Oxymorphone extended release does not affect CYP2C9 or CYP3A4 metabolic pathways

  • Adams M
  • Pieniaszek H
  • Gammaitoni A
 et al. 
  • 17


    Mendeley users who have this article in their library.
  • 61


    Citations of this article.


Two 14-day, randomized, open-label, parallel-group studies examined the effects of extended-release (ER) oxymorphone on CYP2C9 or CYP3A4 metabolic activities in healthy subjects. On days -1, 7, and 14, subjects received either a CYP2C9 probe (tolbutamide 500 mg) or CYP3A4 probes (midazolam and [14C N-methyl]-erythromycin for the erythromycin breath test). Subjects were randomized to 5 groups: high-dose oxymorphone ER (3 x 20 mg q12h) + naltrexone (50 mg q24h); low-dose oxymorphone ER (10-20 mg q12h); rifampin (2 x 300 mg q24h), an inducer of CYP2C9 and CYP3A4 activities; naltrexone (50 mg q24h); or CYP probes alone (controls). Probe metabolism was significantly altered by rifampin on days 7 and 14 (P < .05), whereas probe metabolism was not significantly affected by low-dose oxymorphone ER or by high-dose oxymorphone ER plus naltrexone. Oxymorphone ER exhibits a minimal potential for causing metabolic drug-drug interactions mediated by CYP2C9 or CYP3A4.

Author-supplied keywords

  • CYP2C9
  • CYP3A4
  • Drug interactions
  • Opioid
  • Oxymorphone extended release

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document


  • Michael Adams

  • Henry J. Pieniaszek

  • Arnold R. Gammaitoni

  • Harry Ahdieh

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free