Dosing & Uses
Dosage Forms & Strengths
oral solution, Schedule IV
- 2.2mg/mL
Seizures
Indicated for treatment of seizures associated with Dravet syndrome or Lennox-Gastaut syndrome
Without concomitant stiripentol
- Initial dose: 0.1 mg/kg PO BID; not to exceed 26 mg/day
- May be increased weekly based on efficacy and tolerability
- On Day 7: May increase dose up to 0.2 mg/kg PO BID (maximum of 26 mg/day)
- On Day 14: May increase dose up to 0.35 mg/kg PO BID (maximum of 26 mg/day)
- Patients who require rapid titration may increase dose every 4 days
With concomitant stiripentol and clobazam
- Initial dose: 0.1 mg/kg PO BID; not to exceed 17 mg/day
- May be increased weekly based on efficacy and tolerability
- On Day 7: May increase dose up to 0.15 mg/kg PO BID (maximum of 17 mg/day)
- On Day 14: May increase dose up to 0.2 mg/kg PO BID (maximum of 17 mg/day)
Dosage Modifications
Coadministration with strong CYP1A2 or CYP2D6 inhibitors
- Without concomitant stiripentol: Not to exceed 20 mg/day
- With concomitant stiripentol plus clobazam: Not to exceed 17 mg/day
Renal impairment
- Mild-to-moderate (eGFR ≥30 mL/min/1.73m2): No adjustment recommended
- Severe (eGFR <15 mL/min/1.73m2): Not studied
- Hemodialysis: Unknown if fenfluramine or norfenfluramine are dialyzable
-
eGFR 15-29 mL/min/1.73m2
- Without concomitant stiripentol: Not to exceed 20 mg/day
- With concomitant stiripentol plus clobazam: Not to exceed 17 mg/day
Hepatic impairment
-
Without concomitant stiripentol
- Mild-to-moderate(Child-Pugh A or B): Not to exceed 20 mg/day
- Severe (Child-Pugh C): Not to exceed 17 mg/day
-
With concomitant stiripentol and clobazam
- Mild (Child-Pugh A): Not to exceed 13 mg/day
- Moderate-to-severe (Child-Pugh B or C): Use not recommended
Dosing Considerations
Echocardiogram (ECHO)
- Evaluate for valvular heart disease (VHD) and pulmonary arterial hypertension (PAH)
- Obtain ECHO every 6 months during treatment, and 3-6 months after final dose
Discontinuing fenfluramine
- Gradually decrease dose
- Avoid abrupt discontinuation when possible, to minimize the risk of increased seizure frequency and status epilepticus
Dosage Forms & Strengths
oral solution, Schedule IV
- 2.2mg/mL
Seizures
Indicated for treatment of seizures associated with Dravet syndrome or Lennox-Gastaut syndrome in patients aged ≥2 years
-
Without concomitant stiripentol
- Initial dose: 0.1 mg/kg PO BID; not to exceed 26 mg/day
- May be increased weekly based on efficacy and tolerability
- On Day 7: May increase dose up to 0.2 mg/kg PO BID (maximum of 26 mg/day)
- On Day 14: May increase dose up to 0.35 mg/kg PO BID (maximum of 26 mg/day)
- Patients who require rapid titration may increase dose every 4 days
-
With concomitant stiripentol and clobazam
- Initial dose: 0.1 mg/kg PO BID; not to exceed 17 mg/day
- May be increased weekly based on efficacy and tolerability
- On Day 7: May increase dose up to 0.15 mg/kg PO BID (maximum of 17 mg/day)
- On Day 14: May increase dose up to 0.2 mg/kg PO BID (maximum of 17 mg/day)
Dosage Modifications
Coadministration with strong CYP1A2 or CYP2D6 inhibitors
- Without concomitant stiripentol: Not to exceed 20 mg/day
- With concomitant stiripentol plus clobazam: Not to exceed 17 mg/day
Renal impairment
- Mild-to-moderate (eGFR ≥30 mL/min/1.73m2): No adjustment recommended
- Severe (eGFR <15 mL/min/1.73m2): Not studied
- Hemodialysis: Unknown if fenfluramine or norfenfluramine are dialyzable
-
eGFR 15-29 mL/min/1.73m2
- Without concomitant stiripentol: Not to exceed 20 mg/day
- With concomitant stiripentol plus clobazam: Not to exceed 17 mg/day
Hepatic impairment
-
Without concomitant stiripentol
- Mild-to-moderate(Child-Pugh A or B): Not to exceed 20 mg/day
- Severe (Child-Pugh C): Not to exceed 17 mg/day
-
With concomitant stiripentol and clobazam
- Mild (Child-Pugh A): Not to exceed 13 mg/day
- Moderate-to-severe (Child-Pugh B or C): Use not recommended
Dosing Considerations
Echocardiogram (ECHO)
- Evaluate for valvular heart disease (VHD) and pulmonary arterial hypertension (PAH)
- Obtain ECHO every 6 months during treatment, and 3-6 months after final dose
Monitor growth
- Carefully monitor growth of children and adolescents
- Monitor weight regularly during treatment; consider dose modifications if decreased weight observed
Discontinuing fenfluramine
- Gradually decrease dose
- Avoid abrupt discontinuation when possible, to minimize the risk of increased seizure frequency and status epilepticus
Interactions
Interaction Checker
No Results
Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor
Contraindicated (5)
- isocarboxazid
isocarboxazid increases effects of fenfluramine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.
fenfluramine, isocarboxazid. Either increases effects of the other by serotonin levels. Contraindicated. Coadministration with drugs that increase serotonin may increase the risk of serotonin syndrome. Do not use concomitantly or within 14 days of MAOIs. - linezolid
linezolid increases effects of fenfluramine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.
