Methsuximide

Methsuximide is a prescription medicine used to treat absence (petit mal) seizures. Methsuximide belongs to a group of drugs called anticonvulsants. It works by decreasing abnormal electrical signaling in the brain.

Methsuximide is a prescription medicine used to treat absence (petit mal) seizures.  Symptoms include a short loss of awareness where the person may stare straight ahead and not respond to others.

Methsuximide may be found in some form under the following brand names:

• Celontin

Methsuximide can cause serious side effects. See "Drug Precautions" section.

The most common side effects of methsuximide include:

• drowsiness
• dizziness
• headache
• blurred vision
• nausea or vomiting
• constipation
• diarrhea
• weight loss
• problems with walking and coordination (unsteadiness)
• stomach pain
• loss of appetite

Tell your healthcare provider about any side effect that bothers you or that does not go away.

These are not all the possible side effects with methsuximide. For more information, ask your healthcare provider or pharmacist.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Tell your doctor about all the medications you take including prescription and non-prescription medications, vitamins, and herbal supplements. Especially tell your doctor if you take:

• other antiepileptic (anticonvulsant) drugs
• phenytoin
• phenobarbital

This is not a complete list of methsuximide drug interactions. Ask your doctor or pharmacist for more information.

Do not take methsuximide if you are allergic to succinimides (methsuximide or ethosuximide) or any of the other ingredients in it. 

Do not stop taking methsuximide without first talking to your healthcare provider. Stopping methsuximide suddenly can cause serious problems.

Methsuximide can cause serious side effects, including:

• Rare but serious blood problems that may be life-threatening. Call your healthcare provider right away if you have:
  • fever, swollen glands, or sore throat that come and go or do not go away
  • frequent infections or an infection that does not go away
  • easy bruising
  • red or purple spots on your body
  • bleeding gums or nose bleeds
  • severe fatigue or weakness

• Systematic Lupus Erythematosus. Call your healthcare provider right away if you have any of these symptoms:
  • joint pain and swelling
  • muscle pain
  • fatigue
  • low-grade fever
  • pain in the chest that is worse with breathing
  • unexplained skin rash

• Like other antiepileptic drugs, methsuximide may cause suicidal thoughts or actions in a very small number of people, about 1 in 500.

Call a healthcare provider right away if you have any of these symptoms, especially if they are new, worse, or worry you:

• thoughts about suicide or dying
• attempts to commit suicide
• new or worse depression
• new or worse anxiety
• feeling agitated or restless
• panic attacks
• trouble sleeping (insomnia)
• new or worse irritability
• acting aggressive, being angry, or violent
• acting on dangerous impulses
• an extreme increase in activity and talking (mania)
• other unusual changes in behavior or mood

Watch for early symptoms of suicidal thoughts and actions:

• Pay attention to any changes, especially sudden changes, in mood, behaviors, thoughts, or feelings.
• Keep all follow-up visits with your healthcare provider as scheduled.

Call your healthcare provider between visits as needed, especially if you are worried about symptoms. Suicidal thoughts or actions can be caused by things other than medicines. If you have suicidal thoughts or actions, your healthcare provider may check for other causes.

Medications can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of methsuximide, there are no specific foods that you must exclude from your diet when receiving this medication.

Before you take methsuximide, tell your healthcare provider if you:

• have or have had liver problems
• have or have had depression, mood problems or suicidal thoughts or behavior
• have any other medical conditions
• are pregnant or plan to become pregnant. It is not known if methsuximide can harm your unborn baby. Tell your healthcare provider right away if you become pregnant while taking methsuximide. You and your healthcare provider will decide if you should take methsuximide while you are pregnant.
• are breastfeeding or plan to breastfeed. It is not known if methsuximide can pass into breast milk. You and your healthcare provider should decide how you will feed your baby while you take methsuximide.

Tell your healthcare provider about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements. 

Tell your healthcare provider if you 

• are pregnant or plan to become pregnant. It is not known if methsuximide can harm your unborn baby. Tell your healthcare provider right away if you become pregnant while taking methsuximide. You and your healthcare provider will decide if you should take methsuximide while you are pregnant.

  • If you become pregnant while taking methsuximide, talk to your healthcare provider about registering with the North American Antiepileptic Drug (NAAED) Pregnancy Registry. The purpose of this registry is to collect information about the safety of antiepileptic drugs during pregnancy. You can enroll in this registry by calling 1-888-233-2334.

Tell your healthcare provider if you are breastfeeding or plan to breastfeed. It is not known if methsuximide can pass into breast milk. You and your healthcare provider should decide how you will feed your baby while you take methsuximide.

Take methsuximide exactly as prescribed. Your healthcare provider will tell you how much methsuximide to take.

• Your healthcare provider may change your dose. Do not change your dose of methsuximide without talking to your healthcare provider.
• If you take too much methsuximide, call your healthcare provider or your local Poison Control Center right away.

What you should avoid while taking methsuximide:

• Do not drink alcohol or take other medicines that make you sleepy or dizzy while taking methsuximide without first discussing this with your healthcare provider. Methsuximide taken with alcohol or medicines that cause sleepiness or dizziness may make your sleepiness or dizziness worse.
• Do not drive, operate heavy machinery, or do other dangerous activities until you know how methsuximide affects you. Methsuximide can slow your thinking and motor skills.

A suggested dosage schedule is 300 mg per day for the first week. If required, dosage may be increased thereafter at weekly intervals by 300 mg per day for the three weeks following to a daily dosage of 1.2 g.

Therapy with methsuximide must be individualized according to the response of each patient. The best dosage is the lowest amount of methsuximide that controls seizures so that side effects may be kept to a minimum.

If you take too much methsuximide, call your healthcare provider or your local Poison Control Center right away.

• Store methsuximide at room temperature, between 59°F to 86°F (15°C to 30°C).
• Keep methsuximide capsules in a dry place.
• Keep methsuximide out of the light.
• Protect methsuximide from heat.
• Do not use methsuximide capsules that if they do not look full or if the contents have melted.

Keep methsuximide and all medicines out of the reach of children.