Voriconazole/Atazanavir; Cobicistat; Ritonavir Interactions
This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.
Medical warning:
Serious. These medicines may interact and cause very harmful effects. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.
How the interaction occurs:
Voriconazole may slow down how quickly your liver processes cobicistat. The effect of cobicistat on voriconazole is unknown.Ritonavir may speed up how quickly your liver processes voriconazole, and voriconazole may speed up how quickly your liver processes ritonavir.
What might happen:
If voriconazole is used with cobicistat, the amount of cobicistat in your blood may increase and cause side effects, including kidney problems.If voriconazole is used with ritonavir, voriconazole and ritonavir may not work as well.
What you should do about this interaction:
Let your healthcare professionals (e.g. doctor or pharmacist) know that you are taking these medicines together. Your doctor may want to change your medicines.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.
- 1.Vfend (voriconazole) US prescribing information. Pfizer Inc. October, 2022.
- 2.Norvir (ritonavir) US prescribing information. Abbott Laboratories December, 2019.
- 3.Tybost (cobicistat) US prescribing information. Gilead Sciences, Inc. September, 2021.
- 4.Reyataz (atazanavir sulfate) US prescribing information. Bristol-Myers Squibb Company November, 2023.
- 5.Panel on Antiretroviral Guidelines for Adults and Adolescents. Guidelines for the use of antiretroviral agents in adults and adolescents Living with HIV. Department of Health and Human Services. Available at https://clinicalinfo.hiv.gov/en/guidelines/adult-and-adolescent-arv/whats- new-guidelines June 13, 2021.
- 6.Paxlovid (nirmatrelvir tablets and ritonavir tablets) Canadian Product Monograph. Pfizer Canada ULC December 8, 2022.
- 7.Mikus G, Schowel V, Drzewinska M, Rengelshausen J, Ding R, Riedel KD, Burhenne J, Weiss J, Thomsen T, Haefeli WE. Potent cytochrome P450 2C19 genotype-related interaction between voriconazole and the cytochrome P450 3A4 inhibitor ritonavir. Clin Pharmacol Ther 2006 Aug;80(2):126-35.
Selected from data included with permission and copyrighted by First Databank, Inc. This copyrighted material has been downloaded from a licensed data provider and is not for distribution, except as may be authorized by the applicable terms of use.
CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.