Abacavir + Tenofovir Disoproxil Fumarate = Unknown or no reaction

Effect on Concentration

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

Pharmacologic Effects

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

Interaction History

N/A

Last Updated 19-Jul-2018

Summary

Sources

Abacavir versus Tenofovir Disoproxil Fumarate ^

Study Design

In a study by Kearney, et al1, a single dose of abacavir 300 mg was dosed alone and with tenofovir DF 300 mg to a subset of patients participating in a ddI drug interaction study. Due to the risk of ABC hypersensitivity and safety reasons, only the PK of single doses of abacavir were evaluated. Abacavir was administered alone and following multiple doses of TDF with food at tenofovir steady state to maximize the interaction potential on abacavir. Study drugs were administered within 5 minutes of completion of a standardized light meal. Blood sampling was performed over 24 hours. Tenofovir and abacavir concentrations in plasma were determined by validated assays.

Study Results

Single dose ABC Pharmacokinetics Abacavir PK Parameter ABC Alone ABC + TDF % Mean Ratio (90% CI) AUC 5.67 (35.5) 6.01 (32.9) 110 (102, 118) Cmax 1.77 (39.2) 1.95 (35) 112 (98.7, 126) T ½ 1.21 (1 – 1.36) 1.26 (1.15 – 1.38) NA Tmax 1.5 (1.5-2) 1.5 (1.49 – 2) NA Steady State Tenofovir Pharmacokinetics with ABC Tenofovir PK Parameter TDF Alone TDF + ABC % Mean Ratio (90% CI) AUC 2620 (30.5) 2690 (26) 104 (85.7 – 126) Cmax 296 (26.7) 276 (33.3) 92.2 (76 – 112) Cmin 58.2 (34) 55.3 (29.2) NA Tmax 1.5 (1-2) 1.75 (1.25 – 2) NA When coadministered with tenofovir DF, mean abacavir AUC was equivalent and mean Cmax was 12% higher compared with values when abacavir was administered alone. Mean tenofovir AUC and Cmax were similar to historical data.

Study Conclusions

: Kearney, et al, concluded that abacavir PK were not significantly affected by TDF. Tenofovir PK with a single dose of abacavir was similar to historical data for TDF. As these drugs had been shown to have additive antiviral effects (in vitro), this data did not suggest an explanation to the suboptimal clinical outcome of studies using TDF with lamivudine and abacavir.

References

Kearney BP. The pharmacokinetics of abacavir, a purine nucleoside analogue, are not affected by tenofovir df. Interscience Conference On Antimicrobial Agents And Chemotherapy. Chicago, IL, USA. 43; September 2003.