antimalarials (artemether) (with lumefantrine). Avoid.

Study

▶ Antimalarials (pyrimethamine) increase the risk of

haematological toxicity when given with antiepileptics

(fosphenytoin, phenytoin).rStudy

▶ Antimalarials (pyrimethamine) are predicted to increase the risk

of haematological toxicity when given with antiepileptics

(phenobarbital, primidone).rTheoretical

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the

concentration of

Theoretical

antimalarials (piperaquine). Avoid.o ▶ Antiepileptics (carbamazepine, phenobarbital, primidone)

potentially increase the risk of toxicity when given with

antimalarials (quinine).qStudy

▶ Apalutamide potentially decreases the exposure to valproate.

nTheoretical

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to moderately decrease

the exposure to

Study

apixaban. Use with caution or avoid.r

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) moderately decrease the exposure to

apremilast. Avoid.rStudy

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to markedly decrease the

exposure to aprepitant. Avoid.oStudy

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to moderately decrease

the exposure to

o

aripiprazole. Adjust aripiprazole dose, p. 395.

Study → Also see TABLE 11 p. 1377

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to axitinib. Avoid or adjust dose.oStudy

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to bazedoxifene.oTheoretical

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) decrease the exposure to bedaquiline.

Avoid.rStudy → Also see TABLE 1 p. 1375

▶ Antiepileptics (phenobarbital, primidone) are predicted to

decrease the exposure to beta blockers, non-selective (carvedilol,

labetalol).oTheoretical

▶ Antiepileptics (phenobarbital, primidone) are predicted to

decrease the exposure to beta blockers, non-selective

(propranolol).oStudy

▶ Antiepileptics (phenobarbital, primidone) are predicted to

decrease the exposure to beta blockers, selective (acebutolol,

bisoprolol, metoprolol, nebivolol).oStudy

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to bictegravir. Avoid.oStudy

▶ Oxcarbazepine is predicted to decrease the exposure to

bictegravir. Avoid.oTheoretical

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) slightly decrease the exposure to

bortezomib. Avoid.rStudy → Also see TABLE 12 p. 1378

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone)

r

affect the exposure to bosentan. Avoid.

Study

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to very markedly decrease

the exposure to bosutinib. Avoid.rStudy

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to brigatinib. Avoid.rStudy

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to markedly decrease the

exposure to bupropion.rStudy

▶ Valproate increases the exposure to bupropion.rStudy

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to buspirone. Use with caution and adjust dose.rStudy

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) moderately decrease the exposure to

cabozantinib. Avoid.oStudy

▶ Antiepileptics (fosphenytoin, phenytoin) are predicted to

moderately increase the clearance of caffeine citrate. Monitor

and adjust dose.oStudy

▶ Calcium channel blockers (diltiazem) increase the concentration

of carbamazepine and carbamazepine is predicted to decrease

the exposure to calcium channel blockers (diltiazem). Monitor

concentration and adjust dose.rAnecdotal

▶ Calcium channel blockers (verapamil) increase the concentration

of carbamazepine and carbamazepine is predicted to decrease

the exposure to

Anecdotal

calcium channel blockers (verapamil).r

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to calcium channel blockers (amlodipine, felodipine, lacidipine,

lercanidipine, nicardipine, nifedipine, nimodipine). Monitor and

adjust dose.oStudy

▶ Antiepileptics (phenobarbital, primidone) are predicted to

decrease the exposure to calcium channel blockers (diltiazem,

verapamil).rStudy

▶ Calcium channel blockers (diltiazem, verapamil) potentially

increase the concentration of antiepileptics (fosphenytoin,

phenytoin) and antiepileptics (fosphenytoin, phenytoin) are

predicted to decrease the exposure to calcium channel blockers

(diltiazem, verapamil).rStudy

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to cannabis extract. Avoid.rTheoretical → Also see TABLE 11

p. 1377

▶ Capecitabine increases the concentration of antiepileptics

(fosphenytoin, phenytoin).rAnecdotal

▶ Carbapenems

r

decrease the concentration of valproate. Avoid.

Anecdotal

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to cariprazine. Avoid.rTheoretical → Also see TABLE 11

p. 1377

▶ Antiepileptics (carbamazepine, fosphenytoin, phenytoin) are

predicted to decrease the concentration of caspofungin. Adjust

caspofungin dose, p. 592.oTheoretical

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to ceritinib. Avoid.rStudy

▶ Antiepileptics (phenobarbital, primidone) are predicted to affect

the ef

o

ficacy of chenodeoxycholic acid. Monitor and adjust dose.

