Raltegravir + Efavirenz = Precautionary

Effect on Concentration

Raltegravir
Decrease
Applies within class?
No
Efavirenz
Unknown
Applies within class?
No

Pharmacologic Effects

Raltegravir
Effect
N/A
Applies within class?
No
Efavirenz
Effect
N/A
Applies within class?
No

Interaction History

N/A

Last Updated 22-Nov-2022

Summary

Sources

Raltegravir vs efavirenz or ritonavir ^

Study Design

14 male, HIV-negative healthy subjects were administered a single dose of raltegravir 400 mg followed by a 4-day or longer washout interval (Period 1). Ritonavir 100 mg was then administered twice daily for 16 days (Period 2). A single dose of raltegravir 400 mg was administered with the morning dose of ritonavir on day 14 of period 2. Raltegravir PK sampling occurred 16 times over 48 hours beginning with each raltegravir dose.All doses were administered with a moderate-fat meal, as is recommended with ritonavir. Raltegravir doses were placebo-controlled, and ritonavir was administered open-label.

Study Results

In the 9 patients who received raltegravir, and not placebo, efavirenz decreased geometric mean rations of raltegravir AUC, Cmax and trough concentration by 36%, 36% and 21% respectively. Only the decrease in AUC reached statistical significance (p=0.006).

Study Conclusions

References

Marian Iwamoto, Larissa A Wenning, Amelia S Petry, Martine Laethem, Marina De_Smet, James T Kost, Sheila A Breidinger, et al. Minimal effects of ritonavir and efavirenz on the pharmacokinetics of raltegravir. Antimicrobial Agents And Chemotherapy. 2008; 12: 4338-4343.