Medications and Drugs

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Brand Names: Celontin

Generic Name: methsuximide (Pronunciation: meth SUX i mide)

• What is methsuximide (Celontin)?
• What are the possible side effects of methsuximide (Celontin)?
• What is the most important information I should know about methsuximide (Celontin)?
• What should I discuss with my healthcare provider before taking methsuximide (Celontin)?
• How should I take methsuximide (Celontin)?
• What happens if I miss a dose (Celontin)?
• What happens if I overdose (Celontin)?
• What should I avoid while taking methsuximide (Celontin)?
• What other drugs will affect methsuximide (Celontin)?
• Where can I get more information?

What is methsuximide (Celontin)?

Methsuximide is an anti-epileptic medication, also called an anticonvulsant.

Methsuximide is used alone or in combination with other medications to treat absence seizures (also called "petit mal" seizures) in adults and children.

Methsuximide may also be used for other purposes not listed in this medication guide.

Celontin 150 mg

white/yellow, imprinted with 150mg, PD 537

Celontin 300 mg

white/yellow, imprinted with 300mg, PD 525

What are the possible side effects of methsuximide (Celontin)?

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have any new or worsening symptoms such as: mood or behavior changes, depression, anxiety, or if you feel agitated, hostile, restless, hyperactive (mentally or physically), or have thoughts about suicide or hurting yourself.

Call your doctor at once if you have a serious side effect such as:

• signs of infection such as fever, chills, sore throat, flu symptoms, easy bruising or bleeding (nosebleeds, bleeding gums), mouth sores, unusual weakness;
• signs of liver damage, such as nausea, stomach pain, low fever, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);
• joint pain or swelling with fever, swollen glands, muscle aches, chest pain;
• patchy skin color, red spots, or a butterfly-shaped skin rash over your cheeks and nose (worsens in sunlight);
• fever, sore throat, and headache with a severe blistering, peeling, and red skin rash; or
• worsening of seizures.

Less serious side effects may include:

• diarrhea, constipation;
• hiccups, vomiting, weight loss;
• dizziness, drowsiness, nervousness, confusion;
• blurred vision;
• sleep problems (insomnia); or
• loss of balance or coordination.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What is the most important information I should know about methsuximide (Celontin)?

Methsuximide can cause a decrease in many types of blood cells (white cells, red cells, platelets). Call your doctor at once if you have any unusual bleeding, weakness, or any signs of infection, even if these symptoms first occur after you have been using the medication for several months.

Methsuximide may also cause liver damage. Call your doctor if you have symptoms such as loss of appetite, stomach pain, or jaundice (yellowing of the skin or eyes).

You may have thoughts about suicide while taking this medication. Your doctor will need to check you at regular visits. Do not miss any scheduled appointments.

Call your doctor at once if you have any new or worsening symptoms such as: mood or behavior changes, depression, anxiety, or if you feel agitated, hostile, restless, hyperactive (mentally or physically), or have thoughts about suicide or hurting yourself.

Do not stop taking methsuximide without first talking to your doctor, even if you feel better. You may have increased seizures if you stop taking methsuximide suddenly. You will need to use less and less before you stop the medication completely.

Contact your doctor if your seizures get worse or you have them more often while taking methsuximide.

Carry an ID card or wear a medical alert bracelet stating that you are taking methsuximide, in case of emergency. Any doctor, dentist, or emergency medical care provider who treats you should know that you are taking a seizure medication.