Methadone antiretroviral drugs

Drugs that may affect didanosine include allopurinol, methadone, and ganciclovir. Drugs that may be affected by didanosine include ganciclovir, antacids, antifungal agents, antiretroviral drugs, fluoroquinolones, and stavudine. 

A newborn girl born of an HIV-positive mother who took antiretroviral drugs and methadone during pregnancy developed a methadone abstinence syndrome at day 7 (43). She was HIV-negative and was treated symptomatically for 15 days with chlorpromazine. The platelet count was 1049 x 109/1 on day 17 and fell progressively to 290 x 109/1 at 8 weeks. The authors suggested that the thrombocytosis had been secondary to intrauterine methadone exposure. 

In a prospective study of 54 patients taking antiretroviral drugs who also took methadone and a further 154 patients who did not take methadone there were similar clinical, virological, and immunological outcomes after 12 months (52). These results support the usefulness of methadone in the management of intravenous drug users with HIV infection. 

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. 

The interaction of buprenorphine with antiretroviral drugs has been reviewed [207 ]. Buprenorphine has fewer interactions with antiretroviral drugs than methadone and is associated with public health benefits, such as reduced risky behavior and spread of HIV. 

Antiretroviral drugs In 12 healthy HIVnegative volunteers, nelflnavir reduced plasma methadone concentrations by 40-50%, increased its renal clearance, and increased hepatic metabolism, extraction, and clearance [96 ]. 

Drug-drug interactions Eighteen patients who were given telaprevir and methadone showed no decrease in methadone concentration or any signs of opiate withdraw [55 ]. A meffl-analysis of FAERS from 1997 to 2011 showed increased risk of cardiac arrhythmias in patients on antiretroviral drugs and methadone [43 ]. 

Moreno A, Perez-Elias MJ, Casado JL, Munoz V, Antela A, Dronda F, Navas E, Moreno S. Long-term outcomes of protease inhibitor-based therapy in antiretroviral treatment-naive HIV-infected injection drug users on methadone maintenance programmes. AIDS 2001 15(8) 1068-70. 

Many recreational drugs such as benzodiazepines, amphetamines, and opioids are also metabolized by the liver. Although information is scant about the clinical significance and interactions between these drugs and antiretroviral agents, unintentional overdoses with methamphetamine and gamma hydroxybutyrate have been reported in patients using Pis, particularly ritonavir. Pis and NRTIs may alter metabohsm of methadone and precipitate opioid withdrawal (McCance-Katz et al., 2003). 

Drug mteractions between opioids and antiretroviral medications interaction between methadone, LAAM, andnelfinavir./lm (2004) 13,163 -80. 

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