methsuximide (Rx)

Brand and Other Names:Celontin
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Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

capsule

  • 150mg
  • 300mg

Absence Seizures

Initial: 300 mg PO qDay

May increase by 300 mg/week; not to exceed 1.2 g/day in divided doses

Monitor: CBC

Dosage Forms & Strengths

capsule

  • 150mg
  • 300mg

Absence Seizures

<12 years: Not established

≥12 years

  • Initial: 300 mg PO qDay
  • May increase by 300 mg/week; not to exceed 1.2 g/day in divided doses
  • Monitor: CBC
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Interactions

Interaction Checker

and methsuximide

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    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

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            Contraindicated (0)

              Serious - Use Alternative (3)

              • apalutamide

                apalutamide will decrease the level or effect of methsuximide by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug. Coadministration of apalutamide, a strong CYP2C19 inducer, with drugs that are CYP2C19 substrates can result in lower exposure to these medications. Avoid or substitute another drug for these medications when possible. Evaluate for loss of therapeutic effect if medication must be coadministered.

              • lonafarnib

                lonafarnib will increase the level or effect of methsuximide by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug. Lonafarnib may increase the AUC and peak concentration of CYP2C19 substrates. If coadministration unavoidable, monitor for adverse reactions and reduce the CYP2C19 substrate dose in accordance with its approved product labeling.

              • metoclopramide intranasal

                methsuximide, metoclopramide intranasal. Either increases effects of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Avoid use of metoclopramide intranasal or interacting drug, depending on importance of drug to patient.

              Monitor Closely (19)

              • brexanolone

                brexanolone, methsuximide. Either increases toxicity of the other by sedation. Use Caution/Monitor.

              • cannabidiol

                cannabidiol will increase the level or effect of methsuximide by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider reducing the dose of sensitive CYP2C19 substrates, as clinically appropriate, when coadministered with cannabidiol.

              • cenobamate

                cenobamate will increase the level or effect of methsuximide by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider a dose reduction of CYP2C19 substrates, as clinically appropriate, when used concomitantly with cenobamate.

              • deutetrabenazine

                methsuximide and deutetrabenazine both increase sedation. Use Caution/Monitor.

              • elagolix

                elagolix will increase the level or effect of methsuximide by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak CYP2C19 inhibitor. Caution with sensitive CYP2C19 substrates.

              • eslicarbazepine acetate

                eslicarbazepine acetate will increase the level or effect of methsuximide by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.

              • fedratinib

                fedratinib will increase the level or effect of methsuximide by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP2C19 substrates as necessary.

              • fexinidazole

                fexinidazole will increase the level or effect of methsuximide by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.

              • lasmiditan

                lasmiditan, methsuximide. Either increases effects of the other by sedation. Use Caution/Monitor. Coadministration of lasmiditan and other CNS depressant drugs, including alcohol have not been evaluated in clinical studies. Lasmiditan may cause sedation, as well as other cognitive and/or neuropsychiatric adverse reactions.

              • lemborexant

                lemborexant, methsuximide. Either increases effects of the other by sedation. Modify Therapy/Monitor Closely. Dosage adjustment may be necessary if lemborexant is coadministered with other CNS depressants because of potentially additive effects.

              • lumacaftor/ivacaftor

                lumacaftor/ivacaftor, methsuximide. affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. In vitro studies suggest that lumacaftor may induce and ivacaftor may inhibit CYP2C19 substrates. .

              • lurasidone

                lurasidone, methsuximide. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Potential for increased CNS depressant effects when used concurrently; monitor for increased adverse effects and toxicity.

              • midazolam intranasal

                midazolam intranasal, methsuximide. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase the risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.

              • orlistat

                orlistat decreases levels of methsuximide by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Risk of convulsions.

              • rucaparib

                rucaparib will increase the level or effect of methsuximide by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP2C19 substrates, if clinically indicated.

              • sevelamer

                sevelamer decreases levels of methsuximide by increasing elimination. Use Caution/Monitor.

              • stiripentol

                stiripentol will increase the level or effect of methsuximide by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider reducing the dose of CYP2C19 substrates, if adverse reactions are experienced when administered concomitantly with stiripentol.

                stiripentol, methsuximide. Either increases effects of the other by sedation. Use Caution/Monitor. Concomitant use stiripentol with other CNS depressants, including alcohol, may increase the risk of sedation and somnolence.

              • tecovirimat

                tecovirimat will increase the level or effect of methsuximide by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Tecovirimat is a weak inhibitor of CYP2C8 and CYP2C19. Monitor for adverse effects if coadministered with sensitive substrates of these enzymes.

