Delavirdine receptor antagonists

Drugs that may affect fosamprenavir include antacids, carbamazepine, delavirdine, dexamethasone, histamine H2-receptor antagonists, HMG-CoA reductase inhibitors,... 

Delavirdine Due to its shorter tj, d rapid emergence of resistance, delavirdine is the least used of the NNRTIs. Its absorption is best at acid pH and may be decreased by histamine Hj receptor antagonists or proton pump inhibitors. It is cleared predominantly by CYP3A4 and has an elimination tj 6 hours. It should be avoided with CYP3A4 substrates with a narrow therapeutic index and not combined with potent inducers of CYP3A4 (e.g., carbamazepine, phenobarbital, phenytoin, rifabutin, and rifampin). 

Antacids roughly halve the AUC of delavirdine, and the 112-receptor antagonists or proton pump inhibitors would be expected to interact similarly. Aluminium/magnesium antacids do not interact to a clinically relevant extent with efavirenz or nevirapine, and famotidine does not alter the absorption of efavirenz. 

Furthermore, delavirdine (Rescriptor) is a novel HIV-1 reverse transcriptase inhibitor for HIV-positive individuals and zafirlukast (Accolate) is an anti-asthma drug. The anti-emetics ramosetron (Nasea) and dolasetron (Anzemet) are potent and highly selective 5-HTj receptor antagonists for die treatment of chemotherapy-induced nausea and vomiting. 

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