Indinavir + Rifampin = Prohibited

Effect on Concentration

Indinavir
Decrease
Applies within class?
No
Rifampin
No change
Applies within class?
No

Pharmacologic Effects

Indinavir
Effect
N/A
Applies within class?
No
Rifampin
Effect
N/A
Applies within class?
No

Interaction History

N/A

Last Updated 02-Jul-2018

Summary

Sources

Pharmacokinetic interaction between rifampin and the combination of indinavir and low-dose ritonavir in HIV-infected patients ^

Study Design

A prospective, controlled, multiple-dose study involving 6 HIV-infected patients receiving a combination of indinavir (800 mg) and ritonavir (100 mg) twice a day was performed to evaluate whether the inducing effect of rifampin on the drug-metabolizing enzyme cytochrome P450 (CYP) 3A4 could be overcome by the inhibitory effect of ritonavir. Pharmacokinetic evaluations of steady-state concentrations of indinavir and ritonavir were performed before and after administration of rifampin (300 mg every day for 4 days).

Study Results

An 87% reduction (from 837 to 112 ng/mL) in median indinavir and a 94% reduction (from 431 to 27 ng/mL) in median ritonavir concentrations were seen 12 h after the last dose of rifampin was administered (P = .031).

Study Conclusions

These results strongly indicate that the administration of rifampin with a combination of indinavir (800 mg) and ritonavir (100 mg) could lead to subtherapeutic concentrations of indinavir.

References

Justesen US, Anderson AB, Klitgaard NA, Brosen K, Gerstoft J, Pedersen C. Pharmacokinetic interaction between rifampin and the combination of indinavir and low-dose ritonavir in hiv-infected patients. Clinical Infectious Diseases. 2004; 3: 426-429.