Dosing & Uses
Dosage Forms & Strengths
tablets
- 400 mg
- 600 mg
oral suspension
- 600 mg/5 mL
Seizures
Monotherapy
- 1200 mg/day PO divided q6-8hr initially; titrate previously untreated patients with caution, increasing the dose in 600 mg increments q2weeks to 2400 mg/day based on clinial response and thereafter to 3600 mg/day if necessary
Conversion to monotherapy
- Initial: 1200 mg/day PO divided q6-8hr; reduce dose of concomitant anticonvulsant(s) by 33% at initiation of felbamate therapy
- Week 2: Increase felbamate dose to 2400 mg/day while reducing the dosage of other anticonvulsant(s) up to an additional 33% of original dosage
- Week 3: Increase felbamate dose up to 3600 mg/day and continue to reduce dosage of other anticonvulsant(s) as clinically indicated
Adjunctive therapy
- Initial: 1200 mg/day PO divided q6-8hr; increase by 1200 mg/day once per week up to 3600 mg/day PO divided q6-8hr
- Decrease concomitant dose of carbamazepine, phenytoin, phenobarbital, or valproic acid by 20 % when intiating felbamate dosing; as felbamate dose is increased, further dosage reductions of concomitant anticonvulsant therapies may be necessary
Renal Impairment
Decreased intial and maintenance doses by 50%
Hepatic Impairment
Contraindicated
Dosage Forms & Strengths
tablets
- 400 mg
- 600 mg
oral suspension
- 600 mg/5mL
Seizures
<14 years: Safety and efficacy not established
>14 years:
Monotherapy
- 1200 mg/day PO divided q6-8hr initially; titrate previously untreated patients with caution, increasing the dose in 600 mg increments q2weeks to 2400 mg/day based on clinial response and thereafter to 3600 mg/day if necessary
Conversion to monotherapy
- Initial: 1200 mg/day PO divided q6-8hr; reduce dose of concomitant anticonvulsant(s) by 33% at initiation of felbamate therapy
- Week 2: Increase felbamate dose to 2400 mg/day while reducing the dosage of other anticonvulsant(s) up to an additional 33% of original dosage
- Week 3: Increase felbamate dose up to 3600 mg/day and continue to reduce dosage of other anticonvulsant(s) as clinically indicated
Adjunctive therapy
- Initial: 1200 mg/day PO divided q6-8hr; increase by 1200 mg/day once per week up to 3600 mg/day PO divided q6-8hr
- Decrease concomitant dose of carbamazepine, phenytoin, phenobarbital, or valproic acid by 20 % when intiating felbamate dosing; as felbamate dose is increased, further dosage reductions of concomitant anticonvulsant therapies may be necessary
Lennox-Gastaut Adjunctive Therapy
<2 years
- Safety and efficacy not established
2-14 years
- Initial: 15 mg/kg/day PO divided q6-8hr
- May increase to by 15 mg/kg/day qWeek to 45 mg/kg/day
- Decrease concomitant dose of carbamazepine, phenytoin, phenobarbital, or valproic acid by 20 % when intiating felbamate dosing; as felbamate dose is increased, further dosage reductions of concomitant anticonvulsant therapies may be necessary
Interactions
Interaction Checker
No Results
Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor
Contraindicated (0)
Serious - Use Alternative (27)
- apalutamide
apalutamide will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of apalutamide, a strong CYP3A4 inducer, with drugs that are CYP3A4 substrates can result in lower exposure to these medications. Avoid or substitute another drug for these medications when possible. Evaluate for loss of therapeutic effect if medication must be coadministered. Adjust dose according to prescribing information if needed.
- atazanavir
atazanavir will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- clarithromycin
clarithromycin will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- clopidogrel
felbamate decreases effects of clopidogrel by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug. Clopidogrel efficacy may be reduced by drugs that inhibit CYP2C19. Inhibition of platelet aggregation by clopidogrel is entirely due to an active metabolite. Clopidogrel is metabolized to this active metabolite in part by CYP2C19. .
- cobicistat
cobicistat will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- darunavir
darunavir will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- enzalutamide
enzalutamide will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- fexinidazole
fexinidazole will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Fexinidazole inhibits CYP3A4. Coadministration may increase risk for adverse effects of CYP3A4 substrates.
