Rifabutin Theophylline

Drugs that may affect fluconazole include cimetidine, hydrochlorothiazide, and rifampin. Drugs that may be affected by fluconazole include alfentanil, benzodiazepines, buspirone, carbamazepine, cisapride, oral contraceptives, corticosteroids, cyclosporine, haloperidol, HMG-CoA reductase inhibitors, losartan, nisoldipine, phenytoin, protease inhibitors, rifabutin, sirolimus, sulfonylureas, tacrolimus, theophylline, tolterodine, tricyclic antidepressants, vinca alkaloids, warfarin, zidovudine, and zolpidem. 

Drugs that may interact with rifabutin include the following Anticoagulants, azole antifungal agents, benzodiazepines, beta blockers, buspirone, corticosteroids, cyclosporine, delavirdine, doxycycline, hydantoins, indinavir, rifamycins, losartan, macrolide antibiotics, methadone, morphine, nelfinavir, quinine, quinidine, theophylline, aminophylline, tricyclic antidepressants, and zolpidem. 

Drugs that might be affected by lopinavir/ritonavir include ergot derivatives, oral contraceptives, antiarrhythmics, HMG-CoA reductase inhibitors, HIV protease inhibitors, atovaquone, calcium channel blockers, ketoconazole, itraconazole, pimozide, cisapride, clarithromycin, disulfiram, metronidazole, immunosuppressants, midazolam, triazolam, narcotic analgesics, rifabutin and rifabutin metabolite, sildenafil, warfarin, bupropion, clozapine, desipramine, piroxicam, quinidine, theophylline, and zolpidem. 

T effects OF amiodarone, astemizole, atorvastadn, barbiturates, bepridil, bupropion, cerivastatin, cisapride, clorazepate, clozapine, clarithromycin, desipramine, diazepam, encainide, ergot alkaloids, estazolam, flecainide, flurazepam, indinavir, ketoconazole, lovastatin, meperidine, midazolam, nelfinavir, phenytoin, pimozide, piroxicam, propafenone, propoxyphene, quinidine, rifabutin, saquinavir, sildenafil, simvastatin, SSRIs, TCAs, terfenadine, triazolam, troleandomycin, zolpidem X effects W/ barbiturates, carbamazepine, phenytoin, rifabutin, rifampin, St. John s wort, tobacco X effects OF didanosine, hypnotics, methadone, OCPs, sedatives, theophylline, warfarin EMS T Effects of amiodarone, diazepam, midazolam and BBs, may need X- doses concurrent use of Viagra-type drugs can lead to hypotension X- effects of warfarin concurrent EtOH use can T adverse effects T glucose ODs May cause an extension of adverse SEs symptomatic and supportive Rivasrigmine (Exelon) [Cholinesterase Inhibitor/Anri ... 

Rifampicin (rifampin) lowers the serum levels of theophylline, but rifabutin appears to have little effect. Isoniazid may decrease or increase theophylline clearance and may increase theophylline levels. An isolated report describes theophylline toxicity one month after a patient started to take theophyUine with isoniazid. Isoniazid and rifampicin increased theophylline clearance during the initial few days of tuberculosis treatment in one study, but there is some evidence that it decreases it within 4 weeks in another. 

Rifampicin is a potent liver enzyme inducer, which increases the metabolism of the theophylline, thereby increasing its clearance and reducing its serum levels. It has been suggested that isoniazid inhibits the metabolism of theophylline by the liver, thereby reducing its clearance and increasing its plasma levels. Rifabutin is a much less potent liver enzyme inducer than rifampicin, and consequently has less of an effect on theophylline metabolism. 

The effects of rifabutin are considerably less than those of rifampicin, with the one available study showing no significant interaction. On the basis of this, no special precautions appear to be necessary, but it may be prudent to monitor the efficacy of theophylline on concurrent use. 

Gillum JG, Sesler JM, Bruzzese VL, Israel DS, Polk RE. Induction of theophylline clearance by rifampin and rifabutin in healthy male volunteers. Antimicrob Agents Chemother (199Q 40, 1866-9. 

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