Drug Interactions between avacopan and finasteride / tadalafil

Tadalafil can lower blood pressure, and combining it with alcohol may further increase this effect. You may be more likely to experience symptoms such as dizziness, lightheadedness, fainting, flushing, headache, and heart palpitations. You should avoid or limit the use of alcohol to not more than 4 alcohol-containing drinks during a small period of time while being treated with tadalafil, and use caution when getting up from a sitting or lying position. You may also want to avoid drinking large amounts of grapefruit juice, since it may increase the blood levels and effects of tadalafil. 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.

To ensure adequate absorption of the medication, avacopan should be taken with food. You should avoid or limit consumption of grapefruit, grapefruit juice, or any supplements that contain grapefruit extract during treatment with avacopan unless directed otherwise by your doctor. Grapefruit juice can increase the blood levels of avacopan. This may increase the risk and/or severity of side effects such as nausea, vomiting, diarrhea, infections, and liver problems. You should seek immediate medical attention if you develop signs and symptoms of liver damage such as fever, chills, joint pain or swelling, unusual bleeding or bruising, skin rash, itching, loss of appetite, fatigue, nausea, vomiting, dark colored urine, light colored stools, and yellowing of the skin or eyes. Talk to your doctor if you have any questions or concerns. 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.