ethosuximide

Contraindicated in:

Hypersensitivity;
History of ethosuximide-induced immune thrombocytopenia;

Use Cautiously in:

All patients (may ↑ risk of suicidal thoughts/behaviors);
Mixed seizure disorders (may ↑ risk of grand mal seizures);
Bone marrow suppression;
Renal impairment;
Hepatic impairment;
OB: Use during pregnancy only if potential maternal benefit justifies potential fetal risk;
Lactation: Use while breastfeeding only if potential maternal benefit justifies potential risk to infant.
Pedi: Children <3 yr (safety and effectiveness not established).

Adv. Reactions/Side Effects ⬆ ⬇

Derm: DRUG REACTION WITH EOSINOPHILIA AND SYSTEMIC SYMPTOMS (DRESS), hirsutism, rash, STEVENS-JOHNSON SYNDROME (SJS), urticaria

EENT: myopia

GI: abdominal pain, anorexia, cramping, diarrhea, hiccups, nausea, vomiting, weight loss

GU: pink/brown discoloration of urine, vaginal bleeding

Hemat: agranulocytosis, eosinophilia, immune thrombocytopenia, leukopenia, pancytopenia

Neuro: ↑FREQUENCY OF TONIC-CLONIC (GRAND MAL) SEIZURES, ataxia, dizziness, drowsiness, euphoria, fatigue, headache, hyperactivity, irritability, psychiatric disturbances, SUICIDAL THOUGHTS

Misc: ALLERGIC REACTION, systemic lupus erythematosus

Interactions ⬆ ⬇

Drug-drug:

Seizure threshold may be lowered by phenothiazines, antidepressants, or MAO inhibitors.
Additive CNS depression with other CNS depressants, including alcohol, antihistamines, antidepressants, opioid analgesics, and sedative/hypnotics.
May ↑ levels and risk of toxicity of phenytoin .
May ↓ levels and effectiveness of phenobarbital or primidone.
Levels may be ↑ or ↓ by valproic acid.

Drug-Natural Products:

St. John's wort may ↓ levels and effectiveness; avoid concurrent use.
Kava, valerian, skullcap, chamomile, or hops can ↑ risk of CNS depression.

Route/Dosage ⬆ ⬇

PO (Adults and Children >6 yr): 250 mg twice daily initially; may ↑ by 250 mg/day every 4–7 days until control achieved (usual maintenance dose 20–40 mg/kg/day in 2 divided doses).
PO (Children 3–6 yr): 250 mg once daily initially; may ↑ by 250 mg/day every 4–7 days until control achieved (optimal dose for most children is 20 mg/kg/day in 2 divided doses).

Availability ⬆ ⬇

(Generic available)

Capsules: 250 mg
Oral solutionraspberry flavor: 250 mg/5 mL

Assessment ⬆ ⬇

Assess location, duration, frequency, and characteristics of seizure activity.
Assess patient’s mood, behavioral patterns, and affect. Patients with a history of psychiatric disorders have an ↑ risk of developing behavioral changes. These symptoms may necessitate withdrawal of the medication.
Assess for suicidal tendencies. Monitor closely for changes in behavior that could indicate the emergence or worsening of suicidal thoughts or behavior or depression.
Monitor patients for development of severe cutaneous adverse reactions, including DRESS and SJS including signs/symptoms of prodrome of fever, malaise, mucosal lesions, progressive skin rash, blisters, lymphadenopathy, conjunctivitis, myalgias, hepatitis, and/or eosinophilia. If a severe cutaneous adverse reaction is suspected, hold ethosuximide until etiology of reaction is determined. If a severe cutaneous adverse reaction is confirmed, or for other Grade 4 skin reactions, permanently discontinue ethosuximide.

Lab Test Considerations:

Monitor CBC, hepatic function tests, and urinalysis routinely during prolonged therapy.

Toxicity and Overdose:

Therapeutic serum ethosuximide levels range from 40–100 mcg/mL.

Implementation ⬆ ⬇

PO: Measure liquid preparations with calibrated measuring device.
- Administer with food or milk to ↓ GI irritation.

Patient/Family Teaching ⬆ ⬇

Explain the purpose and side effects of ethosuximide. Instruct patient to take as directed. If a dose is missed, take as soon as remembered within 4 hr, then continue on dose schedule. Do not double doses. Do not discontinue medication without advice of health care professional. Sudden withdrawal may precipitate seizures. Instruct patient to read the Medication Guide before starting and with each Rx refill, changes may occur.
Emphasize the importance of follow-up exams to monitor progress and side effects.
Medication may cause dizziness, drowsiness, or blurred vision. Caution patient to avoid driving or other activities requiring alertness until response to medication is known. Do not resume driving until physician gives clearance based on control of seizure disorder.
Advise patient to avoid alcohol while taking this medication.
Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and consult health care professional before taking any new medications.
May cause depression or suicide. Instruct patients and caregivers to monitor for emergence of suicidal thoughts and behaviors. Notify health care professional immediately if suicidal thoughts, new or worsening depression, anxiety, changes in behavior or mood, thoughts of suicide, dying, or hurting self, or acting on dangerous impulses occur. Instruct patient to carry wallet card and to call the National Suicide Prevention Lifeline at 1-800-273-8255 or visit www.988lifeline.org if they experience suicidal thoughts.
Instruct patient to notify health care professional if skin rash, joint pain, sore throat, fever, unusual bleeding or bruising, swollen glands, or pink/brown urine, or signs/symptoms of DRESS occur.
Medical ID describing disease process and medication regimen should be worn at all times in case of emergencies.
Rep: Advise women of reproductive potential to notify health care professional if pregnancy is planned or suspected or if breastfeeding. Folic acid should be prescribed to women taking ethosuximide pre-conceptionally and during pregnancy to ↓ the risk for neurodevelopmental disorders and neural tube defects. If symptoms such as sedation, poor suckling, or hyperexcitability are observed in nursing infants, measuring infant serum concentrations is advisable. Encourage patient to enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry if they become pregnant by calling 1-888-233-2334.

ROUTE	ONSET	PEAK	DURATION
PO	hr–days	days	days

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇

Action ⬆ ⬇

Pharmacokinetics ⬆ ⬇

Time/Action Profile ⬆ ⬇

Contraind./Precautions ⬆ ⬇