Table 16.3.

Characteristics of antiepileptic drugs (AEDs)

AED	Usual dosage (mg/day)	Plasma therapeutic range (mg/L)	Common/important side-effects	Main mechanism of action	Oral bioavailability (%)	Metabolism and excretion	T_1/2 (h)	Protein binding (%)
CBZ	400–1600	4–12	Leukopenia, hepatotoxicity, hyponatremia, SJS/TEN	Na⁺-channel blocker	75–85	Hepatic epoxidation, conjugation	5–26	75
CZP	0.5–40	0.02–0.08	Sedation, cognitive effects, drowsiness	GABA-receptor agonist	90	Hepatic reduction and acetylation	20–60	85
CLB	5–40	0.3–3.0	Sedation, cognitive effects, drowsiness	GABA-receptor agonist	85	Hepatic demethylation, hydroxylation	18–40	85
LCM	200–400	10–20	Dizziness, headache, nausea, diplopia, blurred vision, cognitive dysfunction, skin reactions	Slow Na⁺-channel blocker	>95	Hepatic demethylation, unchanged renal excretion (40%)	13	<15
LTG	200–600	5–15	Rash, SJS/TEN, DRESS, headache, ataxia	Na⁺-channel blocker	>95	Hepatic glucuronidation, renal excretion (10%)	12–60	55
LEV	1000–3000	5–30	Somnolence, asthenia, irritabililty, psychosis	Binding to synaptic vesicle protein 2 (SV2A)	>95	Partially hydrolyzed in blood, renal excretion (65%)	5–11	None
OXC	900–2400	10–35	Somnolence, headache, diplopia, SJS, bone marrow suppression, hyponatremia	Na⁺-channel blocker	>95	Hydroxylation, glucuronidation	8–15	38
PB	30–180	15–40	Rash, hepatotoxicity, impaired cognition, ataxia, mood change, SJS/TEN	GABA-receptor agonist, glutamate antagonist, Na⁺-Ca⁺-blocker	80–100	Hepatic oxidation, hydroxylation, conjugation	46–136	45–60
PHT	150–400	10–20	Blood dyscrasia, hepatitis, SJS, gum hyperplasia, lupus-like reactions, hirsutism	Na⁺-channel blocker	95 95	Hepatic oxidation, hydroxylation, conjugation	24–72	85–95
PGB	150–600	2–8	Somnolence, dizziness, ataxia	Ca⁺-channel blocker	90	No metabolism, renal excretion	5–7	None
TPM	100–500	2–20	Impaired cognition, hepatotoxicity, weight loss, renal calculi	Na⁺-channel blocker, GABA-receptor agonist, NMDA receptor blocker	80–95%	No metabolism, mainly renal excretion	20–30	80
VPA	500–2500	50–100	Hepatotoxicity, thrombo- and neutropenia, tremor, weight gain, hair loss, ovarian cystic syndrome	GABA-receptor agonist, Na⁺-channel blocker, Glutaminergic inhibitor	>95	Hepatic glucuronidation, oxidation, conjugation	8–15	85–95
ZON	200–600	20–30	Somnolence, ataxia, dizziness, renal calculi	Na⁺- and Ca⁺-channel blocker	>95	Hepatic acetylation, glucuronidation (20%), renal excretion (30%)	50–70	40–50

DRESS, drug reactions with eosinophilia and systemic symptoms; Na⁺, sodium; NMDA, N-methyl-D-aspartate; Ca⁺, calcium; K⁺, potassium; CBZ, carbamazepine; CLB, clobazam; CZP, clonazepam; GABA, gamma-aminobutyric acid; LCM, lacosamide; LEV, levetiracetam; LTG, lamotrigine; OXC, oxcarbazepine; PB, phenobarbitone; PGB, pregabalin; PHT, phenytoin; SJS, Stevens-Johnson syndrome; TEN, toxic epidermal necrolysis; TPM, topiramate; VPA, valproic acid; ZON, zonisamide.