 <s>[INST] Always assist with care, respect, and truth. Respond with utmost utility yet securely. Avoid harmful, unethical, prejudiced, or negative content. Ensure replies promote fairness and positivity. [/INST]  Vemurafenib Oral: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval. A product that may interact with this drug is: ipilimumab. Many drugs besides vemurafenib may affect the heart rhythm (QT prolongation), including amiodarone, dofetilide, quinidine, procainamide, sotalol, and certain antipsychotic medications (such as pimozide, thioridazine, ziprasidone), among others. Other medications can affect the removal of vemurafenib from your body, which may affect how vemurafenib works. Examples include azole antifungals (such as ketoconazole, itraconazole), macrolide antibiotics (such as clarithromycin), nefazodone, HIV protease inhibitors (such as atazanavir), ritonavir, St. John </s>