- phenelzine
phenelzine increases effects of fenfluramine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.
fenfluramine, phenelzine. Either increases effects of the other by serotonin levels. Contraindicated. Coadministration with drugs that increase serotonin may increase the risk of serotonin syndrome. Do not use concomitantly or within 14 days of MAOIs. - selegiline transdermal
selegiline transdermal increases effects of fenfluramine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.
- tranylcypromine
tranylcypromine increases effects of fenfluramine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.
fenfluramine, tranylcypromine. Either increases effects of the other by serotonin levels. Contraindicated. Coadministration with drugs that increase serotonin may increase the risk of serotonin syndrome. Do not use concomitantly or within 14 days of MAOIs.
Serious - Use Alternative (30)
- amitriptyline
amitriptyline, fenfluramine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.
- amoxapine
amoxapine, fenfluramine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.
- cabergoline
fenfluramine, cabergoline. Either increases toxicity of the other by pharmacodynamic synergism. Contraindicated. Risk of serotonin syndrome.
cabergoline, fenfluramine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension. - clomipramine
clomipramine, fenfluramine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.
- desflurane
desflurane increases toxicity of fenfluramine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.
- desipramine
desipramine, fenfluramine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.
- dihydroergotamine
fenfluramine, dihydroergotamine. Either increases toxicity of the other by pharmacodynamic synergism. Contraindicated. Risk of serotonin syndrome.
dihydroergotamine, fenfluramine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension. - dihydroergotamine intranasal
dihydroergotamine intranasal, fenfluramine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.
fenfluramine, dihydroergotamine intranasal. Either increases toxicity of the other by pharmacodynamic synergism. Contraindicated. Risk of serotonin syndrome. - doxapram
doxapram increases effects of fenfluramine by pharmacodynamic synergism. Avoid or Use Alternate Drug. Additive pressor effect.
- doxepin
doxepin, fenfluramine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.
- ergoloid mesylates
fenfluramine, ergoloid mesylates. Either increases toxicity of the other by pharmacodynamic synergism. Contraindicated. Risk of serotonin syndrome.
ergoloid mesylates, fenfluramine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension. - ergotamine
fenfluramine, ergotamine. Either increases toxicity of the other by pharmacodynamic synergism. Contraindicated. Risk of serotonin syndrome.
ergotamine, fenfluramine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension. - ether
ether increases toxicity of fenfluramine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.
- imipramine
imipramine, fenfluramine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.
- isocarboxazid
isocarboxazid and fenfluramine both increase serotonin levels. Avoid or Use Alternate Drug.
- isoflurane
isoflurane increases toxicity of fenfluramine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.
- linezolid
linezolid and fenfluramine both increase serotonin levels. Avoid or Use Alternate Drug. Linezolid may increase serotonin as a result of MAO-A inhibition. If linezolid must be administered, discontinue serotonergic drug immediately and monitor for CNS toxicity. Serotonergic therapy may be resumed 24 hours after last linezolid dose or after 2 weeks of monitoring, whichever comes first.
- lofepramine
lofepramine, fenfluramine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.
- maprotiline
maprotiline, fenfluramine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.
- methoxyflurane
methoxyflurane increases toxicity of fenfluramine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.
- methylergonovine
fenfluramine, methylergonovine. Either increases toxicity of the other by pharmacodynamic synergism. Contraindicated. Risk of serotonin syndrome.
methylergonovine, fenfluramine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension. - nortriptyline
nortriptyline, fenfluramine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.
- olopatadine intranasal
fenfluramine and olopatadine intranasal both increase sedation. Avoid or Use Alternate Drug. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.
- phenelzine
phenelzine and fenfluramine both increase serotonin levels. Avoid or Use Alternate Drug.
- protriptyline
protriptyline, fenfluramine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.
- sevoflurane
sevoflurane increases toxicity of fenfluramine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.
- tranylcypromine
tranylcypromine and fenfluramine both increase serotonin levels. Avoid or Use Alternate Drug.
- trazodone
trazodone, fenfluramine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.
- trimipramine
trimipramine, fenfluramine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.
- yohimbe
yohimbe, fenfluramine. Mechanism: pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.
Monitor Closely (242)
- 5-HTP
5-HTP and fenfluramine both increase serotonin levels. Use Caution/Monitor.
- acrivastine
acrivastine and fenfluramine both increase sedation. Use Caution/Monitor.