- idelalisib
idelalisib will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Idelalisib is a strong CYP3A inhibitor; avoid coadministration with sensitive CYP3A substrates
- indinavir
indinavir will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- itraconazole
itraconazole will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- ivosidenib
ivosidenib will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP3A4 substrates with ivosidenib or replace with alternate therapies. If coadministration is unavoidable, monitor patients for loss of therapeutic effect of these drugs.
- lopinavir
lopinavir will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- mefloquine
mefloquine increases toxicity of felbamate by QTc interval. Avoid or Use Alternate Drug. Mefloquine may enhance the QTc prolonging effect of high risk QTc prolonging agents.
- metoclopramide intranasal
felbamate, metoclopramide intranasal. Either increases effects of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Avoid use of metoclopramide intranasal or interacting drug, depending on importance of drug to patient.
- mifepristone
mifepristone will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- nefazodone
nefazodone will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- nelfinavir
nelfinavir will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- olopatadine intranasal
felbamate 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.
- pacritinib
felbamate will decrease the level or effect of pacritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- posaconazole
posaconazole will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- rifampin
rifampin will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- ritonavir
ritonavir will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- saquinavir
saquinavir will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- tucatinib
tucatinib will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of tucatinib with CYP3A substrates, where minimal concentration changes may lead to serious or life-threatening toxicities. If unavoidable, reduce CYP3A substrate dose according to product labeling.
- ulipristal
felbamate will decrease the level or effect of ulipristal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- voxelotor
voxelotor will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Voxelotor increases systemic exposure of sensitive CYP3A4 substrates. Avoid coadministration with sensitive CYP3A4 substrates with a narrow therapeutic index. Consider dose reduction of the sensitive CYP3A4 substrate(s) if unable to avoid.
Monitor Closely (79)
- acrivastine
acrivastine and felbamate both increase sedation. Use Caution/Monitor.
- amisulpride
amisulpride and felbamate both increase sedation. Use Caution/Monitor.
- amitriptyline
felbamate will increase the level or effect of amitriptyline by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
- asenapine
asenapine and felbamate both increase sedation. Use Caution/Monitor.
- asenapine transdermal
asenapine transdermal and felbamate both increase sedation. Use Caution/Monitor.
- atogepant
felbamate will decrease the level or effect of atogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- avapritinib
avapritinib and felbamate both increase sedation. Use Caution/Monitor.
- axitinib
felbamate decreases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- belzutifan
belzutifan will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. If unable to avoid coadministration of belzutifan with sensitive CYP3A4 substrates, consider increasing the sensitive CYP3A4 substrate dose in accordance with its prescribing information.
- benzhydrocodone/acetaminophen
benzhydrocodone/acetaminophen and felbamate both increase sedation. Use Caution/Monitor.
- bosentan
bosentan will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- brexanolone
brexanolone, felbamate. Either increases toxicity of the other by sedation. Use Caution/Monitor.
- brexpiprazole
brexpiprazole and felbamate both increase sedation. Use Caution/Monitor.
- brimonidine
brimonidine and felbamate both increase sedation. Use Caution/Monitor.
- brivaracetam
brivaracetam and felbamate both increase sedation. Use Caution/Monitor.
- buprenorphine subdermal implant
buprenorphine subdermal implant and felbamate both increase sedation. Use Caution/Monitor.
- buprenorphine transdermal
buprenorphine transdermal and felbamate both increase sedation. Use Caution/Monitor.
- buprenorphine, long-acting injection
buprenorphine, long-acting injection and felbamate both increase sedation. Use Caution/Monitor.
- carbamazepine
carbamazepine decreases levels of felbamate by increasing metabolism. Use Caution/Monitor. Toxicity increased with combination.
carbamazepine will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. - carvedilol
felbamate will increase the level or effect of carvedilol by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
- cenobamate
cenobamate will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP3A4 substrate, as needed, when coadministered with cenobamate.
cenobamate, felbamate. Either increases effects of the other by sedation. Use Caution/Monitor. - crofelemer
crofelemer increases levels of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Crofelemer has the potential to inhibit CYP3A4 at concentrations expected in the gut; unlikely to inhibit systemically because minimally absorbed.
- dabrafenib
dabrafenib will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
- daridorexant
felbamate 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.
- deutetrabenazine
felbamate and deutetrabenazine both increase sedation. Use Caution/Monitor.
