NRTIs Methadone

Drugs that may be affected by peginterferon alfa-2a include theophylline, methadone, and NRTIs (eg, didanosine, zidovudine, stavudine). 

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). 

Of 80 injecting drug users who took two NRTIs + nevirapine (NNRTI), 20 discontinued treatment and 20 had treatment failures (5). Adverse events led to withdrawal of therapy in 10 patients eight had a rash (in one case Stevens-Johnson syndrome) one had liver failure thought to be unrelated to the drugs and one had general intolerance. Two patients taking methadone had opioid withdrawal symptoms, presumably due to induction of methadone metabolism by nevirapine. 

---