Tenofovir Disoproxil Fumarate + Methadone = Unknown or no reaction

Effect on Concentration

Tenofovir Disoproxil Fumarate
No change
Applies within class?
No
Methadone
No change
Applies within class?
No

Pharmacologic Effects

Tenofovir Disoproxil Fumarate
Effect
N/A
Applies within class?
No
Methadone
Effect
N/A
Applies within class?
No

Interaction History

N/A

Last Updated 19-Jul-2018

Summary

Sources

Tenofovir Disoproxil Fumarate versus Methadone ^

Study Design

The effect of coadministration of tenofovir DF with methadone was assessed in 13 HIV-negative volunteers receiving long-term methadone maintenance. [51] Study participants were required to have at least 2 weeks of documented methadone administration to ensure a stable dosage at baseline. Pharmacokinetics of total methadone and ( R)- (the most active form) and ( S)-methadone were determined at baseline (without tenofovir DF) and on study day 14 (with tenofovir DF). Tenofovir pharmacokinetics were determined in serum on study day 14 and compared with historical data. In addition to pharmacokinetic assessments, subjects were evaluated for signs and symptoms of methadone toxicity and/ or opioid withdrawal before and during coadministration of tenofovir DF.

Study Results

Following 14 days of combined administration, geometric mean R-methadone systemic exposures, AUCss and Cmax, differed by 5% or less when methadone was dosed with tenofovir DF. Similar results were observed for S-methadone and for total methadone. Both AUCss and Cmax met the strict criteria for bioequivalence between the two study periods for total, R-, and Smethadone, indicating a lack of drug interaction when tenofovir DF was coadministered with methadone. Tenofovir pharmacokinetics in subjects receiving methadone were consistent with historical data from healthy volunteers and HIV-infected patients. None of the study participants experienced symptoms of opioid withdrawal or toxicity, indicating the lack of a pharmacodynamic effect of tenofovir DF on methadone.

Study Conclusions

The authors concluded that coadministration of tenofovir and methadone did not alter the pharmacokinetics or pharmacydynamics of total, R or S methadone. Tenofovir DF may be given as part of an antiretroviral regimen in patients receiving methadone maintenance therapy.

References

Smith PF, Kearney BP, Liaw S, Cloen D, Bullock JM, Haas CE, Flaherty JF. Effect of tenofovir disoproxil fumarate on the pharmacokinetics and pharmacodynamics of total, r‐, and s‐methadone. Pharmacotherapy. 2004; 8: 970-977.