Drug Interactions between allopurinol and st. john's wort

Allopurinol should generally be taken after a meal to reduce side effects. If your daily dose exceeds 300 mg, you may also ask your healthcare provider if it is okay to divide the total daily dose into smaller doses given more frequently instead of once a day, as this may also reduce stomach upset that can happen with allopurinol. It is best to avoid or limit the consumption of alcohol, as it can increase drowsiness or other nervous system side effects of allopurinol. You should also avoid activities requiring mental alertness such as 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.

While you are taking St. John's wort, you must not eat or drink certain foods and beverages that are high in tyramine. Eating these foods while you are taking St. John's wort can raise your blood pressure to dangerous levels. This may cause life threatening symptoms such as sudden and severe headache, confusion, blurred vision, problems with speech or balance, nausea, vomiting, chest pain, seizure (convulsions), and sudden numbness or weakness (especially on one side of the body). Call your doctor at once if you have any of these symptoms. Foods that are high in tyramine include: air dried meats, aged or fermented meats, sausage or salami, pickled herring, and any spoiled or improperly stored beef, poultry, fish, or liver, red wine, beer from a tap, beer that has not been pasteurize, aged cheeses, including blue, brick, brie, cheddar, parmesan, romano, and swiss, sauerkraut, over the counter supplements or cough and cold medicines that contain tyramine, soy beans, soy sauce, tofu, miso soup, bean curd, fava beans, or yeast extracts (such as Marmite). Caffeine intake should be limited as well. You should avoid or limit the use of alcohol while being treated with St. John's wort. Alcohol can increase the nervous system side effects of St. John's wort such as dizziness, drowsiness, and difficulty concentrating. Some people may also experience impairment in thinking and judgment. Talk to your doctor or pharmacist if you have any questions or concerns.