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Fenfluramine Dosage

Medically reviewed by Drugs.com. Last updated on Aug 4, 2020.

Applies to the following strengths: 20 mg; 2.2 mg/mL

Usual Adult Dose for:

Usual Pediatric Dose for:

Additional dosage information:

Usual Adult Dose for Seizures

Initial dose: 0.1 mg/kg orally 2 times a day
-May increase dose weekly for further reduction of seizures; dose increases are based on concomitant therapy, efficacy, and tolerability:

For Patients NOT on Concomitant Stiripentol:
-On Day 7: May increase to 0.2 mg/kg orally 2 times a day
-On Day 14: May increase to 0.35 mg/kg orally 2 times a day
Maximum Dose: 26 mg/day

For Patients on Concomitant Stiripentol and Clobazam:
-On Day 7: May increase to 0.15 mg/kg orally 2 times a day
-On Day 14: May increase to 0.2 mg/kg orally 2 times a day
Maximum Dose: 17 mg/day

Comments:
-For patients not on concomitant stiripentol and for whom a more rapid titration is warranted, the dose may be increased every 4 days.

Use: For the treatment of seizures associated with Dravet syndrome.

Usual Pediatric Dose for Seizures

Age: 2 years and older:
Initial dose: 0.1 mg/kg orally 2 times a day
-May increase dose weekly for further reduction of seizures; dose increases are based on concomitant therapy, efficacy, and tolerability:

For Patients NOT on Concomitant Stiripentol:
-On Day 7: May increase to 0.2 mg/kg orally 2 times a day
-On Day 14: May increase to 0.35 mg/kg orally 2 times a day
Maximum Dose: 26 mg/day

For Patients on Concomitant Stiripentol and Clobazam:
-On Day 7: May increase to 0.15 mg/kg orally 2 times a day
-On Day 14: May increase to 0.2 mg/kg orally 2 times a day
Maximum Dose: 17 mg/day

Comments:
-For patients not on concomitant stiripentol and for whom a more rapid titration is warranted, the dose may be increased every 4 days.

Use: For the treatment of seizures associated with Dravet syndrome in patients 2 years and older.

Renal Dose Adjustments

Mild renal dysfunction: No adjustment recommended.
Moderate to severe renal dysfunction: Not recommended.

Liver Dose Adjustments

Not recommended.

Dose Adjustments

Elderly: Clinical studies did not include patients 65 years of age and over. Dose selection for an elderly patient should be cautious, starting at the low end of the dosing range.

Withdrawal of Antiepileptic Drugs (AEDs):
-This drug should normally be gradually withdrawn to reduce the potential for increased seizure frequency and status epilepticus

Precautions

The US FDA requires a Risk Evaluation and Mitigation Strategy (REMS) for this drug. It includes a communication plan, elements to assure safe use, and an implementation system. For additional information go to: www.accessdata.fda.gov/scripts/cder/rems/index.cfm

US BOXED WARNINGS:
-There is an association between serotonergic drugs with 5-HT2B receptor agonist activity; including fenfluramine, and valvular heart disease and pulmonary arterial hypertension.
-Echocardiogram assessments are required before, during, and after treatment; the benefits versus the risks of initiating or continuing therapy must be considered, based on echocardiogram findings.
-Because of the risks of valvular heart disease and pulmonary arterial hypertension, this drug is available only through a restricted program under a REMS called the FINTEPLA REMS

CONTRAINDICATIONS:
-Hypersensitivity to any of the ingredients
-Within 14 days of the administration of monoamine oxidase inhibitors due to an increased risk of serotonin syndrome

Safety and efficacy have not been established in patients younger than 2 years.

Consult WARNINGS section for additional precautions.

US Controlled Substance: Schedule IV

Dialysis

Data not available

Other Comments

Administration advice:
-Administer orally with or without food using a calibrated measuring device; a household teaspoon or tablespoon is not an adequate measuring device
-This drug is compatible with commercially available gastric and nasogastric feeding tubes

Storage requirements:
-Store at room temperature between 20 and 25C (68 to 77F); do not refrigerate or freeze
-Discard any unused portion 3 months after first opening or the "discard after" date, whichever is sooner

Preparation:
-Before dispensing, insert a press-in bottle adapter into the dispensed bottle
-Provide a 3 mL or 6 mL calibrated oral dosing syringe

General:
-This drug in tablet form was previously approved for the treatment of obesity, but was removed from the market for causing adverse cardiac events.

Monitoring:
-Prior to starting treatment, obtain an echocardiogram assessment to evaluate for valvular heart disease and pulmonary arterial hypertension; repeat every 6 months during treatment, and once more, 3 to 6 months after final dose
-Monitor blood pressure
-Monitor height and weight in pediatric patients
-Monitor for somnolence, sedation, and lethargy
-Monitor for emergence or worsening of depression and/or any unusual changes in mood or behavior

Patient advice:
-Patients/caregivers should be instructed to read the Medication Guide and Instructions for Use.
-This drug can cause somnolence, sedation, and lethargy. Be cautious about operating machinery and driving until you know how it will affect you.
-Contact immediately your health care provider if you have new or worsening symptoms of depression, unusual changes in mood or behavior, or new suicidal thoughts, behavior, or thoughts of self-harm.
-Do not discontinue this drug without consulting your health care provider. Withdrawal should be gradual to reduce the risk of seizures.
-Contact your healthcare provider if you have changes in your vision or ocular pain.
-Female patients: Notify your health care provider if you become pregnant while taking this drug or intend to become pregnant. You will need to enroll in a pregnancy registry assessing the safety of this drug during pregnancy.

Frequently asked questions

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.