- albuterol
albuterol and fenfluramine both decrease sedation. Use Caution/Monitor.
albuterol and fenfluramine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - alfentanil
alfentanil increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- almotriptan
almotriptan and fenfluramine both increase serotonin levels. Use Caution/Monitor.
fenfluramine, almotriptan. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - alosetron
alosetron decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately.
- alprazolam
alprazolam increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- amitriptyline
amitriptyline increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
amitriptyline and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
fenfluramine, amitriptyline. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - amobarbital
amobarbital increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- amoxapine
amoxapine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
amoxapine and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
fenfluramine, amoxapine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - arformoterol
arformoterol and fenfluramine both decrease sedation. Use Caution/Monitor.
arformoterol and fenfluramine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - aripiprazole
aripiprazole increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
aripiprazole decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately. - armodafinil
armodafinil and fenfluramine both decrease sedation. Use Caution/Monitor.
- asenapine
asenapine decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately.
asenapine and fenfluramine both increase sedation. Use Caution/Monitor. - asenapine transdermal
asenapine transdermal decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately.
asenapine transdermal and fenfluramine both increase sedation. Use Caution/Monitor. - azelastine
azelastine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- baclofen
baclofen increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- belladonna and opium
belladonna and opium increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- benperidol
benperidol increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- benzphetamine
benzphetamine and fenfluramine both decrease sedation. Use Caution/Monitor.
benzphetamine and fenfluramine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - brexanolone
fenfluramine, brexanolone. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome.
- brompheniramine
brompheniramine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- buprenorphine
buprenorphine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- buprenorphine buccal
buprenorphine buccal increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- bupropion
fenfluramine, bupropion. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome.
- buspirone
buspirone and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
- butabarbital
butabarbital increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- butalbital
butalbital increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- butorphanol
butorphanol increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- caffeine
caffeine and fenfluramine both decrease sedation. Use Caution/Monitor.
- carbinoxamine
carbinoxamine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- cariprazine
cariprazine decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately.
- carisoprodol
carisoprodol increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- chloral hydrate
chloral hydrate increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- chlordiazepoxide
chlordiazepoxide increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- chlorpheniramine
chlorpheniramine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- chlorpromazine
chlorpromazine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
chlorpromazine, fenfluramine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only. - chlorzoxazone
chlorzoxazone increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- cinnarizine
cinnarizine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- citalopram
fenfluramine, citalopram. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome.
- clemastine
clemastine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- clomipramine
clomipramine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
clomipramine and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
fenfluramine, clomipramine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - clonazepam
clonazepam increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- clorazepate
clorazepate increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- clozapine
clozapine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
clozapine decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately. - cocaine topical
cocaine topical and fenfluramine both increase serotonin levels. Use Caution/Monitor.
- codeine
codeine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- cyclizine
cyclizine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- cyclobenzaprine
cyclobenzaprine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- cyproheptadine
cyproheptadine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
cyproheptadine decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately. - dantrolene
dantrolene increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- daridorexant
fenfluramine and daridorexant both increase sedation. Modify Therapy/Monitor Closely. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.
- desflurane
desflurane increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- desipramine
desipramine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
desipramine and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
fenfluramine, desipramine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - desvenlafaxine
fenfluramine, desvenlafaxine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome.
- dexchlorpheniramine
dexchlorpheniramine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- dexfenfluramine
dexfenfluramine and fenfluramine both decrease sedation. Use Caution/Monitor.
dexfenfluramine and fenfluramine both increase serotonin levels. Use Caution/Monitor.
dexfenfluramine and fenfluramine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - dexmedetomidine
dexmedetomidine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- dexmethylphenidate
dexmethylphenidate and fenfluramine both decrease sedation. Use Caution/Monitor.
dexmethylphenidate and fenfluramine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - dextroamphetamine
dextroamphetamine and fenfluramine both decrease sedation. Use Caution/Monitor.
dextroamphetamine and fenfluramine both increase serotonin levels. Use Caution/Monitor.
dextroamphetamine and fenfluramine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - dextromethorphan
dextromethorphan and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
fenfluramine, dextromethorphan. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - dextromoramide
dextromoramide increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- diamorphine
diamorphine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- diazepam
diazepam increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- diethylpropion
diethylpropion and fenfluramine both decrease sedation. Use Caution/Monitor.
diethylpropion and fenfluramine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - difelikefalin
difelikefalin and fenfluramine both increase sedation. Use Caution/Monitor.
- difenoxin hcl
difenoxin hcl increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- dihydroergotamine
dihydroergotamine and fenfluramine both increase serotonin levels. Use Caution/Monitor.
dihydroergotamine decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately. - dihydroergotamine inhaled
dihydroergotamine inhaled decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately.
