Samtidig administration af 700 mg fosamprenavir og 100 mg ritonavir 2 gange daglig og metadon en gang daglig (≤ 200 mg) i 14 dage reducerede AUC( 0- τ) og Cmax for den aktive (R -) enantiomer af metadon med henholdsvis 18% og 21%.
Methadone: co-administration of fosamprenavir 700 mg and ritonavir 100 mg twice daily with methadone once daily (≤ 200 mg) for 14 days decreased the active (R-) methadone enantiomer AUC(0- τ) and Cmax by 18% and 21% respectively.