug interactions, and place in therapy of bitter melon are described. Bitter melon (Momordica charantia) is an alternative therapy that has primarily been used for lowering blood glucose levels in patients with diabetes mellitus. Components of bitter melon extract appear to have structural similarities to animal insulin. Antiviral and antineoplastic activities have also been reported in vitro. Four clinical trials found bitter melon juice, fruit, and dried powder to have a moderate hypoglycemic effect. These studies were small and were not randomized or double-blind, however. Reported adverse effects of bitter melon include hypoglycemic coma and convulsions in children, reduced fertility in mice, a favism-like syndrome, increases in gamma-glutamyltransferase and alkaline phosphatase levels in animals, and headaches. Bitter melon may have additive effects when taken with other glucose-lowering agents. Adequately powered, randomized, placebo-controlled trials are needed to properly assess safety and efficacy before bitter melon can be routinely recommended. Bitter melon may have hypoglycemic effects, but data are not sufficient to recommend its use in the absence of careful supervision and monitoring.

Animals↗

PubMed2003

Enteric-coated mycophenolate sodium.

OBJECTIVE: To review the pharmacology, pharmacokinetics, efficacy, and safety of mycophenolate sodium. DATA SOURCES: Primary literature was obtained via a MEDLINE search (1966-June 2003). Abstracts were obtained from the manufacturer and included in the analysis. STUDY SELECTION AND DATA EXTRACTION: All studies and abstracts evaluating mycophenolate sodium in solid organ transplantation were considered for inclusion. English-language studies and abstracts were selected for inclusion, but were limited to those consisting of human subjects. DATA SYNTHESIS: Mycophenolate sodium, a mycophenolic acid prodrug, is an inhibitor of T-lymphocyte proliferation. Mycophenolic acid reduces the incidence of acute rejection in renal transplantation. Mycophenolate sodium is enteric coated and has been suggested as a potential method to reduce the gastrointestinal adverse events seen with mycophenolate mofetil. Both mycophenolate mofetil and mycophenolate sodium have been shown to be therapeutically equivalent at decreasing the incidence of allograft rejection and loss. The frequency of adverse events is similar between both compounds, with the most common events being diarrhea and leukopenia. CONCLUSIONS: Mycophenolate sodium is effective in preventing acute rejection in renal transplant recipients. At doses of 720 mg twice daily, the efficacy and safety profiles are similar to those of mycophenolate mofetil 1000 mg twice daily. Mycophenolate sodium has been approved in Switzerland; approval in the US is pending.

Adolescent↗

PubMed2003

Calcium channel blockers as the treatment of choice for hypertension in renal transplant recipients: fact or fiction.

Posttransplantation hypertension has been identified as an independent risk factor for chronic allograft dysfunction and loss. Based on available morbidity and mortality data, posttransplantation hypertension must be identified and managed appropriately. During the past decade, calcium channel blockers have been recommended by some as the antihypertensive agents of choice in this population, because it was theorized that their vasodilatory effects would counteract the vasoconstrictive effects of the calcineurin inhibitors. With increasing data becoming available, reexamining the use of traditional antihypertensive agents, including diuretics and beta-blockers, or the newer agents, angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers, may be beneficial. Transplant clinicians must choose antihypertensive agents that will provide their patients with maximum benefit, from both a renal and a cardiovascular perspective. Beta-blockers, diuretics, and ACE inhibitors have all demonstrated significant benefit on morbidity and mortality in patients with cardiovascular disease. Calcium channel blockers have been shown to possess the ability to counteract cyclosporine-induced nephrotoxicity. When compared with beta-blockers, diuretics, and ACE inhibitors, however, the relative risk of cardiovascular events is increased with calcium channel blockers. With the long-term benefits of calcium channel blockers on the kidney unknown and a negative cardiovascular profile, these agents are best reserved as adjunctive therapy to beta-blockers, diuretics, and ACE inhibitors.

Adrenergic beta-Antagonists↗

PubMed2002

Intravenous to oral conversion of fluoroquinolones: knowledge versus clinical practice patterns.

STUDY OBJECTIVES: To assess the knowledge of prescribers regarding intravenous to oral conversions of fluoroquinolones, the frequency and time until conversion, and to compare prescriber knowledge with the data collected concerning the reasons stated for continuation of intravenous fluoroquinolones. DESIGN: Prospective chart review and questionnaire. SETTING: Large teaching hospital in Paris, France. PATIENTS: Fifty-one males and females. INTERVENTION: Data were collected on in-patients receiving intravenous fluoroquinolone for at least three days and hospitalized in one of six in-patient units. Patients receiving intravenous fluoroquinolone for less than three days were excluded. A questionnaire to assess the awareness of a potential conversion was distributed to those practitioners who had patients reviewed during the data-collection phase. MAIN RESULTS: The questionnaire revealed the ten most common reasons for continuing intravenous administration for more than three days. However, the physicians agreed that most patients should be converted as soon as possible. Practice patterns differed, with only 17 of 51 patients actually converted to oral therapy. CONCLUSION: In theory, the clinicians were aware of when to perform the conversion. However, in practice, the frequency of conversion was lower than optimum. Changes in clinical practice are needed to decrease the costs of intravenous therapy, without jeopardizing quality of care.

Administration, Oral↗