Drug Interaction Report

Using cobimetinib together with chloroquine may increase the risk of serious and potentially irreversible eye problems. You will need to have regular eye exams during your treatment with chloroquine. Talk to your doctor if you have any questions or concerns. Your doctor may already be aware of the risks but has determined that this is the best course of treatment for you and has taken appropriate precautions and is monitoring you closely for any potential complications. If you notice any changes in your vision, like blurred vision, floaters, or flashes of light, you should seek immediate medical attention during treatment with these medications, whether together or individually. 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.

You may want to limit your consumption of grapefruit or grapefruit juice during treatment with chloroquine. Grapefruit juice can significantly increase the blood levels and effects of chloroquine, which may result in an irregular heart rate or other conduction disturbances. Hydroxychloroquine should also be taken with food or milk to reduce the incidence of stomach upset. Talk to your doctor if you have any questions or concerns. You should seek immediate medical attention if you develop sudden dizziness, lightheadedness, fainting, shortness of breath, or heart palpitations during treatment with chloroquine. 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.

Grapefruit juice may increase the blood levels and effects of certain medications such as cobimetinib. You may want to limit your consumption of grapefruit and grapefruit juice during treatment with cobimetinib. However, if you have been regularly consuming grapefruit or grapefruit juice with cobimetinib, do not alter the amounts of these products in your diet without first talking to your doctor or other healthcare professional. Contact your doctor if your condition changes or you experience increased side effects. Orange juice is not expected to interact.