Myoclonus Associated with the Use of Gabapentin

Abstract

Summary:Purpose: To report on the occurrence of myoclonus in patients receiving gabapentin (GBP) for the treatment of epilepsy.Methods: Clinic charts of 104 consecutive patients started on GBP were reviewed. All patients were treated by the same physician, and most were specifically asked about the presence of myoclonus.Results: We found 13 cases of myoclonus. All patients had refractory epilepsy and were taking other antiepileptic drugs (AEDs). Six patients had a severe chronic static encephalopathy; five patients had no medical diagnosis other than seizures. Ten patients developed multifocal myoclonus. Three patients developed focal myoclonus, contralateral to their epileptic focus. Two patients had an exacerbation of preexistent myoclonus. An EEG performed during myoclonus on three patients showed no correlate. The myoclonus tended to persist as long as GBP was maintained, whereas discontinuance of GBP resulted in rapid cessation of the myoclonus. In all cases the myoclonus was subtle and did not significantly interfere with daily activities.Conclusions: GBP-associated myoclonus appears to be relatively frequent. It is usually mild and can easily be overlooked. Discontinuation of therapy is not necessary in most cases. Key Words: Gabapentin-Myoclonus-Anticonvulsants-Epilepsy-Movement disorders.Myoclonus occurs in a wide variety of clinical settings including epilepsy, after anoxic injury, metabolic derangement, viral infection, focal central nervous system (CNS) lesion, and as a side effect of medication. Gabapentin (GBP) is a drug recently introduced for the treatment of partial seizures. We observed a relatively high incidence of myoclonus associated with GBP therapy. PATIENTS AND METHODSClinic charts of 104 consecutive patients treated with GBP were reviewed. All patients were treated by one investigator (J.A.), and most were specifically asked about the presence of myoclonus during their regular office visits. All patients reporting myoclonus were interrogated and examined by the same physician (J.A.) and were extensively questioned regarding myoclonic symptoms before their use of GBP. The myoclonus was verified on physical examination in 10 cases and was obtained by history, because of its sporadic occurrence,

Safety and Tolerability of Antiepileptic Drug Treatment in Children with Epilepsy

“…Seizure aggravation as a consequence of prescribing an inappropriate AED for the particular seizure type or because of a paradoxical exacerbation of seizures should be followed by prompt review of treatment [8][9][10][11][12][13][14][15][16][17][18] (table II). Once identified, the most appropriate AED, starting with low doses, slow titration, adequate posology choice and individualization of the minimal effective maintenance doses, may greatly improve safety and tolerability.…”

Efficacy and tolerability of the new antiepileptic drugs II: Treatment of refractory epilepsy [RETIRED]

“…One case series and one case report identified worsening of myoclonic seizures in this population when they were treated with gabapentin. 9,10,76 Lamotrigine. One study with class I 77 and one with class II evidence 78 were identified.…”

“…5 This adverse event was reported as well in open trials. Review of adverse events in open trials and case reports revealed involuntary move- ments presenting as myoclonus, 9 choreoathetosis, [10][11][12] and incontinence of bowel and bladder. 13 No significant changes in serum levels of concomitant AEDs were identified in these studies, demonstrating the lack of interaction between gabapentin and other AEDs.…”

Aggravation of epilepsy by anti‐epileptic drugs

“…36 All had refractory epilepsy and six had an epileptic encephalopathy. The myoclonus was mild and may have been non-epileptic.…”