- dichlorphenamide
dichlorphenamide and felbamate both decrease serum potassium. Use Caution/Monitor.
- dienogest/estradiol valerate
felbamate will decrease the level or effect of dienogest/estradiol valerate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Advise women to use alternative method of contraception or back-up method when moderate or weak enzyme inducer is used with combination contraceptives. Back-up contraception should be continued for 28 days after discontinuing medication to ensure contraceptive reliability.
- difelikefalin
difelikefalin and felbamate both increase sedation. Use Caution/Monitor.
- duvelisib
duvelisib will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with duvelisib increases AUC of a sensitive CYP3A4 substrate which may increase the risk of toxicities of these drugs. Consider reducing the dose of the sensitive CYP3A4 substrate and monitor for signs of toxicities of the coadministered sensitive CYP3A substrate.
- efavirenz
efavirenz will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- elagolix
elagolix decreases levels of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak-to-moderate CYP3A4 inducer. Monitor CYP3A substrates if coadministered. Consider increasing CYP3A substrate dose if needed.
- elvitegravir/cobicistat/emtricitabine/tenofovir DF
elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP3A4 inhibitor; contraindicated with CYP3A4 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.
- encorafenib
encorafenib, felbamate. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Encorafenib both inhibits and induces CYP3A4 at clinically relevant plasma concentrations. Coadministration of encorafenib with sensitive CYP3A4 substrates may result in increased toxicity or decreased efficacy of these agents.
- escitalopram
felbamate will increase the level or effect of escitalopram by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
- esketamine intranasal
esketamine intranasal, felbamate. Either increases toxicity of the other by sedation. Use Caution/Monitor.
- ethotoin
felbamate will increase the level or effect of ethotoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
- etravirine
felbamate will increase the level or effect of etravirine by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
felbamate will increase the level or effect of etravirine by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
etravirine will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. - fedratinib
fedratinib will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary.
- fosphenytoin
felbamate will increase the level or effect of fosphenytoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
fosphenytoin will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. - ganaxolone
felbamate and ganaxolone both increase sedation. Use Caution/Monitor.
- ibuprofen IV
felbamate will increase the level or effect of ibuprofen IV by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
- iloperidone
iloperidone increases levels of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Iloperidone is a time-dependent CYP3A inhibitor and may lead to increased plasma levels of drugs predominantly eliminated by CYP3A4.
- imipramine
felbamate will increase the level or effect of imipramine by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
- isavuconazonium sulfate
felbamate will decrease the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- istradefylline
istradefylline will increase the level or effect of felbamate by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of CYP3A4 substrates in clinical trials. This effect was not observed with istradefylline 20 mg/day. Consider dose reduction of sensitive CYP3A4 substrates.
istradefylline will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of CYP3A4 substrates in clinical trials. This effect was not observed with istradefylline 20 mg/day. Consider dose reduction of sensitive CYP3A4 substrates. - ketoconazole
ketoconazole will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- lasmiditan
lasmiditan, felbamate. Either increases effects of the other by sedation. Use Caution/Monitor. Coadministration of lasmiditan and other CNS depressant drugs, including alcohol have not been evaluated in clinical studies. Lasmiditan may cause sedation, as well as other cognitive and/or neuropsychiatric adverse reactions.
- lemborexant
felbamate, lemborexant. Either increases effects of the other by sedation. Modify Therapy/Monitor Closely. Dosage adjustment may be necessary if lemborexant is coadministered with other CNS depressants because of potentially additive effects.
- lenacapavir
lenacapavir will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lencapavir (a moderate CYP3A4 inhibitor) may increase CYP3A4 substrates initiated within 9 months after last SC dose of lenacapavir, which may increase potential risk of adverse reactions of CYP3A4 substrates.
- levoketoconazole
levoketoconazole will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- levonorgestrel intrauterine
felbamate decreases levels of levonorgestrel intrauterine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- levonorgestrel oral
felbamate decreases levels of levonorgestrel oral by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- linagliptin
felbamate will increase the level or effect of linagliptin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Use of alternative treatments is strongly recommended when linagliptin is to be administered with a CYP3A4 inducer
- lorlatinib
lorlatinib will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- losartan
felbamate will increase the level or effect of losartan by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. May inhibit the conversion of losartan to its active metabolite E-3174. Importance of interaction not established; monitor individual therapeutic response to determine losartan dosage.
- lurasidone
lurasidone, felbamate. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Potential for increased CNS depressant effects when used concurrently; monitor for increased adverse effects and toxicity.
- mavacamten
felbamate will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.
- methylphenidate transdermal
methylphenidate transdermal will increase the level or effect of felbamate 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 intranasal
midazolam intranasal, felbamate. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase the risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.
- mitotane
mitotane decreases levels of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Mitotane is a strong inducer of cytochrome P-4503A4; monitor when coadministered with CYP3A4 substrates for possible dosage adjustments.
- nafcillin
nafcillin will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- nateglinide
felbamate will increase the level or effect of nateglinide by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
- nevirapine
nevirapine will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- orlistat
orlistat decreases levels of felbamate by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Risk of convulsions.
- parecoxib
felbamate will increase the level or effect of parecoxib by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
- phenobarbital
phenobarbital will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- phenytoin
felbamate will increase the level or effect of phenytoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
phenytoin will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Felbamate may increase serum concentrations of phenytoin. Phenytoin, a CYP3A4 inducer, may decrease plasma levels of felbamate (a CYP3A4 substrate). - primidone
primidone will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
- ribociclib
ribociclib will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- rifabutin
rifabutin will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- rifapentine
rifapentine will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- rucaparib
rucaparib will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP3A4 substrates, if clinically indicated.
- secobarbital
secobarbital will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. May also enhance CNS depressant effect of felbamate
- sevelamer
sevelamer decreases levels of felbamate by increasing elimination. Use Caution/Monitor.
- stiripentol
stiripentol, felbamate. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP3A4 inhibitor and inducer. Monitor CYP3A4 substrates coadministered with stiripentol for increased or decreased effects. CYP3A4 substrates may require dosage adjustment.
stiripentol, felbamate. Either increases effects of the other by sedation. Use Caution/Monitor. Concomitant use stiripentol with other CNS depressants, including alcohol, may increase the risk of sedation and somnolence. - tazemetostat
tazemetostat will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
felbamate will decrease the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. - tecovirimat
tecovirimat will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.
- ubrogepant
felbamate will decrease the level or effect of ubrogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Dose adjustment is recommended with concomitant use of ubrogepant and moderate and weak CYP3A4 inducers. (see Dosage Modifications)
- voriconazole
voriconazole will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
Minor (41)
- acetaminophen
felbamate decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
- acetaminophen IV
felbamate decreases levels of acetaminophen IV by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
- acetaminophen rectal
felbamate decreases levels of acetaminophen rectal by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
- acetazolamide
acetazolamide will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- alosetron
felbamate will increase the level or effect of alosetron by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.
- anastrozole
anastrozole will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- atracurium
felbamate decreases effects of atracurium by pharmacodynamic antagonism. Minor/Significance Unknown.
- biotin
felbamate decreases levels of biotin by unspecified interaction mechanism. Minor/Significance Unknown. Biotin supplementation may be necessary.
- bosentan
felbamate will increase the level or effect of bosentan by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.
- celecoxib
felbamate will increase the level or effect of celecoxib by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.
- cimetidine
felbamate will increase the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.
- cisatracurium
felbamate decreases effects of cisatracurium by pharmacodynamic antagonism. Minor/Significance Unknown.
- cyanocobalamin
felbamate decreases levels of cyanocobalamin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- cyclophosphamide
cyclophosphamide will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- dexmethylphenidate
dexmethylphenidate increases effects of felbamate by decreasing metabolism. Minor/Significance Unknown.
- diazepam
felbamate will increase the level or effect of diazepam by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.
- diclofenac
felbamate will increase the level or effect of diclofenac by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.
- ethinylestradiol
felbamate decreases levels of ethinylestradiol by unknown mechanism. Minor/Significance Unknown.
- ethotoin
ethotoin decreases levels of felbamate by increasing metabolism. Minor/Significance Unknown. Toxicity increased with combination.
- flurbiprofen
felbamate will increase the level or effect of flurbiprofen by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.
- fosphenytoin
fosphenytoin decreases levels of felbamate by increasing metabolism. Minor/Significance Unknown. Toxicity increased with combination.
- ibuprofen
felbamate will increase the level or effect of ibuprofen by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.
- larotrectinib
larotrectinib will increase the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- levocarnitine
felbamate decreases levels of levocarnitine by unspecified interaction mechanism. Minor/Significance Unknown.
- losartan
felbamate decreases effects of losartan by decreasing metabolism. Minor/Significance Unknown. May inhibit the conversion of losartan to its active metabolite E-3174. Importance of interaction not established; monitor individual therapeutic response to determine losartan dosage.
- meloxicam
felbamate will increase the level or effect of meloxicam by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.
- mestranol
felbamate decreases levels of mestranol by unknown mechanism. Minor/Significance Unknown.
- onabotulinumtoxinA
felbamate decreases effects of onabotulinumtoxinA by pharmacodynamic antagonism. Minor/Significance Unknown.
- pancuronium
felbamate decreases effects of pancuronium by pharmacodynamic antagonism. Minor/Significance Unknown.
- phenobarbital
felbamate increases levels of phenobarbital by decreasing metabolism. Minor/Significance Unknown.
- piroxicam
felbamate will increase the level or effect of piroxicam by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.
- rapacuronium
felbamate decreases effects of rapacuronium by pharmacodynamic antagonism. Minor/Significance Unknown.
- rocuronium
felbamate decreases effects of rocuronium by pharmacodynamic antagonism. Minor/Significance Unknown.
- sage
sage decreases effects of felbamate by pharmacodynamic antagonism. Minor/Significance Unknown. Theoretical interaction; some species of sage may cause convulsions.
- serdexmethylphenidate/dexmethylphenidate
serdexmethylphenidate/dexmethylphenidate increases effects of felbamate by decreasing metabolism. Minor/Significance Unknown.
- succinylcholine
felbamate decreases effects of succinylcholine by pharmacodynamic antagonism. Minor/Significance Unknown.
- sulfamethoxazole
felbamate will increase the level or effect of sulfamethoxazole by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.
- tolbutamide
felbamate will increase the level or effect of tolbutamide by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.
- valproic acid
valproic acid increases levels of felbamate by decreasing metabolism. Minor/Significance Unknown.
- vecuronium
felbamate decreases effects of vecuronium by pharmacodynamic antagonism. Minor/Significance Unknown.
- voriconazole
felbamate will increase the level or effect of voriconazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.
felbamate will increase the level or effect of voriconazole by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.
Adverse Effects
>10%
Adjunctive therapy
- Nausea (34.2%)
- Vomiting (16.7%)
- Constipation (11.4%)
- Dyspepsia (12.3%)
- Anorexia (19.3%)
- Dyspepsia (12.3%)
Lennox-Gastaut
- Anorexia (55%)
- Somnolence (48%)
- URI (46-50%)
- Vomiting (39%)
- Nervousness (16-20%)
- Insomnia (16.1%)
- Purpura (11-15%)
- Fever (22.6%)
- Constipation (12.9%)
1-10%
Monotherapy
- Acne (3.4%)
- Anxiety (5.2%)
- Constipation (6.9%)
- Diarrhea (5.2%)
- Diplopia (3.4%)
- Dyspepsia (8.6%)
- Face edema (3.4%)
- Fatigue (6.9%)
- Headache (6.9%)
- Insomnia (8.6%)
- Intramenstrual bleeding (3.4%)
- Otitis media (3.4%)
- Rash (3.4%)
- Urinary tract infection (3.4%)
- Vomiting (8.6%)
Adjunctive therapy
- Abdominal pain (5.3%)
- Abnormal gait (5.3%)
- Anxiety (5.3%)
- Ataxia (3.5%)
- Depression (5.3%)
- Increased ALT (3.5%)
- Diarrhea (5.3%)
- Dry mouth (2.6%)
- Diplopia (6-10%)
- Paresthesia (3.5%)
- Pharyngitis (2.6%)
- Stupor (2.6%)
- Sinusitis (2-5%)
- Tremor (6.1%)
- Upper respiratory infection (5.3%)
Lennox-Gastaut
- Abnormal gait (9.7%)
- Abnormal thoughts (6.5%)
- Ataxia (6.5%)
- Dyspepsia (6.5%)
- Emotional lability (6.5%)
- Fatigue (9.7%)
- Headache (6.5%)
- Hiccup (9.7%)
- Leukopenia (6.5%)
- Miosis (6.5%)
- Nausea (6.5%)
- Coughing (6.5%)
- Pain (6.5%)
- Pharyngitis (9.7%)
- Otitis media (6-10%)
<1%
Atrial arrhythmia
Bradycardia
Hypotension
Thrombophlebitis
Cerebral edema
Coma
Alopecia
Jaundice
Hepatic failure
Rigors
Rhabdomyolysis
Warnings
Black Box Warnings
Aplastic anemia associated with felbamate use. Risk 100-fold in felbamate-treated patients compared with untreated population.
