Drug Interaction Report

Talk to your doctor before using macitentan together with hydroxychloroquine. Hydroxychloroquine may increase the blood levels of macitentan. In some cases, this may increase the risk and/or severity of side effects such as headache, anemia and liver problems, especially during prolonged treatment. Your doctor may be able to prescribe alternatives that do not interact. Call your doctor immediately if you have fever, chills, joint pain or swelling, unusual bleeding or bruising, skin rash, itching, loss of appetite, fatigue, nausea, vomiting, abdominal pain, dark colored urine, light colored stools, and/or yellowing of the skin or eyes, as these may be signs and symptoms of liver damage. 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 hydroxychloroquine. Grapefruit juice can significantly increase the blood levels and effects of hydroxychloroquine, 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 hydroxychloroquine. 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.