Precautions and Contraindications
Ethosuximide shares the toxic potentials of the succinimide-derivative anticonvulsants, and the usual precautions of anticonvulsant administration should be observed.
An increased risk of suicidality (suicidal behavior or ideation) was observed in an analysis of studies using various anticonvulsants compared with placebo.(See Suicidality Risk under Cautions: Nervous System Effects.) Patients who are currently receiving or beginning therapy with any anticonvulsant for any indication should be closely monitored for the emergence or worsening of depression, suicidal thoughts or behavior (suicidality), and/or unusual changes in mood or behavior. Clinicians should inform patients, their families, and caregivers of the potential for an increased risk of suicidality and to pay close attention to any day-to-day changes in mood, behavior, and actions; since changes can happen very quickly, it is important to be alert to any sudden differences. In addition, patients, family members, and caregivers should be aware of common warning signs that may signal suicide risk (e.g., talking or thinking about wanting to hurt oneself or end one's life, withdrawing from friends and family, becoming depressed or experiencing worsening of existing depression, becoming preoccupied with death and dying, giving away prized possessions). If these or any new and worrisome behaviors occur, the responsible clinician should be contacted immediately. Clinicians who prescribe ethosuximide or any other anticonvulsant should balance the risk of suicidality with the risk of untreated illness. Epilepsy and many other illnesses for which anticonvulsants are prescribed are themselves associated with an increased risk of morbidity and mortality and an increased risk of suicidal thoughts and behavior. If suicidal thoughts and behavior emerge during anticonvulsant therapy, the clinician must consider whether the emergence of these symptoms in any given patient may be related to the illness being treated.
Ethosuximide should be discontinued at the first sign of a rash (unless the rash is clearly not drug related); if manifestations are suggestive of Stevens-Johnson syndrome, the drug should not be resumed and alternative therapies should be considered. If signs and symptoms of multi-organ hypersensitivity (DRESS) occur during ethosuximide therapy, patients should be evaluated immediately; if an alternative cause cannot be identified, the drug should be discontinued.(See Cautions: Dermatologic and Sensitivity Reactions.)
Patients should be warned that ethosuximide may impair their ability to perform activities requiring mental alertness or physical coordination (e.g., operating machinery, driving a motor vehicle).
Ethosuximide should be used with extreme caution in patients with hepatic impairment, abnormal liver function test values, and/or renal impairment.(See Dosage and Administration.) Complete blood cell counts, liver function tests, and urinalyses should be performed periodically in patients receiving the drug.
Ethosuximide is contraindicated in patients with known hypersensitivity to ethosuximide or other succinimides (e.g., methsuximide, phensuximide [no longer commercially available in the US]).