- dihydroergotamine intranasal
dihydroergotamine intranasal and fenfluramine both increase serotonin levels. Use Caution/Monitor.
dihydroergotamine intranasal decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately. - dimenhydrinate
dimenhydrinate increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- diphenhydramine
diphenhydramine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- diphenoxylate hcl
diphenoxylate hcl increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- dipipanone
dipipanone increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- dobutamine
dobutamine and fenfluramine both decrease sedation. Use Caution/Monitor.
dobutamine and fenfluramine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - dolasetron
dolasetron decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately.
- dopamine
dopamine and fenfluramine both decrease sedation. Use Caution/Monitor.
dopamine and fenfluramine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - dopexamine
dopexamine and fenfluramine both decrease sedation. Use Caution/Monitor.
dopexamine and fenfluramine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - doxepin
doxepin increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxepin and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
fenfluramine, doxepin. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - doxylamine
doxylamine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- droperidol
droperidol increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- duloxetine
duloxetine and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
fenfluramine, duloxetine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - eletriptan
eletriptan and fenfluramine both increase serotonin levels. Use Caution/Monitor.
fenfluramine, eletriptan. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - ephedrine
ephedrine and fenfluramine both decrease sedation. Use Caution/Monitor.
ephedrine and fenfluramine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.
ephedrine, fenfluramine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. - epinephrine
epinephrine and fenfluramine both decrease sedation. Use Caution/Monitor.
epinephrine and fenfluramine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - epinephrine racemic
epinephrine racemic and fenfluramine both decrease sedation. Use Caution/Monitor.
epinephrine racemic and fenfluramine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - ergoloid mesylates
ergoloid mesylates decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately.
- ergonovine
ergonovine decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately.
- ergotamine
ergotamine and fenfluramine both increase serotonin levels. Use Caution/Monitor.
ergotamine decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately. - escitalopram
escitalopram and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
fenfluramine, escitalopram. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - esketamine intranasal
fenfluramine, esketamine intranasal. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome.
- estazolam
estazolam increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- ethanol
ethanol increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- etomidate
etomidate increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- flibanserin
fenfluramine, flibanserin. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome.
- fluoxetine
fluoxetine and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
fenfluramine, fluoxetine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - fluphenazine
fluphenazine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
fluphenazine, fenfluramine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only. - flurazepam
flurazepam increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- fluvoxamine
fluvoxamine and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
fenfluramine, fluvoxamine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - formoterol
formoterol and fenfluramine both decrease sedation. Use Caution/Monitor.
formoterol and fenfluramine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - frovatriptan
frovatriptan and fenfluramine both increase serotonin levels. Use Caution/Monitor.
fenfluramine, frovatriptan. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - gepirone
fenfluramine, gepirone. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome.
- granisetron
granisetron decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately.
- haloperidol
haloperidol increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- hydralazine
hydralazine, fenfluramine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of hypertension.
- hydromorphone
hydromorphone increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- hydroxyzine
hydroxyzine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- iloperidone
iloperidone increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
iloperidone decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately. - imipramine
imipramine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
imipramine and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
fenfluramine, imipramine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - insulin aspart
fenfluramine increases effects of insulin aspart by Other (see comment). Use Caution/Monitor. Comment: Fenfluramine enhances glucose uptake in peripheral tissue, increasing risk of hypoglycemia.
- insulin detemir
fenfluramine increases effects of insulin detemir by Other (see comment). Use Caution/Monitor. Comment: Fenfluramine enhances glucose uptake in peripheral tissue, increasing risk of hypoglycemia.
- insulin glargine
fenfluramine increases effects of insulin glargine by Other (see comment). Use Caution/Monitor. Comment: Fenfluramine enhances glucose uptake in peripheral tissue, increasing risk of hypoglycemia.
- insulin glulisine
fenfluramine increases effects of insulin glulisine by Other (see comment). Use Caution/Monitor. Comment: Fenfluramine enhances glucose uptake in peripheral tissue, increasing risk of hypoglycemia.
- insulin lispro
fenfluramine increases effects of insulin lispro by Other (see comment). Use Caution/Monitor. Comment: Fenfluramine enhances glucose uptake in peripheral tissue, increasing risk of hypoglycemia.
- insulin NPH
fenfluramine increases effects of insulin NPH by Other (see comment). Use Caution/Monitor. Comment: Fenfluramine enhances glucose uptake in peripheral tissue, increasing risk of hypoglycemia.
- insulin regular human
fenfluramine increases effects of insulin regular human by Other (see comment). Use Caution/Monitor. Comment: Fenfluramine enhances glucose uptake in peripheral tissue, increasing risk of hypoglycemia.
- isoniazid
fenfluramine and isoniazid both increase serotonin levels. Use Caution/Monitor.
- isoproterenol
isoproterenol and fenfluramine both decrease sedation. Use Caution/Monitor.
isoproterenol and fenfluramine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - ketamine
ketamine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- ketotifen, ophthalmic
ketotifen, ophthalmic increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- L-tryptophan
fenfluramine and L-tryptophan both increase serotonin levels. Use Caution/Monitor.
- lasmiditan
fenfluramine, lasmiditan. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome.
