Fenfluramine: uses, dosing, side effects & brands
Fenfluramine is a medicine sold in the U.S. under one brand, for autistic disorder, bulimia and obesity. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
Key facts
- Treats
- Autistic Disorder, Bulimia and Obesity
- Available as
- Solution
- Sold as
- Fintepla
- Prescription?
- Prescription only
- Generic available?
- Not in our catalog
- Boxed warning
- Boxed warning
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How fenfluramine is dosed
From the FDA label for Fintepla (application NDA212102). Other fenfluramine products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
FINTEPLA is to be administered orally and may be taken with or without food. ( 2.2 ) Dravet Syndrome The initial starting and maintenance dosage is 0.1 mg/kg twice daily, which can be increased weekly based on efficacy and tolerability. ( 2.2 ) The maximum daily maintenance dosage of FINTEPLA is 0.35 mg/kg twice daily (maximum daily dosage of 26 mg). ( 2.2 ) Lennox-Gastaut Syndrome The initial starting dosage is 0.1 mg/kg twice daily, which should be increased weekly based on tolerability. ( 2.2 ) The recommended maintenance dosage of FINTEPLA is 0.35 mg/kg twice daily (maximum daily dosage of 26 mg). ( 2.2 ) Dravet Syndrome and Lennox-Gastaut Syndrome Dose adjustment is required in patients taking concomitant stiripentol plus clobazam: the maximum daily maintenance dosage of FINTEPLA is 0.2 mg/kg twice daily (maximum daily dosage of 17 mg). ( 2.2 , 2.3 , 2.4 , 7.1 ) Dosage adjustment is recommended in patients: Taking strong CYP1A2 or CYP2D6 inhibitors ( 2.3 , 7.1 ) With severe renal impairment ( 2.4 , 8.6 ) With mild, moderate, and severe hepatic impairment ( 2.5 , 8.7 ) 2.1 Assessments Prior to Initiating FINTEPLA Prior to starting treatment with FINTEPLA, obtain an echocardiogram assessment to evaluate for valvular heart disease and pulmonary arterial hypertension [see Dosage and Administration (2.6) and Warnings and Precautions (5.1) ] . 2.2 Dosing Information FINTEPLA is…
Fenfluramine side effects
The following clinically significant adverse reactions are described elsewhere in labeling: Valvular Heart Disease and Pulmonary Arterial Hypertension [see Warnings and Precautions (5.1) ] Decreased Appetite and Decreased Weight [see Warnings and Precautions (5.3) ] Somnolence, Sedation, and Lethargy [see Warnings and Precautions (5.4) ] Suicidal Behavior and Ideation [see Warnings and Precautions (5.5) ] Withdrawal of Antiepileptic Drugs [see Warnings and Precautions (5.6) ] Serotonin Syndrome [see Warnings and Precautions (5.7) ] Increase in Blood Pressure [see Warnings and Precautions (5.8) ] Glaucoma [see Warnings and Precautions (5.9) ] The most common adverse reactions (incidence at least 10% and greater than placebo) in patients with Dravet syndrome were decreased appetite; somnolence, sedation, lethargy; diarrhea; constipation; abnormal echocardiogram; fatigue, malaise, asthenia; ataxia, balance disorder, gait disturbance; blood pressure increased; drooling, salivary hypersecretion; pyrexia; upper respiratory tract infection; vomiting; decreased weight; fall; status epilepticus. ( 6.1 ) The most common adverse reactions (incidence at least 10% and greater than placebo) in patients with Lennox-Gastaut syndrome were diarrhea; decreased appetite; fatigue; somnolence; vomiting. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact UCB, Inc. at 1-844-599-2273 or FDA at…
Who shouldn’t take fenfluramine
FINTEPLA is contraindicated in patients with: Hypersensitivity to fenfluramine or any of the excipients in FINTEPLA [see Description (11) ] Concomitant use, or within 14 days of the administration, of monoamine oxidase inhibitors because of an increased risk of serotonin syndrome [see Warnings and Precautions (5.7) ] Hypersensitivity to fenfluramine or any of the excipients in FINTEPLA ( 4 ) Within 14 days of the administration of monoamine oxidase inhibitors due to an increased risk of serotonin syndrome ( 4 )
Fenfluramine drug interactions