              • triclabendazole

                triclabendazole will increase the level or effect of methsuximide by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. If plasma concentrations of the CYP2C19 substrates are elevated during triclabendazole, recheck plasma concentration of the CYP2C19 substrates after discontinuation of triclabendazole.

              Minor (26)

              • acetaminophen

                methsuximide decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

              • acetaminophen IV

                methsuximide decreases levels of acetaminophen IV by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

              • acetaminophen rectal

                methsuximide decreases levels of acetaminophen rectal by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

              • amobarbital

                methsuximide decreases effects of amobarbital by pharmacodynamic antagonism. Minor/Significance Unknown.

              • atracurium

                methsuximide decreases effects of atracurium by pharmacodynamic antagonism. Minor/Significance Unknown.

              • biotin

                methsuximide decreases levels of biotin by unspecified interaction mechanism. Minor/Significance Unknown. Biotin supplementation may be necessary.

              • butabarbital

                methsuximide decreases effects of butabarbital by pharmacodynamic antagonism. Minor/Significance Unknown.

              • butalbital

                methsuximide decreases effects of butalbital by pharmacodynamic antagonism. Minor/Significance Unknown.

              • cisatracurium

                methsuximide decreases effects of cisatracurium by pharmacodynamic antagonism. Minor/Significance Unknown.

              • cyanocobalamin

                methsuximide decreases levels of cyanocobalamin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

              • dexmethylphenidate

                dexmethylphenidate increases effects of methsuximide by decreasing metabolism. Minor/Significance Unknown.

              • ethotoin

                methsuximide increases effects of ethotoin by pharmacodynamic synergism. Minor/Significance Unknown.

              • fosphenytoin

                methsuximide increases effects of fosphenytoin by pharmacodynamic synergism. Minor/Significance Unknown.

              • levocarnitine

                methsuximide decreases levels of levocarnitine by unspecified interaction mechanism. Minor/Significance Unknown.

              • onabotulinumtoxinA

                methsuximide decreases effects of onabotulinumtoxinA by pharmacodynamic antagonism. Minor/Significance Unknown.

              • pancuronium

                methsuximide decreases effects of pancuronium by pharmacodynamic antagonism. Minor/Significance Unknown.

              • pentobarbital

                methsuximide decreases effects of pentobarbital by pharmacodynamic antagonism. Minor/Significance Unknown.

              • phenobarbital

                methsuximide decreases effects of phenobarbital by pharmacodynamic antagonism. Minor/Significance Unknown.

              • phenytoin

                methsuximide increases effects of phenytoin by pharmacodynamic synergism. Minor/Significance Unknown.

              • primidone

                methsuximide decreases effects of primidone by pharmacodynamic antagonism. Minor/Significance Unknown.

              • rapacuronium

                methsuximide decreases effects of rapacuronium by pharmacodynamic antagonism. Minor/Significance Unknown.

              • rocuronium

                methsuximide decreases effects of rocuronium by pharmacodynamic antagonism. Minor/Significance Unknown.

              • sage

                sage decreases effects of methsuximide by pharmacodynamic antagonism. Minor/Significance Unknown. Theoretical interaction; some species of sage may cause convulsions.

              • secobarbital

                methsuximide decreases effects of secobarbital by pharmacodynamic antagonism. Minor/Significance Unknown.

              • succinylcholine

                methsuximide decreases effects of succinylcholine by pharmacodynamic antagonism. Minor/Significance Unknown.

              • vecuronium

                methsuximide decreases effects of vecuronium by pharmacodynamic antagonism. Minor/Significance Unknown.

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              Adverse Effects

              Frequency Not Defined

              Common

              • Ataxia, dizziness, somnolence
              • Erythema
              • Abdominal pain, constipation, diarrhea, epigastric pain, loss of appetite, nausea, vomiting, weight loss
              • Hematuria, proteinuria

              Serious

              • Auditory hallucinations (rare), psychotic disorder (rare), suicidal behavior (rare)
              • Stevens-Johnson syndrome
              • Disorder of hematopoietic structure, leukopenia, monocytosis, pancytopenia
              • Systemic lupus erythematosus
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              Warnings

              Contraindications

              Hypersensitivity

              Cautions

              Do not discontinue rapidly

              Succinimides have been associated with blood dyscrasias

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              Pregnancy & Lactation

              Pregnancy Category: C

              Lactation: avoid during breastfeeding

              Pregnancy Categories

              A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

              B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

              C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

              D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

              X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

              NA: Information not available.