- levalbuterol
levalbuterol and fenfluramine both decrease sedation. Use Caution/Monitor.
levalbuterol and fenfluramine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - levomilnacipran
levomilnacipran and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
fenfluramine, levomilnacipran. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - levorphanol
levorphanol increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- lisdexamfetamine
lisdexamfetamine and fenfluramine both decrease sedation. Use Caution/Monitor.
fenfluramine and lisdexamfetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - lithium
fenfluramine and lithium both increase serotonin levels. Use Caution/Monitor.
- lofepramine
lofepramine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
lofepramine and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely. - lofexidine
lofexidine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- loprazolam
loprazolam increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- lorazepam
lorazepam increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- lormetazepam
lormetazepam increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- loxapine
loxapine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- loxapine inhaled
loxapine inhaled increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- lsd
fenfluramine and lsd both increase serotonin levels. Use Caution/Monitor.
- lurasidone
lurasidone decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately.
- maprotiline
maprotiline increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
maprotiline and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
fenfluramine, maprotiline. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - marijuana
marijuana increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- melatonin
melatonin increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- meperidine
meperidine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
fenfluramine and meperidine both increase serotonin levels. Modify Therapy/Monitor Closely. - meprobamate
meprobamate increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- metaproterenol
metaproterenol and fenfluramine both decrease sedation. Use Caution/Monitor.
metaproterenol and fenfluramine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - metaxalone
metaxalone increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- methadone
methadone increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- methamphetamine
methamphetamine and fenfluramine both decrease sedation. Use Caution/Monitor.
fenfluramine and methamphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - methocarbamol
methocarbamol increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- methyldopa
methyldopa increases effects of fenfluramine by unknown mechanism. Use Caution/Monitor.
- methylenedioxymethamphetamine
methylenedioxymethamphetamine and fenfluramine both decrease sedation. Use Caution/Monitor.
fenfluramine and methylenedioxymethamphetamine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - methylergonovine
methylergonovine decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately.
- methylphenidate
fenfluramine and methylphenidate both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.
- methylphenidate transdermal
methylphenidate transdermal will increase the level or effect of fenfluramine by decreasing metabolism. Modify Therapy/Monitor Closely. Consider decreasing the dose of these drugs when given coadministered with methylphenidate. Monitor for drug toxiticities when initiating or discontinuing methylphenidate.
- midazolam
midazolam increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- midodrine
fenfluramine and midodrine both decrease sedation. Use Caution/Monitor.
fenfluramine and midodrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - milnacipran
milnacipran and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
fenfluramine, milnacipran. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - mirtazapine
mirtazapine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
fenfluramine, mirtazapine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - modafinil
modafinil and fenfluramine both decrease sedation. Use Caution/Monitor.
- morphine
morphine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
fenfluramine and morphine both increase serotonin levels. Use Caution/Monitor. - motherwort
motherwort increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- moxonidine
moxonidine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- nabilone
nabilone increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- nalbuphine
nalbuphine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- naratriptan
naratriptan and fenfluramine both increase serotonin levels. Use Caution/Monitor.
fenfluramine, naratriptan. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - nefazodone
nefazodone and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
fenfluramine, nefazodone. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - netupitant/palonosetron
netupitant/palonosetron decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately.
- norepinephrine
norepinephrine and fenfluramine both decrease sedation. Use Caution/Monitor.
norepinephrine and fenfluramine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - nortriptyline
nortriptyline increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
nortriptyline and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
fenfluramine, nortriptyline. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - olanzapine
olanzapine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
olanzapine decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately. - ondansetron
ondansetron decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately.
- opium tincture
opium tincture increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- orphenadrine
orphenadrine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- oxazepam
oxazepam increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- oxycodone
oxycodone increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- oxymorphone
oxymorphone increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- oxytocin
oxytocin increases effects of fenfluramine by pharmacodynamic synergism. Use Caution/Monitor.
- paliperidone
paliperidone increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
paliperidone decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately. - palonosetron
palonosetron decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately.
- papaveretum
papaveretum increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- papaverine
papaverine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- paroxetine
paroxetine and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
fenfluramine, paroxetine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - pentazocine
pentazocine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
fenfluramine and pentazocine both increase serotonin levels. Use Caution/Monitor. - pentobarbital
pentobarbital increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- perphenazine
perphenazine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
perphenazine, fenfluramine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only. - phendimetrazine
fenfluramine and phendimetrazine both decrease sedation. Use Caution/Monitor.
fenfluramine and phendimetrazine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - phenobarbital
phenobarbital increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
phenobarbital will decrease the level or effect of fenfluramine by Other (see comment). Modify Therapy/Monitor Closely. Coadministration with drugs that increase serotonin may increase the risk of serotonin syndrome. - phentermine
phentermine and fenfluramine both decrease sedation. Use Caution/Monitor.
fenfluramine and phentermine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - phenylephrine
fenfluramine and phenylephrine both decrease sedation. Use Caution/Monitor.
fenfluramine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - phenylephrine PO
fenfluramine and phenylephrine PO both decrease sedation. Use Caution/Monitor.
fenfluramine and phenylephrine PO both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - pholcodine
pholcodine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- pimavanserin
pimavanserin decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately.
