Rifabutin Dapsone

Deravirdine (Rescnptor) [Antiretroviral/NNRTI] Uses HIV Infxn Action Nonnucleoside RT inhibitor Dose 400 mg PO tid Caution [C, ] CDC recommends HIV-infected mothers not to breast-feed (transmission risk) w/ renal/hepatic impair Contra Use w/ drugs dependent on CYP3A for clearance (Table VI-8) Disp Tabs SE Fat redistribution, immune reconstitution synd, HA, fatigue, rash, T transaminases, N/V/D Interactions T Effects W/ fluoxetine T effects OF benzodiazepines, cisapride, clarithromycin, dapsone, ergotamine, indinavir, lovastatin, midazolam, nifedipine, quinidine, ritonavir, simvastatin, terfena-dine, triazolam, warfarin effects W/ antacids, barbiturates, carbamazepine, cimetidine, famotidine, lansoprazole, nizatidine, phenobarbital, phenytoin, ranitidine, rifabutin, rifampin effects OF didanosine EMS Use of benzodiazepines and CCBs should be avoided may cause a widespread rash located on upper body and arms OD May cause an extension of nl SEs symptomatic and supportive Deferasirox (Exjade) [Iron Chelator] Uses Chronic iron overload d/t transfusion in pts >2 y Action Oral iron chelator Dose Initial 20 mg/kg... 

Antimycobacterials and related drugs Aminosalicylic acid (PAS), Capreomycin, Clofazimine, Cycloserine, Dapsone, Ethambutol, Ethionamide, Isoniazid, Methaniazide, Protionamide, Pyrazinamide, Rifabutin, Rifampicin (Rifampin), Rifamycin, Rihipentine, Rihiximin... 

Winter TrqmeU CB, Slattery JT, Jacobson M, Greenspan DL, Hootai TM, Unadkat JD. The effect of claritiiFcniycin, fluconazole, and rifabutin on dapsone hydroxylamine formation in individuals with human immunodeficiency virus infection (AACTG 283). Clin Pharmacol 77 r (2004) 76,579-87. 

Twelve HIV-positive patients were given dapsone 100 mg daily for 2 weeks and then in random order either fluconazole 200 mg daily, rifabutin 300 mg daily or fluconazole with rifabutin, each for 2 weeks. Dapsone pharmaeokineties were unaffected by fluconazole. However, fluconazole inhibited the production of the jV-hydroxylamine metabolite of dapsone (AUC, urinary recovery, and formation clearance reduced by about 50%). ... 

Rifampicin and rifabutin increase the metabolism and clearance of dapsone. Rifampicin also increases the blood levels of the toxic hydroxylamine metabolite of dapsone. Similarly, rifabutin increased the formation of this metabolite, although increases in the AUC were not seen. 

Although there is less information, rifabutin appears to interact similarly to rifampicin. When dapsone is given with rifabutin, the dosage of dapsone may need to be increased, but this may increase exposure to the potentially toxic hydroxylamine metabolite. ... 

Rifampicin increases the urinary excretion of dapsone, lowers its serum ieveis and increases the risk of toxicity (methaemoglobinaemia). Simiiariy, rifabutin increases the clearance of dapsone, and may also increase its toxicity. 

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