Theoretical

▶ Antiepileptics (phenobarbital, primidone) decrease the

concentration of chloramphenicol.oStudy

▶ Intravenous chloramphenicol increases the concentration of

antiepileptics (fosphenytoin, phenytoin) and antiepileptics

(fosphenytoin, phenytoin) affect the concentration of

intravenous chloramphenicol. Monitor concentration and

adjust dose.rStudy

▶ Chlordiazepoxide affects the concentration of antiepileptics

(fosphenytoin, phenytoin).rStudy

▶ Phenobarbital

o

decreases the effects of cholic acid. Avoid.

Study

BNF 78 Antiepileptics — Antiepileptics 1393

Interactions | Appendix 1

A1

Antiepileptics (continued)

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) decrease the concentration of

ciclosporin.rStudy

▶ Oxcarbazepine

r

decreases the concentration of ciclosporin.

Anecdotal

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to alter the effects of

cilostazol.oTheoretical

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to cinacalcet. Monitor and adjust dose.oStudy

▶ Carbamazepine is predicted to increase the risk of

haematological toxicity when given with oral

o

cladribine.

Theoretical

▶ Clobazam potentially affects the concentration of antiepileptics

(fosphenytoin, phenytoin).rAnecdotal

▶ Stiripentol

Study

increases the concentration of clobazam.r

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) decrease the exposure to clomethiazole.

Monitor and adjust dose.oStudy → Also see TABLE 11

p. 1377

▶ Clonazepam potentially affects the concentration of

antiepileptics (fosphenytoin, phenytoin).rAnecdotal

▶ Antiepileptics (fosphenytoin, phenobarbital, phenytoin,

primidone) are predicted to decrease the exposure to

clozapine.oAnecdotal → Also see TABLE 11 p. 1377

▶ Carbamazepine is predicted to increase the risk of

myelosuppression when given with

Anecdotal

clozapine. Avoid.r

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to cobicistat. Avoid.rTheoretical

▶ Oxcarbazepine is predicted to decrease the concentration of

cobicistat.rTheoretical

▶ Cobicistat is predicted to very slightly increase the exposure to

perampanel.nStudy

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to cobimetinib. Avoid.rTheoretical

▶ Antiepileptics (carbamazepine, eslicarbazepine, fosphenytoin,

oxcarbazepine, perampanel, phenobarbital, phenytoin,

primidone, rufinamide, topiramate) are predicted to decrease

the efficacy of combined hormonal contraceptives. For FSRH

guidance, see Contraceptives, interactions p. 794.rStudy

▶ Combined hormonal contraceptives alter the exposure to

lamotrigine. Adjust dose.oStudy

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to corticosteroids (budesonide, deflazacort, dexamethasone,

fludrocortisone, hydrocortisone, methylprednisolone,

prednisolone, triamcinolone)

o

. Monitor and adjust dose.

Study

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to corticosteroids (fluticasone).qTheoretical

▶ Antiepileptics (fosphenytoin, phenytoin) are predicted to alter

the anticoagulant effect of coumarins.oAnecdotal

▶ Antiepileptics (phenobarbital, primidone) decrease the

anticoagulant effect of coumarins. Monitor INR and adjust

dose.oStudy

▶ Carbamazepine decreases the effects of coumarins. Monitor

and adjust dose.rStudy

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to markedly decrease the

exposure to crizotinib. Avoid.rStudy

▶ Carbamazepine is predicted to decrease the exposure to

dabigatran. Avoid.rStudy

▶ Phenytoin is predicted to decrease the exposure to dabigatran.

Avoid.rTheoretical

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to dabrafenib. Avoid.oTheoretical

▶ Danazol moderately increases the concentration of

carbamazepine. Monitor and adjust dose.rStudy

▶ Antiepileptics (fosphenytoin, phenobarbital, phenytoin,

primidone) are predicted to increase the risk of

methaemoglobinaemia when given with

Theoretical

dapsone.r

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to darifenacin.oTheoretical

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to dasabuvir. Avoid.rTheoretical

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to markedly decrease the

exposure to dasatinib. Avoid.rStudy

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to slightly decrease the

exposure to delamanid. Avoid.oStudy

▶ Lamotrigine is predicted to increase the risk of hyponatraemia

when given with desmopressin.rTheoretical

▶ Antiepileptics (carbamazepine, eslicarbazepine, fosphenytoin,

oxcarbazepine, perampanel, phenobarbital, phenytoin,

primidone, rufinamide, topiramate) are predicted to decrease

the efficacy of desogestrel. For FSRH guidance, see

Contraceptives, interactions p. 794.rTheoretical

▶ Desogestrel is predicted to increase the exposure to

lamotrigine.oStudy

▶ Diazepam potentially affects the concentration of antiepileptics

(fosphenytoin, phenytoin). Monitor concentration and adjust

dose.rStudy

▶ Diazoxide decreases the concentration of antiepileptics

(fosphenytoin, phenytoin) and antiepileptics (fosphenytoin,

phenytoin) are predicted to decrease the effects of diazoxide.

