Drug Interaction Report

Fenfluramine may increase the blood levels and effects of tamsulosin. This can cause blood pressure to fall excessively and heart rate to increase, especially when you rise from a sitting or lying position. The risk of other side effects such as dizziness, lightheadedness, fainting, headache, flushing, nasal congestion, heart palpitations, and priapism (prolonged and painful erection unrelated to sexual activity) may also increase. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. Let your doctor know if you develop these symptoms while using tamsulosin and they do not go away on their own or they become troublesome. Avoid driving or operating hazardous machinery until you know how the medication affects you, and use caution when getting up from a sitting or lying position. 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.

Using fenfluramine with alcohol can increase the risk of cardiovascular side effects such as increased heart rate, chest pain, or blood pressure changes. In addition, you may also be more likely to experience nervous system side effects such as dizziness, drowsiness, depression, and difficulty concentrating. You should avoid or limit the use of alcohol while being treated with fenfluramine. Do not use more than the recommended dose of fenfluramine, and 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 medication without first talking to your doctor.

Food may affect the intestinal absorption of tamsulosin. You should take tamsulosin approximately one-half hour following the same meal each day to ensure steady absorption and blood levels of the drug.