Methadone levels reduced moderately by rilpivirine

1 June 2010. Related: Conference reports, PK and drug interactions, PK Workshop 11th 2010.

www.hiv-druginteractions.org

The effect of TMC278 (25 mg once daily) on the pharmacokinetics and pharmacodynamics of methadone was studied in 13 HIV negative volunteers stable on methadone maintenance therapy (60-150 mg/day).  TMC278 decreased the AUC, Cmax and Cmin of active R-methadone by 16%, 14% and 22%, respectively. Decreases were also seen in the AUC (16%), Cmax (13%) and Cmin (21%) of inactive S-methadone.  Exposure of TMC278 in the presence of methadone was within the expected range. No signs of opiate withdrawal were observed.

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Although no a-priori dose adjustment of methadone is required, clinical monitoring for withdrawal symptoms is recommended as some patients may require dose adjustment.

Ref: Crauwels HM et al. Pharmacokinetic interaction study between TMC278, a next-generation NNRTI and methadone. 11th PK Workshop, 2010. Abstract 33.