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Stiripentol Side Effects

Medically reviewed by Last updated on Sep 5, 2022.

Applies to stiripentol: oral capsule, oral powder for suspension.

Serious side effects of Stiripentol

Along with its needed effects, stiripentol may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking stiripentol:

More common

  • Aggression
  • anxiety
  • chest tightness
  • cough producing mucus
  • dry mouth
  • fever
  • headache
  • irregular heartbeat
  • irritability
  • loss of strength or energy
  • muscle pain or weakness
  • nervousness
  • restlessness
  • shakiness and unsteady walk
  • sleepiness or unusual drowsiness
  • slurred speech
  • sore throat
  • stuffy or runny nose
  • trouble breathing
  • trouble sleeping
  • trouble speaking
  • unsteadiness, trembling, or other problems with muscle control or coordination
  • unusual tiredness or weakness

Other side effects of Stiripentol

Some side effects of stiripentol may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

  • Decreased appetite
  • increased watering of the mouth
  • nausea
  • vomiting
  • weight changes

For Healthcare Professionals

Applies to stiripentol: oral capsule, oral powder for reconstitution.


The more frequently occurring adverse reactions have included somnolence, decreased appetite, agitation, ataxia, decreased weight, hypotonia, nausea, tremor, dysarthria, and insomnia.[Ref]

Nervous system

During clinical trials, 1 patient discontinued therapy due to status epilepticus. A second patient discontinued therapy due to impaired balance, somnolence, and sialorrhea.[Ref]

Very common (10% or more): Somnolence (67%), ataxia (27%), hypotonia (18%), tremor (15%)

Rare (less than 0.1%): Status epilepticus, impaired balance[Ref]


Very common (10% or more): Nausea (15%)

Common (1% to 10%): Vomiting, salivary hypersecretion[Ref]


Very common (10% or more): Decreased appetite (46%), decreased weight (27%)

Common (1% to 10%): Increased weight[Ref]


Common (1% to 10%): Fatigue, pyrexia[Ref]


Very common (10% or more): Agitation (27%), insomnia (12%)

Common (1% to 10%): Aggression[Ref]


During clinical trials, a decrease in neutrophil count (normal to less than 1500 cells/mm3) occurred in 13% of stiripentol-treated patients (n=31) compared to no occurrences in placebo patients. Platelet counts dropped significantly (normal to less than 150,000/microliter) in 13% of stiripentol-treated patients compared to no occurrences in placebo patients.[Ref]

Very common (10% or more): Decrease in neutrophil count (13%), decrease in platelet count (13%)[Ref]


Frequency not reported: Rash, cutaneous allergy, urticaria, photosensitivity[Ref]


Frequency not reported: Diplopia[Ref]


Very common (10% or more): Dysarthria ((12%)


Common (1% to 10%): Bronchitis, nasopharyngitis

Frequently asked questions


1. "Product Information. Diacomit (stiripentol)." Biocodex USA (2018):

2. EMEA. European Medicines Agency "EPARs. European Union Public Assessment Reports." (2007):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.