Drug Interactions between Paxlovid and vemurafenib

Talk to your doctor before using ritonavir together with vemurafenib. Combining these medications may decrease the blood levels of ritonavir, which may reduce its effectiveness in treating your condition. At the same time, ritonavir may cause the blood levels of vemurafenib to rise. This may increase the risk of an irregular heart rhythm that may be serious, as well as other side effects of vemurafenib. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. You should seek immediate medical attention if you develop sudden dizziness, lightheadedness, fainting, shortness of breath, or fast or pounding heartbeats during treatment with these medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Vemurafenib may reduce the blood levels of nirmatrelvir, which may make the medication less effective in treating COVID-19 infection in some cases. Talk to your doctor if you have any questions or concerns. Your doctor may be able to prescribe alternatives that do not interact, or you may need a dose adjustment or more frequent monitoring to safely use both medications. Contact your doctor if your condition worsens or you develop new infections during treatment with these medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.