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Biomedical subjects

R H Drew

Publications and source records attributed to R H Drew.

26 records · Page 2Linked to original sources

The use of hydroxocobalamin in the prophylaxis and treatment of nitroprusside-induced cyanide toxicity.

The use of OHB12 in the prophylaxis of CN intoxication resulting from SNP infusions is well documented in the literature. However, data is lacking to support its use as an antidote once signs and symptoms have developed. Because of the efficacy of oxygen therapy combined with supportive therapy and nitrite/sodium thiosulfate administration, the use of OHB12 as an antidote cannot be recommended at this time. Further studies are needed to determine efficacy, dosing, mode of administration and comparative trials to other antidotes.

Animals↗

Amphotericin B: 30 years of clinical experience.

Amphotericin B, the first commercially significant antifungal drug, has been available for more than 30 years. This polyene macrolide antifungal agent continues to play a major role in the treatment of systemic fungal infections, despite the introduction of newer agents such as the azoles. Given the proved efficacy of amphotericin B--and the increasing number of indications for antifungal agents--an extensive review of this drug is warranted. This paper discusses the clinical uses of amphotericin B, including its application in AIDS-related fungal infections, in neutropenic cancer patients who are persistently febrile, and in infections of the central nervous system, lung, peritoneum, genitourinary system, eye, and skin. The paper also reviews the drug's adverse reactions, with a discussion of administration techniques that may reduce these reactions, and its spectrum of activity, pharmacokinetics, and dosage and administration.

Amphotericin B↗

Adverse drug reactions to systemic antifungals. Prevention and management.

Systemic administration of antifungal agents for invasive mycoses has dramatically increased over the past 10 years in many fields of medicine. The increase has been due both to an increasing immune compromised population and to potent antibacterial agents which allow these fungi to invade tissue. It is apparent that our understanding of the use of both the old and new antifungal agents has significantly increased in the last few years. In this review, we attempt to document our extensive knowledge of the adverse effects of the polyenes, flucytosine, griseofulvin and azoles when given systemically for treatment. Interwoven in this documentation of the adverse reactions to these agents is the attempt to help clinicians potentially avoid some of these adverse effects and if they do occur, to be able to identify and successfully manage them.

Antifungal Agents↗

Effect of simultaneous didanosine administration on itraconazole absorption in healthy volunteers.

STUDY OBJECTIVE: To investigate the effect of simultaneously administered didanosine (ddI) on the absorption of a single dose of itraconazole. DESIGN: Randomized, crossover, unblinded single-dose pharmacokinetic study in healthy volunteers. Comparisons of itraconazole alone and itraconazole with simultaneous ddI were performed on days 1 and 15. SETTING: A university medical center. PATIENTS: Seven healthy men and women. Six subjects (86%) completed the study; one was removed due to the development of a rash. INTERVENTIONS: Volunteers received a single 200-mg oral dose of itraconazole or itraconazole with concomitant oral ddI 300 mg (two 150-mg tablets) dispersed in 240 ml water. Each regimen was separated by a 2-week washout period. Serum samples were obtained frequently for 12 hours after the dose. MEASUREMENTS AND MAIN RESULTS: Concentrations of itraconazole were determined using a microbiologic assay. Individual concentrations in serum versus time data were evaluated by linear regression analysis. Peak serum concentration and time to peak were determined by visual inspection of each individual's serum concentration-time curve. A mean +/- SD peak serum itraconazole concentration of 0.90 +/- 0.30 micrograms/ml was observed at 3.0 +/- 0.7 hours when itraconazole was administered alone, compared with undetectable levels in all patients during therapy with ddI. CONCLUSIONS: Simultaneous oral administration of ddI significantly decreases absorption of itraconazole. These drugs should not be administered concurrently.

Administration, Oral↗

Treatment of vancomycin-resistant enterococci, with a focus on quinupristin-dalfopristin.

Enterococci are the second most common cause of hospital-acquired infections, and drug resistance among these organisms is a growing problem. Vancomycin-resistant enterococci (VRE) now account for 7.9% of the nosocomial enterococcal infections. There is no standard therapy for VRE. Although some agents have shown in vitro activity alone or in combination, including ciprofloxacin, doxycycline, novobiocin, teicoplanin, chloramphenicol, and rifampin, treatment options are limited to combinations of drugs with marginal efficacy against the pathogens. Quinupristin-dalfopristin is a new investigational agent with activity against gram-positive cocci, including VRE.

Anti-Bacterial Agents↗

A prospective, open-label study of single-dose ciprofloxacin absorption after chemotherapy in patients with malignancy.

The absorption of a single oral dose of ciprofloxacin 750 mg in patients with cancer who had chemotherapy-induced Cancer and Leukemia Group B grade I or II mucositis was evaluated. Ciprofloxacin was administered after an overnight fast. Plasma samples were collected before and 0.5, 1, 1.5, 2, 3, 4, 6, 8, and 12 hours after the dose. Drug concentrations were determined by reverse-phase high-performance liquid chromatography with fluorescence detection. Pharmacokinetic values were characterized by noncompartmental methods. The mean +/- SD for area under the curve, mean peak concentration (C(max)), and time to C(max) (T(max)) were 18.7 +/- 5.03 mg/L x hour, 4.41 +/- 1.74 mg/L, and 1.81 +/- 0.843 hours, respectively. The absorption of oral ciprofloxacin in patients with chemotherapy-induced grade I or II mucositis compares with that in healthy volunteers. These findings may call for further pharmacokinetic evaluation of the drug in a similar patient population.

Adult↗

Chest discomfort associated with liposomal amphotericin B: report of three cases and review of the literature.

Liposomal formulations of amphotericin B are designed to maintain therapeutic efficacy of amphotericin B deoxycholate while reducing its associated toxicities. In three patients chest discomfort occurred during planned 1-hour infusions of liposomal amphotericin B (AmBisome) 3 mg/kg/day during an open-label trial. The first patient experienced chest tightness and difficulty breathing and the second had dyspnea and acute hypoxia, both within 10 minutes of the start of the infusion. The third patient complained of chest pain 5 minutes after the start of two infusions. All symptoms resolved on terminating therapy. Two patients were later rechallenged with slower infusions and tolerated the drug well. A review of the English-language literature revealed only two other case reports of infusion-related chest or pulmonary reactions with the drug, although similar reactions were noted in several reports of clinical trials. Further review of the literature revealed reports of chest and pulmonary adverse events with other liposomal formulations of amphotericin B, liposomal daunorubicin, liposomal doxorubicin, and liposomes. The pathophysiology of such reactions remains unclear, and premedication with diphenhydramine did not completely prevent this reaction in one of our patients. We recommend infusing liposomal amphotericin B over at least 2 hours with careful monitoring for adverse reactions.

Adolescent↗