Drug Interaction Report

GENERALLY AVOID: Theoretically, H2 antagonists and proton pump inhibitors may decrease the gastrointestinal absorption of delavirdine. The proposed mechanism is a pH-dependent reduction in drug dissolution or absorption.

MANAGEMENT: While the clinical significance of this potential interaction is unknown, the manufacturer recommends against the chronic use of these drugs with delavirdine due to the risk of treatment failure and emergence of drug resistance associated with subtherapeutic levels of delavirdine.

H2 antagonists may reduce the clearance of nicotine. Cimetidine, 600 mg given twice a day for two days, reduced clearance of an intravenous nicotine dose by 30%. Ranitidine, 300 mg given twice a day for two days, reduced clearance by 10%. The clinical significance of this interaction is not known. Patients should be monitored for increased nicotine effects when using the patches or gum for smoking cessation and dosage adjustments should be made as appropriate.