Classifications: central nervous system agent; anticonvulsant succinimide
Pregnancy Category: D
500 mg capsules
Succinimide derivative reportedly less potent and less effective than other drugs of this class. Reduces the frequency of
Apparently depresses the motor cortex and elevates the threshold of CNS sensitivity to seizure activity, thus lessening the
incidence of seizure activity.
Management of petit mal epilepsy (absence seizures) and with other anticonvulsants when other forms of epilepsy coexist with
Intermittent porphyria; liver or kidney disease; pregnancy (category D), lactation.
Adult/Child: PO 0.51 g b.i.d. or t.i.d.
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.
Drug: Carbamazepine decreases phensuximide levels; isoniazid significantly increases phensuximide levels; levels of both phenobarbital and phensuximide may be altered with increased seizure frequency.
Absorption: Readily absorbed from GI tract. Peak: 14 h. Metabolism: Metabolized in liver. Elimination: Excreted slowly in urine; small amounts excreted in bile and feces. Half-Life: 512 h.
- Give consistently with respect to time of day.
Assessment & Drug Effects
- Monitor weight, especially in children, since anorexic effects of drug might cause weight loss.
- Lab tests: Perform baseline and periodic liver and kidney function tests. Perform periodic blood tests, especially with long-term
Patient & Family Education
- Report onset of skin rash or other unusual symptoms to physician.
- Be aware that phensuximide may color urine pink, red, or red-brown.
- Do not use OTC drugs unless the physician approves; loss of seizure control can be induced by ingredients in some popular
- Do not drive or engage in potentially hazardous activities until response to drug is known.
- Do not breast feed while taking this drug.