Effect of antacids and ranitidine on the single-dose pharmacokinetics of fosamprenavir.

Single doses of MAALOX TC and ranitidine were administered separately with 1,400 mg of fosamprenavir (FPV). MAALOX TC decreased the area under the concentration-time curve from 0 to 24 h (AUC(0-24)) for plasma amprenavir (APV) by 18% and the maximum concentration of drug in serum (C(max)) by 35%; the plasma APV concentration at 12 h (C(12)) increased by 14%. Ranitidine at 300 mg decreased the AUC(0-24) for plasma APV by 30% and C(max) by 51%; C(12) was unchanged. FPV may be coadministered with antacids without concern and without separation in dosing; however, caution is recommended when FPV is coadministered with histamine(2)- receptor antagonists or proton pump inhibitors.