PHENSUXIMIDE
(fen-sux'i-mide)
Milontin
Classifications: central nervous system agent; anticonvulsant succinimide
Prototype: Ethosuximide
Pregnancy Category: D

Availability

500 mg capsules

Actions

Succinimide derivative reportedly less potent and less effective than other drugs of this class. Reduces the frequency of epileptiform attacks.

Therapeutic Effects

Apparently depresses the motor cortex and elevates the threshold of CNS sensitivity to seizure activity, thus lessening the incidence of seizure activity.

Uses

Management of petit mal epilepsy (absence seizures) and with other anticonvulsants when other forms of epilepsy coexist with petit mal.

Contraindications

Intermittent porphyria; liver or kidney disease; pregnancy (category D), lactation.

Route & Dosage

Absence Seizures
Adult/Child: PO 0.5–1 g b.i.d. or t.i.d.

Administration

Oral

Adverse Effects (1%)

Body as a Whole: Drowsiness, dizziness, ataxia, muscle weakness, flushing, periorbital edema, GI: Anorexia, nausea, vomiting. Urogenital: Reversible nephropathy. Hematologic: Granulocytopenia. Skin: Alopecia, pruritus, skin rash.

Interactions

Drug: Carbamazepine decreases phensuximide levels; isoniazid significantly increases phensuximide levels; levels of both phenobarbital and phensuximide may be altered with increased seizure frequency.

Pharmacokinetics

Absorption: Readily absorbed from GI tract. Peak: 1–4 h. Metabolism: Metabolized in liver. Elimination: Excreted slowly in urine; small amounts excreted in bile and feces. Half-Life: 5–12 h.

Nursing Implications

Assessment & Drug Effects

Patient & Family Education


Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug