MSD Manual

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Causes of Seizures

Causes of Seizures



High fever


Viral encephalitis

Metabolic disorders

High blood levels of sugar (hyperglycemia) or sodium

Low blood levels of sugar (hypoglycemia), calcium, magnesium, or sodium

Other disorders

Kidney failure or liver failure, which can lead to dysfunction of the brain (encephalopathy)

Vitamin B6 deficiency (in newborns)

Inadequate oxygen supply to the brain

Near suffocation

Structural damage to the brain

Brain tumor (noncancerous or cancerous)

Intracranial hemorrhage (bleeding within the skull)


Abnormalities present or occurring at birth, including genetic disorders

Hereditary metabolic disorders, such as Tay-Sachs disease or phenylketonuria

Fluid accumulation in the brain (cerebral edema)

Prescription drugs*

Buspirone (used to treat anxiety disorders)


*Chlorpromazine (used to treat schizophrenia)

Ciprofloxacin (an antibiotic)

Chloroquine (used to treat malaria)

Clozapine (usually used to treat schizophrenia)

Cyclosporine (used to prevent and treat rejection of organ transplants)

Imipenem (an antibiotic)

*Indomethacin (used to relieve pain and reduce inflammation)

*Meperidine (used to relieve pain)


Theophylline (used to treat asthma and other airway disorders)

Tricyclic antidepressants

Recreational drugs

Cocaine (overdose)

Withdrawal of a drug after heavy use

General anesthetics (used during surgery)

Sedatives, including sleep aids

Exposure to toxins


* Various drugs can cause seizures if too much is taken. In some people, certain drugs can make seizures more likely to occur by making nerve cells in the brain easier to stimulate. These drugs are said to lower the seizure threshold.

Phenytoin, used to treat seizure disorders, can cause seizures if too much is taken.