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Table 2 Pharmacokinetics characteristics of AEDs which may increase the probability of problems associated with their generic substitution

From: Potential problems and recommendations regarding substitution of generic antiepileptic drugs: a systematic review of literature

AEDs Therapeutic range Pharmacokinetics parameters
Narrow therapeutic range Low water solubility Nonlinear pharmacokinetics
Carbamazepine 4–12 μg/ml Yes Yes Yes
Phenytoin 10–20 μg/ml Yes Yes Yes
Valproate 50–100 μg/ml Yes No Yes
Phenobarbital 20–40 μg/ml Yes No No
Ethosuximide 40–100 μg/ml Yes No Yes
Gabapentin 4–20 μg/ml Yes No Yes
Lamotrigine 4–20 μg/ml No Yes No
Levetiracetam 5–40 μg/ml Yes No No
Oxcarbazepine 10–40 μg/ml Yes Yes No
Topiramate 10–20 μg/ml Yes Yes No
Tiagibine 100–300 ng/ml Yes No No
Vigabatrin 0.8–36 μg/ml Yes No No
Primidone 5–10 μg/ml Yes Yes No
Felbamate 30–100 μg/ml Yes Yes No
Zonisamide 10–40 μg/ml Yes Yes Yes