Methadone Atazanavir

The buffer in didanosine tablets and powder interferes with absorption of indinavir, delavirdine, atazanavir, dapsone, itraconazole, and fluoroquinolone agents therefore, administration should be separated in time. Serum levels of didanosine are increased when -administered with tenofovir or ganciclovir, and are decreased by atazanavir, delavirdine, ritonavir, tipranavir, and methadone (Table 49-4). 

Methadone serum levels can be reduced by amprenavir, nelfina-vir, lopinavir/ritonavir, saquinavir/ritonavir, tipranavir/ritona-vir, and possibly ritonavir. In addition, amprenavir levels may be reduced by methadone. No interaction appears to occur between methadone and indinavir, or possibly atazanavir or saquinavir, alone. 

Atazanavir, given for 14 days, had little effect on the steady-state pharmacokinetics of methadone in 16 patients treated for opiate addiction, and symptoms of opiate withdrawal or excess were not detected. ... 

Indinavir appears not to internet with methadone, and very limited evi-denee suggests that atazanavir and saquinavir alone do not interact either. 

The interaction of methadone (20-175 mg/ day) and atazanavir/ritonavir (300/100 mg/ day) has been investigated in 24 HIV-1-positive patients, who were randomized to methadone or just the antiretroviral drugs [125. The dose of methadone correlated significantly with the maximum plasma concentration of atazanavir, resulting in a reduced plasma concentration. 

Haberl A, Moesch M, Nisius G, Stephan C, Bickel M, Khaykin P, Kurowski M, Brodt R, Von Hentig N. Atazanavir plasma concentrations are impaired in mV-l-infected adults simultaneously taking a methadone oral solution in a once-daily observed therapy setting. Eur J Clin Pharmacol 2010 66 375-81. 

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