Tenofovir Disoproxil Fumarate + Lamivudine = Unknown or no reaction

Effect on Concentration

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

Pharmacologic Effects

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

Interaction History

N/A

Last Updated 19-Jul-2018

Summary

Sources

Tenofovir Disoproxil Fumarate versus Lamivudine ^

Study Design

This was a prospective evaluation of intracellular concentrations and pharmacokinetics of tenofovir diphosphate (TFV-DP), carbovir triphosphate (CBV-TP), and lamivudine triphosphate (3TC-TP) in patients on triple-nucleoside regimens. Fifteen patients on a stable TDF plus ABC plus a third nucleoside reverse transcriptase (RT) inhibitor (3TC [n = 13], stavudine [n = 2]) regimen discontinued TDF or ABC, replacing it with a nonnucleoside RT inhibitor or protease inhibitor. Peripheral blood mononuclear cells were collected after the last dose of TDF or ABC at baseline and over 12 to 96 hours as well as at days 14 and 28 after discontinuation. Nucleotide concentrations were measured directly using liquid chromatography with tandem mass spectrometry; changes after ABC or TDF discontinuation would provide evidence of an intracellular drug interaction.

Study Results

Summary of PK parameters for lamivudine in the presence of tenofovir DF include the following: Cmax decreased 24% (12%-34%), and there was no change in AUC or Cmin. The effects of coadministration on tenofovir was not described.

Study Conclusions

3TC-TP concentrations were not significantly different based on the drug discontinued (P = 0.62) or pharmacokinetic visit (P = 0.14), with similar values at baseline or 1 month after the regimen change (9380 and 8760 fmol/106 cells [n = 13]) by 2-way ANOVA. Significant interpatient variability was observed acrossvisits (P < 0.0001), with absolute and median 3TC-TP concentration variabilities of 19.8-fold and 1.64-fold, respectively. Within an individual patient, 3TC-TP levels exhibited a median 2.15-fold (1.25-fold to 11.2-fold, minimum-maximum values) intrapatient fluctuation across visits

References

Hawkins T, Veikley W, Claire III RLS, Guyer B, Clark N, Kearney BP. Intracellular pharmacokinetics of tenofovir diphosphate, carbovir triphosphate, and lamivudine triphosphate in patients receiving triple-nucleoside regimens. j. Journal Of Acquired Immunodeficiency Syndromes. 2005; 4: 406-411.