Ethosuximide


Concise Prescribing Info
Indications/Uses
Absence seizures.
Dosage/Direction for Use
Adult : PO Initial: 500 mg/day in divided doses, increased in increments of 250 mg at 4-7 days interval. Usual dose: 1-1.5 g/day. Max: 2 g/day.
Dosage Details
Oral
Absence seizures
Adult: Initially, 500 mg daily in 2 divided doses, may increase in increments of 250 mg at 4-7 days interval. Usual dose: 1-1.5 g daily in 2 divided doses. Max: up to 2 g daily.
Child: <6 yr Initially, 250 mg daily, may increase gradually in small increments every few days to a usual dose of 20 mg/kg daily. Max: 1 g daily; ≥6 yr Same as adult dose.
Administration
May be taken with or without food.
Contraindications
Hypersensitivity w/ ethosuximide.
Special Precautions
Hepatic or renal impairment. Pregnancy and lactation.
Adverse Reactions
Significant: Mental depression w/ suicidal intentions, SLE.
Nervous: Drowsiness, headache, fatigue, dizziness, ataxia, irritability, euphoria, hyperactivity, lethargy, sleep disturbances, night terrors, aggressiveness, inability to concentrate, paranoid psychosis, increased libido.
GI: Anorexia, wt loss, vague gastric upset, cramps, abdominal pain, diarrhoea, nausea, vomiting, epigastric distress, gum hypertrophy, swelling of the tongue.
Resp: Hiccups.
Genitourinary: Vag bleeding, microscopic hematuria.
Ophthalmologic: Myopia.
Dermatologic: Urticaria, pruritic erythematous rashes, hirsutism.
Potentially Fatal: Blood dyscrasias (e.g. leucopoenia, eosinophilia, agranulocytosis, pancytopaenia w/ or w/o bone marrow depression), aplastic anaemia, drug reaction w/ eosinophilia and systemic symptoms (DRESS), toxic epidermal necrolysis. Rarely, Stevens-Johnson syndrome.
Patient Counseling Information
Avoid abrupt withdrawal. May impair ability to drive or operate machinery.
MonitoringParameters
Monitor seizure frequency, trough serum concentration, platelets, and signs of rash and suicidality. Monitor CBC, liver enzymes, and urinalysis periodically.
Overdosage
Symptoms: Nausea, vomiting, CNS depression (e.g. coma w/ resp depression). Management: Symptomatic and supportive treatment. Induce emesis, perform gastric lavage, or administer activated charcoal and purgatives.
Drug Interactions
Increased plasma concentration and risk of toxicity w/ isoniazid, valproic acid. Antagonised effect w/ antidepressants, antipsychotics. Decreased plasma concentration w/ carbamazepine, phenobarbital, phenytoin.
Action
Description: Ethosuximide, a succinimide derivative, suppresses paroxysmal spike-and-wave pattern common to absence seizure. It depresses nerve transmission in the motor cortex and increases seizure threshold, hence reducing the frequency of epileptiform attack.
Pharmacokinetics:
Absorption: Readily absorbed from the GI tract. Time to peak serum concentration: 1-7 hr.
Distribution: Widely distributed throughout the body. Crosses placenta and enters breast milk. Volume of distribution: 0.7 L/kg.
Metabolism: Extensively hydroxylated in the liver to 3 inactive metabolites.
Excretion: Via urine (mainly as metabolites; 12-20% as unchanged drug). Elimination half-life: 50-60 hr.
Chemical Structure

Chemical Structure Image
Ethosuximide

Source: National Center for Biotechnology Information. PubChem Database. Ethosuximide, CID=3291, https://pubchem.ncbi.nlm.nih.gov/compound/Ethosuximide (accessed on Jan. 23, 2020)

Storage
Store between 20-25°C.
MIMS Class
ATC Classification
N03AD01 - ethosuximide ; Belongs to the class of succinimide derivatives antiepileptics.
References
Anon. Ethosuximide. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 09/03/2017.

Buckingham R (ed). Ethosuximide. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 09/03/2017.

Ethosuximide Capsule (Greenstone LLC). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 09/03/2017.

Joint Formulary Committee. Ethosuximide. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 09/03/2017.

McEvoy GK, Snow EK, Miller J et al (eds). Ethosuximide. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 09/03/2017.

Disclaimer: This information is independently developed by MIMS based on Ethosuximide from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2020 MIMS. All rights reserved. Powered by MIMS.com
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