Antiepileptic drugs and breastfeeding

Table 2 Main pharmacokinetic characteristics of antiepileptic drugs

	PB^†	Oral	T ½^§	M/P^¶
		Oral	(hours)
		Bioavailability^‡	(hours)
	(%)	(%)
Carbamazepine	74	100	18 – 54	0.69
Clonazepam	50 – 86	100	18 – 50	0.33
Diazepam	99	100	43	0.2 – 2.7
Ethosuximide	NA	100	30 – 60	0.94
Gabapentin	< 3	50 – 60	5 – 7	0.7 – 1.3
Lamotrigine	55	98	29	0.057 – 1.47 [33]
Levetiracetam	< 10	100	6 – 8	0.76 – 1.55 [37, 38]
Oxcarbazepine	40	100	9 (oxcarbazepine metabolyte)	0.5
Phenobarbital	51	80 – 100	20 – 133	0.4 – 0.6
Phenobarbital	51	80 – 100	(45–500 in newborns) [41]	0.4 – 0.6
Phenytoin	89	70 – 100	6 – 24	0.18 – 0.45
Phenytoin	89	70 – 100	(20–160 in preterm infants) [48]	0.18 – 0.45
Pregabalin	NA	90	6	NA
Primidone	25	90	5 – 18	0.72
Tiagabine	96	90	7 – 9	NA
Topiramate	15	75	18 – 24	0.86 – 1.1 [55]
Valproate	94	100	14	0.42
Vigabatrin	NA	50	7	< 1
Zonisamide	40	NA	63	0.93

^† PB: maternal plasma protein binding expressed as percentage.
^‡ Oral Bioavailability: intestinal absorption after oral administration expressed as percentage of the administered dose.
^§ T ½: half-life of the drug.
^¶ M/P: milk to plasma ratio of a drug concentration.
Data drawn from references 1–8 except where otherwise specified. NA: indicates that no data are available.

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