Liverpool HIV Interactions

Potential Interaction

Ritonavir (RTV)

_ZZDarunavir

Quality of Evidence: Low

Summary:

Darunavir should only be used in combination with 100 mg of ritonavir as a pharmacokinetic enhancer. Increasing the dose of ritonavir did not significantly affect darunavir concentrations and is not recommended.

Description:

Darunavir has been approved for use with ritonavir as a pharmacokinetic enhancer at the noted doses:
Darunavir 600 mg twice daily with ritonavir 100 mg twice daily in antiretroviral treatment (ART) experienced patients.
Darunavir 800 mg once daily with ritonavir 100 mg once daily may be used in some ART experienced patients. (Refer to the darunavir SmPC for further information on once daily dosing in ART experienced patients.)
Darunavir 800mg once daily with ritonavir 100 mg once daily in ART-naïve patients.

Coadministration of darunavir (600 mg single dose) and ritonavir (100 mg twice daily) increased darunavir AUC by 14-fold. Ritonavir increases the serum levels of darunavir as a result of CYP3A inhibition. Darunavir must be given with ritonavir to ensure its therapeutic effect. Ritonavir doses higher than 100 mg twice daily have not been studied with darunavir. For further information, refer to the Summary of Product Characteristics for Prezista.

Norvir Summary of Product Characteristics, AbbVie Ltd, September 2016.

Coadministration is expected to increase darunavir concentrations. See the complete Prescribing Information for darunavir for details on co-administration with ritonavir.
Norvir Prescribing Information, AbbVie Inc, December 2016.

Darunavir must always be given orally with low dose ritonavir as a pharmacokinetic enhancer. Increasing the dose of ritonavir did not significantly affect darunavir concentrations and is not recommended. The overall pharmacokinetic enhancement effect by ritonavir was an approximate 14-fold increase in the systemic exposure of darunavir when a single dose of 600 mg darunavir was given orally in combination with ritonavir at 100 mg twice daily Therefore, darunavir must only be used in combination with low dose ritonavir as a pharmacokinetic enhancer.
Prezista Summary of Product Characteristics, Janssen-Cilag Ltd, June 2012.

Darunavir is primarily metabolized by CYP3A. Ritonavir inhibits CYP3A, thereby increasing the plasma concentrations of darunavir. When a single dose of 600 mg darunavir was given orally in combination with 100 mg ritonavir twice daily, there was an approximate 14-fold increase in the systemic exposure of darunavir. Therefore, darunavir should only be used in combination with 100 mg of ritonavir to achieve sufficient exposures of darunavir.
Prezista Prescribing Information, Tibotec Inc, June 2012.

View all available interactions with Ritonavir (RTV) by clicking here.