May be fatal. Use only in patients with severe epilepsy in whom risk of aplastic anemia is acceptable.
Acute liver failure reported with use; initiate use in patients with normal liver function.
Contraindications
Hypersensitivity to carbamates; history of blood dyscrasia, hepatic impairment
Cautions
Increased risk of suicidal behavior reported with anticonvulsant use; monitor patients for changes in behavior that might indicate suicidal behavior
Associated with increased incidence of aplastic anemia and acute hepatic failure , use only when alternative therapy is unsuitable and benefits outweigh risks
Use caution in renal impairment
Not for use as first line therapy in epilepsy; for use when benefits outweigh risks
Do not discontinue therapy abruptly
Pregnancy & Lactation
Pregnancy Category: C
Lactation: Excreted in milk; not recommended
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 is unknown. Has weak inhibitory effects on GABA-receptor binding and benzodiazepine receptor binding.
Pharmacokinetics
Half-Life: 20-23 hr
Peak Plasma: 17-49 mcg/mL (dose-dependent)
Peak serum time: 3-5 hr
Bioavailability: High
Protein bound: 22-25%
Vd: 756 mL/kg
Metabolism: Liver
Metabolites: Inactive
Total body clearance: 26 mL/hr/kg (single dose); 30 mL/hr/kg (mult. doses)
Excretion: Urine (80-90%)
Enzyme induced: CYP3A4
Enzyme inhibited: hepatic CYP2C19
Images
| BRAND | FORM. | UNIT PRICE | PILL IMAGE |
|---|---|---|---|
| Felbatol oral - | 600 mg/5 mL suspension |  | |
| Felbatol oral - | 600 mg tablet |  | |
| Felbatol oral - | 600 mg/5 mL suspension |  | |
| Felbatol oral - | 400 mg tablet |  | |
| felbamate oral - | 400 mg tablet |  | |
| felbamate oral - | 600 mg/5 mL suspension |  | |
| felbamate oral - | 400 mg tablet |  | |
| felbamate oral - | 600 mg tablet |  | |
| felbamate oral - | 600 mg/5 mL suspension |  | |
| felbamate oral - | 600 mg/5 mL suspension |  | |
| felbamate oral - | 400 mg tablet |  | |
| felbamate oral - | 600 mg/5 mL suspension |  | |
| felbamate oral - | 600 mg tablet |  | |
| felbamate oral - | 600 mg tablet |  | |
| felbamate oral - | 600 mg/5 mL suspension |  | |
| felbamate oral - | 600 mg tablet |  | |
| felbamate oral - | 400 mg tablet |  | |
| felbamate oral - | 600 mg/5 mL suspension |  | |
| felbamate oral - | 600 mg/5 mL suspension |  | |
| felbamate oral - | 600 mg/5 mL suspension |  | |
| felbamate oral - | 600 mg/5 mL suspension |  |
Copyright © 2010 First DataBank, Inc.
Patient Handout
felbamate oral
FELBAMATE - ORAL
(fel-BAM-ate)
COMMON BRAND NAME(S): Felbatol
WARNING: Severe (sometimes fatal) blood/bone marrow problems (such as low red/white blood cells and platelets) and liver problems have occurred with felbamate. Felbamate should be used only by people with severe seizures (epilepsy) that cannot be controlled with other medications. Do not use this drug if you have liver problems. Discuss the risks and benefits with your doctor before starting felbamate.Tell your doctor right away if you have signs of infection (such as sore throat that doesn't go away, fever, chills), signs of anemia (such as unusual tiredness), easy bruising/bleeding, or signs of liver problems (such as nausea/vomiting that doesn't stop, stomach/abdominal pain, yellowing eyes/skin, dark urine). Usually, people who have liver problems while taking this drug should not start taking it again.Your doctor will check certain blood tests (liver function, complete blood count) and may have you see a doctor who treats blood/bone marrow problems before you start felbamate and while you use this drug. Blood/bone marrow problems may also occur after you stop taking the drug. Blood tests may be needed for some time after you stop taking felbamate. Keep all medical and lab appointments.
