Drug Interactions between efavirenz and mavacamten

Grapefruit juice may increase the blood levels of mavacamten and increase the risk of heart failure, a condition where the heart is unable to pump blood adequately to meet the body's needs. Your risk may be further increased if you develop a serious infection or irregular heartbeat during treatment with mavacamten. You should avoid the consumption of grapefruit and grapefruit juice while taking this medication. Talk to your doctor if you have any questions or concerns. You should seek medical attention if you experience signs and symptoms of heart failure such as shortness of breath, chest pain, fatigue, swelling in your legs, palpitations, or rapid weight gain. 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.

Taking efavirenz with food increases the amount of medicine in your body, which may increase the frequency of side effects. You should take efavirenz once a day on an empty stomach, preferably at bedtime. Taking it at bedtime may make some side effects such as dizziness, trouble sleeping, drowsiness, trouble concentrating, and/or unusual dreams less bothersome. However, these symptoms may be more severe if efavirenz is used with alcohol or mood-altering (street) drugs. You should avoid driving or operating hazardous machinery until you know how the medication affects you. 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.