Medical Health Encyclopedia

Side Effects. Patients sometimes describe their state as "zombie-like." The most common and troublesome side effects are:

• Drowsiness.
• Memory problems.
• Problems with tasks requiring sustained performance.
• Problems with motor skills.
• Hyperactivity in some patients, particularly in children and the elderly.
• Depression in some adults.
• Some controversy has arisen over studies indicating that children taking phenobarbital score lower on intelligence tests, even for some months after going off the drug.

Primidone. Primidone (Mysoline) is converted in the body to phenobarbital, and so has the same benefits and adverse effects. It is reported that primidone is not as well tolerated as phenobarbital. Some authorities even believe that primidone has no advantage over the other drug.

Ethosuximide and Similar Drugs

Ethosuximide (Zarontin) is used for petit mal (absence) in children and adults when the patient has experienced no other type of seizures. Ethosuximide succeeds in abolishing petit mal seizures in 60% of patients and controls them in up to 90%. Use of this drug can cause stomach problems, dizziness, loss of coordination, and lethargy. In rare cases, it has caused severe and even fatal blood abnormalities. Periodic blood counts are recommended for patients taking this drug.

Text Continues Below

---

Methsuximide (Celontin), a drug similar to ethosuximide, may be suitable as an add-on treatment for intractable epilepsy in children without causing serious or permanent side effects.

Clonazepam and Similar Drugs

Clonazepam (Klonopin) is recommended for myoclonic and atonic seizures that cannot be controlled by other drugs and for Lennox-Gastaut (absence variant). It may be useful in newborns in whom other drugs are ineffective. Although clonazepam can prevent generalized or partial seizures, patients generally develop tolerance to the drug, and then seizures recur.