Drug Interaction Report

Consumer information for this interaction is not currently available.

MONITOR: Coadministration with fenfluramine may decrease the plasma concentrations and therapeutic efficacy of drugs that are substrates of the CYP450 2B6 and/or CPY3A4 isoenzymes. The proposed mechanism, based on in vitro data, might be increased clearance due to induction of CYP450 2B6 and intestinal CYP450 3A4.

MANAGEMENT: Caution and monitoring are recommended if fenfluramine is used concomitantly with drugs that are substrates of CYP450 2B6 and/or CYP450 3A4, particularly sensitive substrates or those with a narrow therapeutic range. Monitoring for potential loss of therapeutic efficacy is recommended. The prescribing information for concomitant medications may be consulted to assess the benefits versus risks of coadministration, as well as any dosage adjustments that may be required during coadministration and/or following the discontinuation of a CYP450 2B6 and/or CYP450 3A4 inducer.

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.

Ask your doctor before using doxazosin together with ethanol (alcohol). Using doxazosin with ethanol (alcohol) can lower your blood pressure. This can cause dizziness or feeling like you might pass out, especially when getting up from a sitting or lying position. This may be more likely to occur when you first start taking either of these medications. You may need a dose adjustment or need your blood pressure checked more often if you take both medications. You may develop flushing, warmth or redness under your skin or tingly feeling after alcohol intake (especially in you are of Asian descent) and should be advised to avoid alcohol or limit your intake. 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.