- pimozide
pimozide increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- pirbuterol
pirbuterol and fenfluramine both decrease sedation. Use Caution/Monitor.
pirbuterol and fenfluramine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - primidone
primidone increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
primidone will decrease the level or effect of fenfluramine by Other (see comment). Modify Therapy/Monitor Closely. Coadministration with drugs that increase serotonin may increase the risk of serotonin syndrome. - prochlorperazine
prochlorperazine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
prochlorperazine, fenfluramine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only. - promazine
promazine, fenfluramine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
- promethazine
promethazine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
promethazine, fenfluramine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only. - propofol
propofol increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- propylhexedrine
fenfluramine and propylhexedrine both decrease sedation. Use Caution/Monitor.
fenfluramine and propylhexedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - protriptyline
protriptyline increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
protriptyline and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
fenfluramine, protriptyline. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - pseudoephedrine
fenfluramine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.
- quazepam
quazepam increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- quetiapine
quetiapine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
quetiapine decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately. - ramelteon
ramelteon increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- rifampin
rifampin will decrease the level or effect of fenfluramine by Other (see comment). Modify Therapy/Monitor Closely. Coadministration with drugs that increase serotonin may increase the risk of serotonin syndrome.
- risperidone
risperidone increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
risperidone decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately. - rizatriptan
rizatriptan and fenfluramine both increase serotonin levels. Use Caution/Monitor.
fenfluramine, rizatriptan. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - salmeterol
salmeterol and fenfluramine both decrease sedation. Use Caution/Monitor.
salmeterol and fenfluramine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - SAMe
fenfluramine and SAMe both increase serotonin levels. Use Caution/Monitor.
- samidorphan
samidorphan decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately.
- scullcap
scullcap increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- secobarbital
secobarbital increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- selegiline transdermal
selegiline transdermal and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
- serdexmethylphenidate/dexmethylphenidate
serdexmethylphenidate/dexmethylphenidate and fenfluramine both decrease sedation. Use Caution/Monitor.
serdexmethylphenidate/dexmethylphenidate and fenfluramine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - sertraline
sertraline and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
fenfluramine, sertraline. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - sevoflurane
sevoflurane increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- shepherd's purse
shepherd's purse increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- St John's Wort
fenfluramine, St John's Wort. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome.
- sufentanil
sufentanil increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- sumatriptan
sumatriptan and fenfluramine both increase serotonin levels. Use Caution/Monitor.
fenfluramine, sumatriptan. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - sumatriptan intranasal
sumatriptan intranasal and fenfluramine both increase serotonin levels. Use Caution/Monitor.
fenfluramine, sumatriptan intranasal. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - sumatriptan transdermal
fenfluramine, sumatriptan transdermal. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome.
- tapentadol
tapentadol increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- temazepam
temazepam increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- terbutaline
terbutaline and fenfluramine both decrease sedation. Use Caution/Monitor.
terbutaline and fenfluramine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - thioridazine
thioridazine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
thioridazine, fenfluramine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only. - thiothixene
thiothixene increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- topiramate
topiramate increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.
- tramadol
tramadol increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
fenfluramine and tramadol both increase serotonin levels. Use Caution/Monitor. - trazodone
trazodone increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
trazodone and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
fenfluramine, trazodone. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - triazolam
triazolam increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- triclofos
triclofos increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- trifluoperazine
trifluoperazine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
trifluoperazine, fenfluramine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only. - trimipramine
trimipramine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
trimipramine and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
fenfluramine, trimipramine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - triprolidine
triprolidine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- venlafaxine
venlafaxine and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.
fenfluramine, venlafaxine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - vilazodone
fenfluramine, vilazodone. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome.
- vortioxetine
fenfluramine, vortioxetine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome.
- xylometazoline
fenfluramine and xylometazoline both decrease sedation. Use Caution/Monitor.
fenfluramine and xylometazoline both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - yohimbine
yohimbine and fenfluramine both decrease sedation. Use Caution/Monitor.
fenfluramine and yohimbine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - ziconotide
ziconotide increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- ziprasidone
ziprasidone increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
ziprasidone decreases effects of fenfluramine by pharmacodynamic antagonism. Use Caution/Monitor. Potent serotonin receptor antagonists may decrease fenfluramine efficacy. If coadministered, monitor appropriately. - zolmitriptan
zolmitriptan and fenfluramine both increase serotonin levels. Use Caution/Monitor.
fenfluramine, zolmitriptan. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome. - zolmitriptan transdermal
fenfluramine, zolmitriptan transdermal. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome.
Minor (3)
- desmopressin
desmopressin increases effects of fenfluramine by pharmacodynamic synergism. Minor/Significance Unknown.
- eucalyptus
eucalyptus increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Minor/Significance Unknown.
- sage
sage increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Minor/Significance Unknown.
