Atazanavir + Rifampin = Prohibited

Effect on Concentration

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

Pharmacologic Effects

Atazanavir
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 rifampicin and ritonavir‐boosted atazanavir in HIV‐infected patients. ^

Study Design

Authors performed a prospective study in three HIV‐infected patients with TB treated with a rifampicin‐containing regimen (rifampicin 600 mg per day) and antiretroviral therapy including only nucleoside reverse transcriptase inhibitors (NRTIs) plus atazanavir 300 mg once a day (qd) and ritonavir 100 mg qd, to evaluate whether the inducing effect of rifampicin on the drug‐metabolizing enzyme cytochrome P450 (CYP) 3A4 could be overcome by the inhibitory effect of ritonavir. A complete pharmacokinetic evaluation of the steady‐state concentrations of atazanavir and ritonavir was performed.

Study Results

In all three cases, more than 50% of the time the atazanavir level was below the minimum recommended trough plasma level (150 ng/mL according to current pharmacokinetic guidelines) to inhibit HIV wild‐type replication.

Study Conclusions

These results strongly indicate that the administration of rifampicin with a combination of atazanavir 300 mg qd plus ritonavir 100 mg qd must be avoided because subtherapeutic concentrations of atazanavir are produced.

References

Mallolas J, Sarasa M, Nomdedeu M, Soriano A, Lopez-Pua Y, Blanco JL, Gatell JM. Pharmacokinetic interaction between rifampicin and ritonavir‐boosted atazanavir in hiv‐infected patients. Hiv Medicine. 2007; 2: 131-134.