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              Pharmacology

              Mechanism of Action

              Succinimide; depresses motor cortex, increases convulsive stimuli threshold in CNS

              Pharmacokinetics

              Half-Life: 3 hr

              Time: 1-3 hr

              Concentration: 3-7 mcg/mL (dose-dependent)

              Therapeutic plasma concentration: 10-40 mcg/mL

              Metabolism: Liver

              Excretion: Urine

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              Administration

              Oral Administration

              May take with or without food

              Avoid abrupt discontinuation

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              Images

              BRAND FORM. UNIT PRICE PILL IMAGE
              Celontin oral
              -
              300 mg capsule

              Copyright © 2010 First DataBank, Inc.

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              Patient Handout

              Patient Education
              methsuximide oral

              METHSUXIMIDE - ORAL

              (meth-SUX-eh-mide)

              COMMON BRAND NAME(S): Celontin

              USES: This medication is used alone or with other medications to prevent and control a certain type of seizure (absence or petit mal seizure). It works by controlling the abnormal electrical activity in the brain that occurs during a seizure.

              HOW TO USE: Read the Medication Guide provided by your pharmacist before you start taking this medication and each time you get a refill. If you have any questions, ask your doctor or pharmacist.Take this medication by mouth with or without food, usually once or twice daily or as directed by your doctor.Dosage is based on your medical condition and response to treatment.It is very important to follow your doctor's dosing instructions exactly. Your doctor will start you on a low dose and slowly increase your dose. It may take several weeks or months to reach the best dose for you and to get the full benefit from this medication. Use this medication regularly in order to get the most benefit from it. To help you remember, take it at the same time(s) each day.Do not stop taking this medication without consulting your doctor. Some conditions may become worse when the drug is suddenly stopped. Your dose may need to be gradually decreased.Tell your doctor if your condition does not improve or if it worsens.

              SIDE EFFECTS: Drowsiness, dizziness, stomach/abdominal pain, loss of appetite, nausea, vomiting, weight loss, diarrhea, headache, or loss of coordination may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.A small number of people who take anticonvulsants for any condition (such as seizure, bipolar disorder, pain) may experience depression, suicidal thoughts/attempts, or other mental/mood problems. Tell your doctor right away if you or your family/caregiver notice any unusual/sudden changes in your mood, thoughts, or behavior including signs of depression, suicidal thoughts/attempts, thoughts about harming yourself.Tell your doctor right away if any of these rare but very serious side effects occur: signs of infection (such as fever, persistent sore throat), aching swollen joints, rash on nose and cheeks, severe tiredness, easy bruising/bleeding, rapid breathing.A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

              PRECAUTIONS: Before taking methsuximide, tell your doctor or pharmacist if you are allergic to it; or to ethosuximide; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: liver problems, kidney problems.This drug may make you dizzy or drowsy. Alcohol or marijuana (cannabis) can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Avoid alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.It is unknown if this medication passes into breast milk. Consult your doctor before breast-feeding.

              DRUG INTERACTIONS: The effects of some drugs can change if you take other drugs or herbal products at the same time. This can increase your risk for serious side effects or may cause your medications not to work correctly. These drug interactions are possible, but do not always occur. Your doctor or pharmacist can often prevent or manage interactions by changing how you use your medications or by close monitoring.To help your doctor and pharmacist give you the best care, be sure to tell your doctor and pharmacist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products) before starting treatment with this product. While using this product, do not start, stop, or change the dosage of any other medicines you are using without your doctor's approval.A product that may interact with this drug is: orlistat.Tell your doctor or pharmacist if you are taking other products that cause drowsiness, including alcohol, marijuana (cannabis), antihistamines (such as cetirizine, diphenhydramine), drugs for sleep or anxiety (such as alprazolam, diazepam, zolpidem), muscle relaxants, and opioid pain relievers (such as codeine).Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely.This document does not contain all possible interactions. Keep a list of all the products you use. Share this list with your doctor and pharmacist to lessen your risk for serious medication problems.

              OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: slow/shallow breathing, severe drowsiness, loss of consciousness.

              NOTES: Do not share this medication with others.Laboratory and/or medical tests (such as complete blood count, kidney/liver function) should be performed periodically to monitor your progress or check for side effects. Consult your doctor for more details.

              MISSED DOSE: It is important to take each dose at the scheduled time. If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

              STORAGE: Store at room temperature at 77 degrees F (25 degrees C) away from light and moisture. Brief storage between 59-86 degrees F (15-30 degrees C) is permitted. Do not store in the bathroom. Protect from heat sources such as a closed car or steam pipes. Do not use capsules that appear only partly full or in which the contents have melted. Keep all medicines away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.

              MEDICAL ALERT: Your condition can cause complications in a medical emergency. For information about enrolling in MedicAlert, call 1-888-633-4298 (US) or 1-800-668-1507 (Canada).

              Information last revised August 2021. Copyright(c) 2021 First Databank, Inc.

              IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.

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              Tier Description
              1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
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              Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.