USES: Felbamate is used to treat severe seizures. This medication should be used only when you cannot take other medications or when other medications have not been able to control your seizures. Felbamate is known as an anticonvulsant or anti-epileptic drug.
HOW TO USE: Read and sign the Informed Consent form provided by your doctor. Read the Medication Guide provided by your pharmacist before you start taking felbamate and each time you get a refill. If you have any questions, ask your doctor or pharmacist before starting felbamate.Take this medication by mouth with or without food as directed by your doctor, usually 3 to 4 times a day. Take with food or milk if stomach upset occurs.If you are using the liquid form of this medication, shake the bottle well before each dose. Carefully measure the dose using a special measuring device/spoon. Do not use a household spoon because you may not get the correct dose.The dosage is based on your medical condition and response to treatment. For children, the dosage is also based on weight. To reduce your risk of side effects, your doctor may direct you to start this medication at a low dose and gradually increase your dose.Take this medication regularly to get the most benefit from it. To help you remember, take it at the same times each day.Do not stop taking this medication without consulting your doctor. Seizures may become worse when this drug is suddenly stopped. Your dose may need to be gradually decreased.If you are already taking other anti-seizure medications, carefully follow your doctor's directions for adjusting the dose of these other medications when you start taking felbamate.Tell your doctor if your seizures get worse.
SIDE EFFECTS: See also Warning section.Drowsiness, dizziness, nausea, vomiting, diarrhea, constipation, trouble sleeping, loss of coordination, headache, blurred/double vision, hiccups, or loss of appetite may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Tell your doctor right away if you have any serious side effects, including: fainting.A small number of people who take anticonvulsants for any condition (such as seizure, bipolar disorder, pain) may experience depression, suicidal thoughts/attempts, or other mental/mood problems. Tell your doctor right away if you or your family/caregiver notice any unusual/sudden changes in your mood, thoughts, or behavior such as signs of depression, suicidal thoughts/attempts, thoughts about harming yourself.A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
PRECAUTIONS: Before taking felbamate, tell your doctor or pharmacist if you are allergic to it; or to meprobamate; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: blood/bone marrow disorders (such as anemia, bleeding problems, low white blood cell count), liver disease, kidney disease, mental/mood disorders (such as depression, suicidal thoughts).This drug may make you dizzy or drowsy or blur your vision. It may also cause double vision. Alcohol or marijuana (cannabis) can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness or clear vision until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).Older adults may be more sensitive to the side effects of this drug, especially dizziness, loss of coordination, or fainting. These side effects can increase the risk of falling.During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.This medication passes into breast milk. Because of the possible risk to the infant, breast-feeding while using this drug is not recommended. Consult your doctor before breast-feeding.
DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.Some products that may interact with this drug include: clopidogrel, orlistat.This medication may decrease the effectiveness of hormonal birth control such as pills, patch, or ring. This could cause pregnancy. Discuss with your doctor or pharmacist if you should use reliable backup birth control methods while using this medication. Also tell your doctor if you have any new spotting or breakthrough bleeding, because these may be signs that your birth control is not working well.Tell your doctor or pharmacist if you are taking other products that cause drowsiness including alcohol, marijuana (cannabis), antihistamines (such as cetirizine, diphenhydramine), drugs for sleep or anxiety (such as alprazolam, diazepam, zolpidem), muscle relaxants (such as carisoprodol, cyclobenzaprine), and opioid pain relievers (such as codeine, hydrocodone).Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely.
OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.
NOTES: Do not share this medication with others.Lab and/or medical tests (such as complete blood count, kidney/liver tests) should be done before, during, and after treatment with this medication. See also Warning section.
MISSED DOSE: If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.
STORAGE: Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
MEDICAL ALERT: Your condition can cause complications in a medical emergency. For information about enrolling in MedicAlert, call 1-888-633-4298 (US) or 1-800-668-1507 (Canada).
Information last revised August 2021. Copyright(c) 2023 First Databank, Inc.
IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.
Formulary
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Adding plans allows you to:
- View the formulary and any restrictions for each plan.
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