Zidovudine Dapsone

Drugs that may be affected by probenecid include acyclovir allopurinol barbiturates benzodiazepines clofibrate dapsone dyphylline methotrexate NSAIDs pantothenic acid penicillamine rifampin sulfonamides sulfonylureas zidovudine salicylates. 

Drugs that may affect zidovudine include acetaminophen, atovaquone, bone marrow suppressive/cytotoxic agents (eg, adriamycin, dapsone), clarithromycin, doxorubicin, fluconazole, ganciclovir, methadone, nelfinavir/ritonavir, phenytoin, probenecid, ribavirin, rifamycins, stavudine, trimethoprim, and valproic acid. 

Drugs that may be affected by TMP-SMZ include anticoagulants, cyclosporine, dapsone, diuretics, hydantoins, methotrexate, sulfonylureas, and zidovudine. Drugs that may affect TMP-SMZ include dapsone. 

Trimethoprim has been reported to decrease the therapeutic effect of cyclosporine with a concomitant increased risk of nephrotoxicity. Increased levels of dapsone, warfarin, methotrexate, zidovudine, and sul-fonylureas may occur when given together with trimethoprim dosages of these drugs should be modified and the patient monitored accordingly. 

Drug Interactions Zidovudine Probenecid Imipenem-cilastatin Dapsone Pentamidine Flucytosine Vincristine Vinblastine Adriamycin Amphotericin B TMP-SMX Other nucleoside analogues... 

DAPSONE ANTIVIRALS-ZIDOVUDINE Possible t adverse effects when co administered with zidovudine Uncertain possible T bioavailability of zidovudine Use with caution monitor for peripheral neuropathy... 

Lee BL, Safrin S, Makrides V, Gambertogho JG. Zidovudine, trimethoprim, and dapsone pharmacokinetic interactions in patients with human immunodeficiency virus infection. Antimicrob Agents Chemother 1996 40(5) 1231-6. 

Clinically important, potentially hazardous interactions with amphotericin B, dapsone, imipenem/cilastatin, zidovudine... 

On the other hand, probenecid increases the plasma level of acyclovir, allopurinol, barbiturate, benzodiazepines, clof-ibrate, dapsone, dyphylline, methotrexate, NSAIDs, penicillamine, sulfonylureas, and zidovudine. 

FIGURE 107 Patients with a clinical diagnosis of AIDS should undergo long-term therapy with zidovudine (AZT, 1200 mg q. 4 hrs). Acyclovir may potentiate the beneficial effects of AZT. In addition, patients should be treated prophylactically for Pneumocystis carinii pneumonia such regimens include sulfadoxine and pyrimethamine (Fansidar), dapsone, or aerosolized pentamidine. Dextran sulfate is also useful because it blocks the binding of HIV to target cells. 

Zidovudine is rapidly absorbed from the G1 tract with peak serum concentrations occurring within 30 to 90 minutes. It binds to plasma proteins to the extent of 35 to 40%. Zidovudine is rapidly metabolized in the liver to the inactive 3 -azido-3 -deoxy-5 -0-beta-D-glucopyranuronosylthymi-dine (GAZT), which has an apparent elimination half-life of 1 hour. Zidovudine undergoes glomerular filtration and active tubular secretion. Coadministration of zidovudine with agents such as dapsone, pentamidine, amphotericin B, flucytosine, vincristine, vinblastine, adriamycin, and interferon with potential to cause nephrotoxicity or cytotoxicity to hematopoietic elements, enhance its risk of adverse effects. Probenecid will inhibit the renal excretion of zidovudine. 

Dapsone 100 mg daily had no effect on the pharmacokinetics of a single 200-mg dose of zidovudine in 8 TUV-positive subjects. In a further study, which considered the safety of dapsone in combination with zidovudine, dapsone was shown to increase the risk of zidovudine-related blood dys-crasias. Therefore it would seem that dapsone and zidovudine can be given concurrently, but monitoring for an increase in adverse events would seem advisable. 

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