Monitor concentration and adjust dose.oAnecdotal

▶ Antiepileptics (fosphenytoin, phenytoin) are predicted to

decrease the concentration of digoxin.oAnecdotal

▶ Disulfiram increases the concentration of antiepileptics

(fosphenytoin, phenytoin). Monitor concentration and adjust

dose.rStudy → Also see TABLE 12 p. 1378

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) decrease the exposure to dolutegravir.

Adjust dose.rStudy

▶ Oxcarbazepine is predicted to decrease the exposure to

dolutegravir. Adjust dose.rTheoretical

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to doravirine. Avoid.rStudy

▶ Oxcarbazepine is predicted to decrease the exposure to

doravirine. Avoid.rTheoretical

▶ Phenytoin

o

is predicted to decrease the exposure to duloxetine.

Theoretical

▶ Carbamazepine is predicted to decrease the exposure to

edoxaban.oStudy

▶ Phenytoin

o

is predicted to decrease the exposure to edoxaban.

Theoretical

▶ Antiepileptics (fosphenytoin, phenytoin) slightly decrease the

exposure to efavirenz and efavirenz affects the concentration

of antiepileptics (fosphenytoin, phenytoin).rTheoretical

▶ Carbamazepine slightly decreases the exposure to efavirenz

and efavirenz slightly decreases the exposure to

carbamazepine.rStudy

▶ Phenobarbital is predicted to decrease the exposure to

efavirenz and efavirenz affects the concentration of

phenobarbital.rTheoretical

▶ Efavirenz is predicted to affect the efficacy of primidone and

primidone is predicted to slightly decrease the exposure to

efavirenz.rTheoretical

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to elbasvir. Avoid.rStudy

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to eliglustat. Avoid.rStudy

1394 Antiepileptics — Antiepileptics BNF 78

Interactions | Appendix 1

A1

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the

concentration of elvitegravir. Avoid.rTheoretical

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to encorafenib.rTheoretical

▶ Enteral feeds

Study

decrease the absorption of phenytoin.r

▶ Enzalutamide is predicted to slightly decrease the exposure to

brivaracetam.oTheoretical

▶ Enzalutamide is predicted to decrease the exposure to

perampanel. Monitor and adjust dose.oStudy

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the effects of

ergotamine.oTheoretical

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to erlotinib. Avoid or adjust erlotinib dose, p. 979.rStudy

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to esketamine. Adjust dose.oTheoretical → Also see

TABLE 11 p. 1377

▶ Antiepileptics (carbamazepine, eslicarbazepine, fosphenytoin,

oxcarbazepine, perampanel, phenobarbital, phenytoin,

primidone, rufinamide, topiramate) are predicted to decrease

the efficacy of etonogestrel. For FSRH guidance, see

Contraceptives, interactions p. 794.rTheoretical

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the efficacy of

etoposide.oStudy

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to etravirine. Avoid.rTheoretical

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the

concentration of everolimus. Avoid or adjust dose.rStudy

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) moderately decrease the exposure to

exemestane.oStudy

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to fesoterodine. Avoid.oStudy

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to fingolimod.oStudy

▶ Fluorouracil increases the concentration of antiepileptics

(fosphenytoin, phenytoin). Monitor concentration and adjust

dose.rAnecdotal

▶ Folates are predicted to decrease the concentration of

antiepileptics (fosphenytoin, phenobarbital, phenytoin,

primidone)

Study

. Monitor concentration and adjust dose.r

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to fosaprepitant. Avoid.oTheoretical

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to gefitinib. Avoid.rStudy

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to moderately decrease

the exposure to glecaprevir. Avoid.rStudy

▶ Antiepileptics (eslicarbazepine, oxcarbazepine) potentially

decrease the exposure to glecaprevir. Avoid.rTheoretical

▶ Valproate potentially opposes the effects of glycerol

phenylbutyrate.oTheoretical

▶ Grapefruit juice slightly increases the exposure to

carbamazepine. Monitor and adjust dose.oStudy

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the exposure

to grazoprevir. Avoid.rStudy

▶ Antiepileptics (phenobarbital, primidone) decrease the effects of

griseofulvin.oStudy

▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,

phenytoin, primidone) are predicted to decrease the

o

concentration of guanfacine. Adjust guanfacine dose, p. 352.

Study → Also see TABLE 11 p. 1377

▶ Oxcarbazepine is predicted to decrease the concentration of

guanfacine

o