Tridione Side Effects Center

Last updated on RxList: 8/15/2022
Tridione Side Effects Center

What Is Tridione?

Tridione (trimethadione) is a seizure medication (antiepileptic) used to control absence ("petit mal") seizures.

What Are Side Effects of Tridione?

Common side effects of Tridione include:

Tridione may cause serious side effects including:

  • hives,
  • difficulty breathing,
  • swelling of your face, lips, tongue, or throat,
  • mood or behavior changes,
  • anxiety,
  • panic attacks,
  • trouble sleeping,
  • impulsiveness,
  • irritableness,
  • agitation,
  • hostility,
  • aggression,
  • restlessness,
  • hyperactivity (mentally or physically),
  • increased depression,
  • thoughts of suicide or self-harm,
  • vision problems,
  • droopy eyelids,
  • a skin rash (no matter how mild),
  • unusual muscle weakness,
  • trouble speaking or swallowing,
  • swelling in your feet or ankles,
  • fever,
  • chills,
  • flu-like symptoms,
  • swollen gums,
  • mouth sores,
  • skin sores,
  • rapid heart rate,
  • pale skin,
  • easy bruising,
  • unusual bleeding,
  • lightheadedness,
  • joint pain or swelling with fever,
  • swollen glands,
  • muscles aches,
  • chest pain,
  • butterfly-shaped skin rash on your cheeks,
  • little or no urinating,
  • painful or difficulty urination,
  • rapid weight gain,
  • nausea,
  • upper stomach pain,
  • itching,
  • tiredness,
  • loss of appetite,
  • dark urine,
  • clay-colored stools,
  • yellowing of the skin or eyes (jaundice),
  • sore throat,
  • burning in your eyes, and
  • skin pain followed by red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling

Get medical help right away, if you have any of the symptoms listed above.

Seek medical care or call 911 at once if you have the following serious side effects:

  • Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
  • Serious heart symptoms such as fast, irregular, or pounding heartbeats; fluttering in your chest; shortness of breath; and sudden dizziness, lightheartedness, or passing out;
  • Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors.

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

Dosage for Tridione

The usual adult dosage of Tridione is 0.9-2.4 grams daily in 3 or 4 equally divided doses (i.e., 300-600 mg 3 or 4 times daily).

What Drugs, Substances, or Supplements Interact with Tridione?

Tridione may interact with other drugs that cause drowsiness, including antidepressants, alcohol, antihistamines, pain relievers, anxiety medicines, other seizure medicines, and muscle relaxants. Tell your doctor all medications and supplements you use.

Tridione During Pregnancy or Breastfeeding

Tridione is known to be harmful to a fetus. Malformations of the face and head, heart, and nervous system have been reported. Tell your doctor if you are pregnant or could become pregnant during treatment. It is unknown if Tridion passes into breast milk and how it might affect a nursing infant. Consult your doctor before breastfeeding.

Additional Information

Our Tridione (trimethadione) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

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.


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Tridione Professional Information


The following side effects, some of them serious, have been associated with the use of TRIDIONE (trimethadione).


Nausea, vomiting, abdominal pain, gastric distress.


Drowsiness, fatigue, malaise, insomnia, vertigo, headache, paresthesias, precipitation of grand mal seizures, increased irritability, personality changes.

Drowsiness usually subsides with continued therapy. If it persists, a reduction in dosage is indicated.


Bleeding gums, epistaxis, retinal and petechial hemorrhages, vaginal bleeding, neutropenia, leukopenia, eosinophilia, thrombocytopenia, pancytopenia, agranulocytosis, hypoplastic anemia, and fatal aplastic anemia.


Acneiform or morbilliform skin rash that may progress to exfoliative dermatitis or to severe forms of erythema multiforme.


Hiccups, anorexia, weight loss, hair loss, changes in blood pressure, albuminuria, hemeralopia, photophobia, diplopia.

Fatal nephrosis has occurred.

Hepatitis has been reported rarely.

Lupus erythematosus, and lymphadenopathies simulating malignant lymphoma, have been reported.

Pruritus associated with lymphadenopathy and hepatosplenomegaly has occurred in hypersensitive individuals.

A myasthenia gravis-like syndrome has been reported.

Read the entire FDA prescribing information for Tridione (Trimethadione Tablets)


What Is Epilepsy? Symptoms, Causes, and Treatments See Slideshow

© Tridione Patient Information is supplied by Cerner Multum, Inc. and Tridione Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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