No pharmaceutical opinion available for this interaction.
Rifampin increases the metabolism (CYP 3A4) and decreases the plasma concentration of Atazanavir / ritonavir.
3A4, P-gp/3A4 > 2D6, P-gp
Ritonavir: 1A2, 2C9, 2C19, UGT, 2B6, 3A4 (auto-induction)
3A4, UGT1A1, P-gp E et 2C8/3A4 > 2D6 > 2A6, 2E1, P-gp, MRP2
Possible decrease of clinical efficacy.
Risk of a possible development of resistance to antiretroviral class.
1A2, 2C9, 2E1, P-gp
1A2, 2C9, 2C19, 3A4-7, UGT 1A1, P-gp
Increased risk of hepatotoxicity.
Choose an alternative.
Rifabutin either 150 mg QD, every 2 days or 3 times a week (see rifabutin with PIs) or choose an antibiotic that does not interact with PIs.
|600 mg||600 mg**|
|400/200 mg||300 mg**/100 mg**|
|+ 10% *|
|- 60% *|
Ref #1634: Rifampin and desacetyl rifampin exposures were comparable across different regimens of ATV/RTV, but were ~1.6 to 2.5 times higher that with rifampin alone.
* Compared to atazanavir 400 mg daily.
Ref #2324 : Study with 10 patients HIV negative receiving ATV 300 mg BID (stade 1) + Rifampin and ATV 400 mg + RIF 600 mg QD (stade 2) vs. ATV 300 mg BID. Despite the administration twice a day of atazanavir (300 mg BID), the Cmin of atazanavir was 44 ng/ml for patients receiving ATV 300 BID + RIF and 113 ng/ml for patients receiving ATV 400 + RIF compared to 811 ng/ml for patients receiving atazanavir 300 mg BID without rifampin.
Ref #2323 : Study with 71 patients HIV negative receiving 300/100 mg QD of ATV/r vs. ATV/r + RIF 300/100/600 mg vs. ATV/r + RIF 300/200/600 mg vs. ATV/r + RIF 400/200/600 mg.
Results : Cmin of 707, 3 ng/mL in patients under ATV/r vs. 18.1 in ATV/r/RIF 300/100/600 mg vs. 42,7 in ATV/r/RIF 300/200/600 mg vs. 52,9 in ATV/r/RIF 400/200/600 mg.
Réf #2396: Study with 3 stages :
During the 1st stage *, rifampicin 600 mg once a day during 8 days. Stage 2 **: Rifampin 600 mg + Atazanavir/ritonavir 300/100 mg BID during 11 days. Stage 3: Increase in dosage of atazanavir/ritonavir 400/100 mg BID.
Following this increase in dosage, 3 patients had an increase of transaminases and vomiting. The treatment had to be stopped.
Co-administration of rifampicin 600 mg QD with protease inhibitors such as lopinavir/ritonavir, darunavir/ritonavir and atazanavir alone also causes a decrease in AUC and Cmin of approximately 75% to 80%.
Ref #3116 : To increase the chance of achieving therapeutic serum levels and reduce the development of resistance and treatment failures some experts, as well as the CDC, recommend a 150mg QD dose. See rifabutin + PIs.