Decreased methadone effect after ritonavir initiation

Pharmacotherapy. 2000 Jan;20(1):93-4. doi: 10.1592/phco.20.1.93.34654.

Abstract

Combination antiretroviral therapy including protease inhibitors such as ritonavir has added significant potency to therapy for human immunodeficiency viral (HIV) infection as well as substantial drug-drug interactions. Methadone metabolism is affected by cytochrome P450 (CYP) 3A4 inhibitors or inducers. Because ritonavir can induce CYP3A, it can decrease methadone plasma levels. An HIV-infected patient receiving methadone maintenance experienced withdrawal symptoms after ritonavir, saquinavir, and stavudine were added to his regimen; the most likely cause was ritonavir.

Publication types

  • Case Reports

MeSH terms

  • Analgesics, Opioid / metabolism*
  • Anti-HIV Agents / adverse effects*
  • Anti-HIV Agents / therapeutic use
  • Diagnosis, Differential
  • Drug Interactions
  • Drug Therapy, Combination
  • HIV Infections / complications
  • HIV Infections / drug therapy*
  • HIV Protease Inhibitors / adverse effects*
  • HIV Protease Inhibitors / therapeutic use
  • Humans
  • Male
  • Methadone / metabolism*
  • Middle Aged
  • Ritonavir / adverse effects*
  • Ritonavir / therapeutic use
  • Saquinavir / adverse effects
  • Saquinavir / therapeutic use
  • Stavudine / adverse effects
  • Stavudine / therapeutic use
  • Substance Withdrawal Syndrome / diagnosis
  • Substance-Related Disorders / complications
  • Substance-Related Disorders / rehabilitation

Substances

  • Analgesics, Opioid
  • Anti-HIV Agents
  • HIV Protease Inhibitors
  • Stavudine
  • Saquinavir
  • Ritonavir
  • Methadone