Myokymia Medication

Updated: Oct 19, 2016
  • Author: Suying L Song, MD; Chief Editor: Nicholas Lorenzo, MD, MHA, CPE  more...
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Medication

Medication Summary

Phenytoin and carbamazepine have been proven to be effective in treating patients with generalized myokymia, specifically patients with continuous muscle fiber activity described by Isaacs syndrome. High therapeutic drug levels usually are required to reach satisfactory control of symptoms. EMG can objectively document the disappearance of myokymic discharges.

Other newer-generation anticonvulsant medications with mechanisms of action modulating sodium and potassium channels can also be tried with caution. Monitoring of potential adverse effects of phenytoin and carbamazepine and precautions for these drugs are no different from when they are used to treat epilepsy. Medications such as benzodiazepines have been tried with no consistent benefit.

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Antiepileptic agents

Class Summary

These agents prevent seizure recurrence and terminate clinical and electrical seizure activity.

Phenytoin (Dilantin)

Has promising results in patients with Isaacs syndrome. Relieves cramps and pain of involved muscles. EMG can document objective resolution of myokymic discharges. Mechanism of action possibly related to its effect on sodium channel.

Dosage adjusted according to blood level. Target level should be at high therapeutic range.

Carbamazepine (Tegretol)

Has promising results in patients with Isaacs syndrome. Relieves cramps and pain of involved muscles. EMG can document objective resolution of myokymic discharges. Mechanism of action possibly related to its effect on sodium channel.

Dosage adjusted according to blood level. Target level should be at high therapeutic range.

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