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.

Grapefruit and grapefruit juice can increase the levels of cycloSPORINE in your body and should generally not be consumed during treatment. High blood levels of cycloSPORINE can lead to increased risk of serious side effects on kidney, liver, and nervous system functions. If you regularly consume grapefruits or grapefruit juice, you should be monitored for side effects and/or changes in cycloSPORINE levels. However, do not increase or decrease the amount of grapefruit products in your diet without first talking to your doctor. You should also take cycloSPORINE on a consistent schedule with regard to time of day and relation to meals. Let your doctor know if you experience fever, rash, nausea, vomiting, abdominal pain, loss of appetite, dark urine, jaundice (yellowing of the skin or eyes), decreased urination, excessive thirst, swelling, weight gain, dizziness, fatigue, weakness, headache, blurred vision, numbness/burning/tingling in the hand and feet, tremors, or convulsions, as they may be symptoms caused by excessive effects of cycloSPORINE.

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.