Dose adjustment is required for patients taking stiripentol plus clobazam. ( 2.2 , 2.3 , 7.1 ) Strong CYP1A2 or CYP2D6 inhibitors: a dose adjustment is recommended ( 2.3 , 7.1 ) Strong CYP1A2, CYP2B6, or CYP3A4 inducers: it is recommended to avoid coadministration with FINTEPLA. If coadministration is necessary, consider a FINTEPLA dosage increase. ( 7.1 ) 7.1 Effect of Other Drugs on FINTEPLA Stiripentol Plus Clobazam Coadministration of FINTEPLA with stiripentol plus clobazam, with or without valproate, increases fenfluramine plasma concentrations [see Clinical Pharmacology (12.3) ]. If FINTEPLA is coadministered with stiripentol plus clobazam, the maximum daily dosage of FINTEPLA is 0.2 mg/kg twice daily (maximum daily dosage of 17 mg) [see Dosage and Administration (2.2) ] . Strong CYP1A2, CYP2B6, or CYP3A Inducers Coadministration of FINTEPLA with strong CYP1A2, CYP2B6, or CYP3A inducers will decrease fenfluramine plasma concentrations, which may lower the efficacy of FINTEPLA [see Clinical Pharmacology (12.3) ] . It is recommended to avoid coadministration of strong CYP1A2, CYP2B6 or CYP3A inducers. If coadministration of a strong CYP1A2, CYP2B6, or CYP3A inducer with FINTEPLA is necessary, monitor the patient for reduced efficacy and consider increasing the dosage of FINTEPLA as needed; however, do not exceed the maximum daily dosage of FINTEPLA [see Dosage and Administration (2.2) ]. If a strong CYP1A2, CYP2B6, or CYP3A inducer is discontinued during maintenance treatment with FINTEPLA, consider gradual reduction in the FINTEPLA dosage to the dose administered prior to initiating the inducer [see Warnings and Precautions (5.6) ]. Strong CYP1A2 or CYP2D6 Inhibitors Coadministration of FINTEPLA with strong CYP1A2 or CYP2D6 inhibitors will increase fenfluramine plasma concentrations [see Clinical Pharmacology (12.3) ] . If FINTEPLA is coadministered with strong CYP1A2 or CYP2D6 inhibitors, the maximum daily dosage of FINTEPLA is 20 mg [see Dosage and Administration (2.3) ]. If a strong CYP1A2 or CYP2D6 inhibitor is discontinued during maintenance treatment with FINTEPLA, consider gradual increase in the FINTEPLA dosage to the dose recommended without CYP1A2 or CYP2D6 inhibitors; however, do not exceed the maximum daily dosage of FINTEPLA [see Dosage and Administration (2.2) ]. If FINTEPLA is coadministered with stiripentol and a strong CYP1A2 or CYP2D6 inhibitor, do not exceed the maximum daily dosage of FINTEPLA of 17 mg [see Dosage and Administration (2.3) ]. 7.2 Effects of Serotonin Receptor Antagonists Cyproheptadine and potent 5-HT1A, 5-HT1D, 5-HT2A, and 5-HT2C serotonin receptor antagonists may decrease the efficacy of FINTEPLA. If cyproheptadine or potent 5--HT1A, 5--HT1D, 5-HT2A, or 5-HT2C serotonin receptor antagonists are coadministered with FINTEPLA, patients should be monitored appropriately. 7.3 Serotonergic Drugs Concomitant administration of FINTEPLA and drugs (e.g., SSRIs, SNRIs, TCAs, MAO inhibitors, trazodone, etc.), over-the-counter medications (e.g., dextromethorphan), or herbal supplements (e.g., St. John's Wort) that increase serotonin may increase the risk of serotonin syndrome [see Warnings and Precautions (5.7) ]. Concomitant use of FINTEPLA is contraindicated within 14 days of taking MAOIs. Use FINTEPLA with caution in patients taking other medications that increase serotonin.
Every fenfluramine product we track (1)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
Only one: Fintepla.
What people report to the FDA about fenfluramine
The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 830 reports naming fenfluramine, and the FDA flagged 88% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:
- seizure189 reports
- tricuspid valve incompetence119 reports
- prescribed underdose117 reports
- epilepsy111 reports
- decreased appetite109 reports
- somnolence84 reports
- generalised tonic-clonic seizure64 reports
- diarrhoea62 reports
Read these as a signal, not a rate. A report does not mean fenfluramine caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label section above.
Source: openFDA drug/event (FAERS), retrieved July 25, 2026.
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Frequently asked questions
What is fenfluramine?
Fintepla (Fenfluramine Hydrochloride) is a medication used to treat Autistic Disorder, Bulimia, Obesity.
Can you take fenfluramine with other medicines?
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run fenfluramine against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What forms does fenfluramine come in?
Across the brands we track, fenfluramine is currently marketed as solution, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Is there a generic fenfluramine?
We do not currently list a generic-labelled fenfluramine product. That does not always mean none exists — it means none appears under a generic name in the FDA data we track. Ask your pharmacist.
Cite this page
- APA
- pharmaranks. (2026, July 24). Fenfluramine: uses, dosing, side effects & brands. https://pharmaranks.com/drugs/fenfluramine
- MLA
- “Fenfluramine: uses, dosing, side effects & brands.” pharmaranks, 24 July 2026, https://pharmaranks.com/drugs/fenfluramine.
We summarise public FDA and NIH sources — for a clinical claim, cite the primary source we link to as well.
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Read the full FDA label for fenfluramine on DailyMed (NIH) ↗ — including its boxed warning in full.