The dosing information presented in this table applies to young adults. Physicians treating children or elderly patients may need to modify the dosing regimens. See the prescribing information and other pages of this site for specifics.

carbamazepine (Tegretol, Tegretol-XR, Carbatrol)

Percent bound to plasma protein Elimination half-life (hours) Time to steady state (days) Frequency of dosing Therapeutic level (mcg/mL)
70-80 11-17 (chronic therapy) 3-10 bid-qid 4-12

 

 

ethosuximide (Zarontin)

Percent bound to plasma protein Elimination half-life (hours) Time to steady state (days) Frequency of dosing Therapeutic level (mcg/mL)
0 40-50 6-12 qd-bid 40-100

 

 

felbamate (Felbatol)

Felbamate is recommended for use only by patients who respond inadequately to alternative treatments and whose epilepsy is so severe that a substantial risk of aplastic anemia, liver failure, or both is deemed acceptable in light of the benefits of its use.

Percent bound to plasma protein Elimination half-life (hours) Time to steady state (days) Frequency of dosing Therapeutic level (mcg/mL)
25 20-23 5-10 tid-qid not established

 

 

gabapentin (Neurontin)

Percent bound to plasma protein Elimination half-life (hours) Time to steady state (days) Frequency of dosing Therapeutic level (mcg/mL)
0 5-7 (increases with decreased creatinine clearance) 1-2 tid-qid not established

 

 

lamotrigine (Lamictal)

Percent bound to plasma protein Elimination half-life (hours) Time to steady state (days) Frequency of dosing Therapeutic level (mcg/mL)
50-55 With enzyme-inducing AED: 10-15 5-15 With enzyme-inducing AED: bid 3-14 With valproate: 40-60 With valproate: qd-bid

 

 

phenobarbital

Percent bound to plasma protein Elimination half-life (hours) Time to steady state (days) Frequency of dosing Therapeutic level (mcg/mL)
40-60 30-50 16-21 qd 15-40

 

 

phenytoin (Dilantin, Phenytek)

Percent bound to plasma protein Elimination half-life (hours) Time to steady state (days) Frequency of dosing Therapeutic level (mcg/mL)
90 15-30 5-15 qd or bid 10-20

 

 

valproate (Depakote, Depakote ER, Depakene, valproic acid)

Percent bound to plasma protein Elimination half-life (hours) Time to steady state (days) Frequency of dosing Therapeutic level (mcg/mL)
60-95 (decreases with serum levels >100 mcg/mL 6-18 2-4 bid or tid 50-150

Adapted from: Schachter SC. Treatment of seizures. In: Schachter SC, Schomer DL, eds. The comprehensive evaluation and treatment of epilepsy. San Diego, CA: Academic Press; 1997. p. 61-74. With permission from Elsevier (www.elsevier.com).

Authored By: 
Steven C. Schachter MD
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