Sodium channel Agents (FETT)

Anticonvulsants

CARBAMAZEPINE

Phenytoin

• First-line treatment for focal seizures

• First-line treatment of trigeminal neuralgia

• Second-line treatment for generalized tonic-clonic seizures

• Inactivates Na+ channels

• Nausea

• Rash

• Hyponatremia, hyperhydration, and edema (due to SIADH)

• DRESS syndrome

• Blood count abnormalities (e.g., agranulocytosis, aplastic anemia)

• Teratogenicity during the first trimester (cleft lip/palate, spina bifida) (see pharmacotherapy during pregnancy)

• Diplopia

• Ataxia

• Hepatotoxicity

• Stevens-Johnson syndrome

• Induces cytochrome P450

• Pregnancy (especially valproate and carbamazepine)

• Strong induction of cytochrome P450

• Tonic-clonic seizures

• Only rarely used for long-term treatment of focal seizures

• Treatment of established status epilepticus[2

• Inactivation of Na+ channels

• Zero-order elimination (i.e., constant rate of drug eliminated

• Hirsutism

• Hyperpigmentation of skin (melasma)

• Gingival hyperplasia

• Nystagmus

• Osteopenia

• Megaloblastic anemia due to ↓ folate absorption

• Peripheral neuropathy

• Stevens-Johnson syndrome

• Drug-induced lupus erythematosus

• DRESS syndrome

• Intoxication: sedation, diplopia, ataxia, arrhythmias

• Induction of cytochrome P-450 enzymes

• Teratogenic: fetal hydantoin syndrome

• Hypothyroidism

You can use the following to remember the features of PHENYTOIN: cytochrome P-450 interaction, Hirsutism, Enlarged gums (gingival hyperplasia), Nystagmus, Yellow-browning of skin (melasma), Teratogenicity, Osteomalacia, Interacts with folate, Neuropathy

Pregnancy

• Induction of cytochrome P450