Adverse Effects
>10%
Dravet syndrome
- Decreased appetite (23-49%)
- Diarrhea (15-31%)
- Fatigue, malaise, asthenia (15-30%)
- Somnolence, sedation, lethargy (23-26%)
- Abnormal ECHO (9-23%)
- Pyrexia (5-21%)
- Upper respiratory tract infection (5-21%)
- Blood pressure increased (8-13%)
- Drooling, salivary hypersecretion (8-13%)
- Weight decreased (5-13%)
- Status epilepticus (3-12%)
Lennox-Gastaut syndrome
- Decreased appetite (20-36%)
- Fatigue, malaise, asthenia (14-24%)
- Somnolence, sedation, lethargy (12-22%)
- Diarrhea (11-13%)
- Vomiting (8-14%)
1-10%
Dravet syndrome
- Fall (10%)
- Ataxia, balance disorder, gait disturbance (7-10%)
- Vomiting (5-10%)
- Constipation (3-10%)
- Decreased blood glucose (9%)
- Abnormal behavior (8-9%)
- Ear infection (3-9%)
- Irritability (3-9%)
- Tremor (3-9%)
- Bronchitis (3-9%)
- Hypotonia (8%)
- Headache (8%)
- Rash (5-8%)
- Rhinitis (3-8%)
- Gastroenteritis (2-8%)
- Blood prolactin increased (5%)
- Decreased activity (5%)
- Dehydration (5%)
- Insomnia (5%)
- Stereotypy (5%)
- Contusion (5%)
- Eczema (5%)
- Enuresis (5%)
- Laryngitis (5%)
- Negativism (5%)
- Urinary tract infection (5%)
- Viral infection (5%)
- Croup (3-5%)
- Increased heart rate (3-5%)
- Urinary incontinence (3-5%)
- Chills (2-5%)
Lennox-Gastaut syndrome
- Constipation (6-9%)
- Seizure (5-9%)
- Upper respiratory tract infection (7-8%)
- Irritability (3-8%)
- Weight decreased (2-8%)
Warnings
Black Box Warnings
Valvular heart disease and pulmonary arterial hypertension
- There is an association between serotonergic drugs with 5-HT2B receptor agonist activity, including fenfluramine, and valvular heart disease (VHD) and pulmonary arterial hypertension (PAH)
- Echocardiogram (ECHO) assessments are required before, during, and after treatment
- Consider the benefits versus the risks of initiating or continuing fenfluramine based on ECHO findings
- Owing to risks ofor VHD and PAH, fenfluramine is available only through a restricted program called the Fintepla REMS program
Contraindications
Hypersensitivity to fenfluramine or any of the excipients
Concomitant use of, or within 14 days of, the administration of monoamine oxidase inhibitors (MAOIs)
Cautions
May decrease appetite and weight; monitor weight regularly during treatment and modify dose if decreased weight observed; monitor growth regularly in children
May cause somnolence, sedation, and lethargy; other CNS depressants, including alcohol, could potentiate these effects; advise patients not to drive or operate machinery until they have gained sufficient experience on fenfluramine; somnolence effects may diminish with continued treatment
Antiepileptic drugs (AEDs) increase risk of suicidal thoughts or behavior in patients taking these drugs for any indication; monitor for emergence or worsening of depression, suicidal thoughts or behavior, or any unusual changes in mood or behavior
As with most AEDs, withdraw gradually when discontinuing because of risk for increased seizure frequency and status epilepticus; if withdrawal is needed owing to serious adverse reaction, rapid discontinuation can be considered
Significant increased blood pressure, including hypertensive crisis, reported; monitor blood pressure during treatment
Cardiac monitoring via echocardiogram can identify evidence of valvular heart disease and pulmonary arterial hypertension prior to a patient becoming symptomatic, aiding in early detection of these conditions
May cause mydriasis and can precipitate angle-closure glaucoma; discontinue therapy in patients with acute decrease in visual acuity or ocular pain
VHD and PAH
- Owing to the association between serotonergic drugs with 5-HT2B receptor agonist activity, including fenfluramine, and PAH and VHD, cardiac monitoring is required before initiating treatment, during treatment, and after completion of fenfluramine
- Echocardiograms should be repeated every 6 months, and once 3-6 months post-treatment with this drug
-
Consider benefits versus risks if following signs observed
- Valvular abnormality or new abnormality via ECHO
- VHD as indicated by mild or greater aortic regurgitation or moderate or greater mitral regurgitation, with additional characteristics of VHD (eg, valve thickening, restrictive valve motion)
- PAH as indicated by elevated right heart/pulmonary artery pressure (PASP >35 mm Hg)
Fintepla REMS program
- Further information is available at http://www.FinteplaREMS.com or by telephone at 1-877-964-3649
-
Prescribers
- Must be certified by enrolling in the program
- Must counsel patients receiving fenfluramine regarding risk of VHD and PAH, signs and symptoms of VHD and PAH, cardiac monitoring via ECHO during treatment, and cardiac monitoring after treatment
-
Patients
- Must enroll in the REMS program and comply with ongoing monitoring requirements
-
Pharmacies, wholesalers, and distributers
- Must be certified by enrolling in the REMS program and must only dispense to patients who are authorized to receive treatment
- Wholesalers and distributers must only distribute to certified pharmacies
Drug interaction overview
-
Stiripentol plus clobazam
- Coadministration with stiripentol plus clobazam, with or without valproate, inhibits the metabolism of fenfluramine, thereby increasing fenfluramine plasma concentrations and decreasing its metabolite, norfenfluramine
- Dose adjustment is required for patients taking stiripentol plus clobazam
-
Strong CYP1A2 and CYP2B6 inducers
- Coadministration with rifampin or strong CYP1A2 and CYP2B6 inducers decreases fenfluramine plasma levels and effects
- Consider increasing fenfluramine dosage when coadministered with rifampin or a strong CYP1A2 and CYP2B6 inducer; do not exceed the maximum daily dosage
-
Serotonin receptor antagonists
- Monitor appropriately when coadministered with cyproheptadine or potent 5-HT1A, 5-HT1D, 5-HT2A, or 5-HT2C serotonin receptor antagonists
- Cyproheptadine and potent 5-HT1A, 5-HT1D, 5-HT2A, and 5-HT2C serotonin receptor antagonists may decrease the efficacy of fenfluramine
-
Serotonergic drugs
- Coadministration with MAOIs is contraindicated
- Use with caution in patients taking medications that increase serotonin
- Coadministration with drugs (eg, SSRIs, SNRIs, TCAs) that increase serotonin may increase the risk of serotonin syndrome
Pregnancy & Lactation
Pregnancy
There are no data on use in pregnant women; available data from epidemiologic studies with fenfluramine or dexfenfluramine are insufficient to evaluate for a drug-associated risk of major birth defects, miscarriage, or other adverse maternal or fetal outcomes; this drug can cause decreased appetite and decreased weight; monitor for adequate weight gain during pregnancy
Reproductive potential
- In animal studies, oral administration of fenfluramine resulted in adverse reproductive effects in males and females at clinically relevant doses in the presence of parental toxicity
Animal data
- In animal studies, administration of this drug throughout organogenesis (rat and rabbit) or throughout gestation and lactation (rat) resulted in adverse effects on development (fetal malformations, embryofetal, and offspring mortality, and growth impairment) in presence of maternal toxicity at clinically relevant maternal plasma levels of this drug and its major active metabolite
Pregnancy exposure registry
- Registry monitors pregnancy outcomes in females exposed to AEDs, such as fenfluramine during pregnancy
- Encourage females who are taking fenfluramine during pregnancy to enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry by calling the toll-free number 1-888-233-2334 or visiting http://www.aedpregnancyregistry.org
Lactation
There are no data on presence of this drug or its metabolites in human milk, effects on breastfed infant, or milk production; developmental and health benefits of breastfeeding should be considered along with mother’s clinical need for therapy and any potential adverse effects on breastfed infant from this drug or from underlying maternal condition
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Mechanism of action for the treatment of seizures associated with Dravet syndrome is unknown
Fenfluramine and the metabolite, norfenfluramine, increase extracellular levels of serotonin through interaction with serotonin transporter proteins, and exhibit agonist activity at serotonin 5HT-2 receptors
Absorption
Peak plasma concentration (steady-state): 68 ng/mL
AUC (steady-state): 1390 ng⋅hr/mL
Peak plasma time (steady-state): 4-5 hr
Absolute bioavailability: ~68-74%
Distribution
Vd: 11.9 L/kg
Protein bound: 50%
Metabolism
Primarily metabolized by CYP1A2, CYP2B6, and CYP2D6
Minor extent are CYP2C9, CYP2C19, and CYP3A4/5
Norfenfluramine is then deaminated and oxidized to form inactive metabolites
Elimination
Half-life: 20 hr
Clearance: 24.8 L/hr
Excretion
- Urine: >90% as fenfluramine; <25% of total (norfenfluramine, or other metabolites)
- Feces: <5%
Administration
Oral Administration
Use a calibrated measuring device (either a 3- or 6-mL oral syringe) provided by the pharmacy to measure and administer the prescribed dose accurately; do not use a household teaspoon or tablespoon
Also compatible with commercially available gastric and nasogastric feeding tubes
Storage
Unopened bottle
- Store at room temperature (20-25ºC [68-77ºF]); excursions permitted to 15-30ºC (59-86ºF)
- Do not refrigerate or freeze
- Store the bottle and syringe together
Opened bottle
- Discard any unused portion 3 months after first opening the bottle or the “Discard After” date on the bottle, whichever is sooner
- Do not refrigerate or freeze
- Store the bottle and syringe together
Images
Formulary
Adding plans allows you to compare formulary status to other drugs in the same class.
To view formulary information first create a list of plans. Your list will be saved and can be edited at any time.
Adding plans allows you to:
- View the formulary and any restrictions for each plan.
- Manage and view all your plans together – even plans in different states.
- Compare formulary status to other drugs in the same class.
- Access your plan list on any device – mobile or desktop.
