The clinical heterogeneity of drug-induced myoclonus: an illustrated review

Abstract

A wide variety of drugs can cause myoclonus. To illustrate this, we first discuss two personally observed cases, one presenting with generalized, but facial-predominant, myoclonus that was induced by amantadine; and the other presenting with propriospinal myoclonus triggered by an antibiotic. We then review the literature on drugs that may cause myoclonus, extracting the corresponding clinical phenotype and suggested underlying pathophysiology. The most frequently reported classes of drugs causing myoclonus include opiates, antidepressants, antipsychotics, and antibiotics. The distribution of myoclonus ranges from focal to generalized, even amongst patients using the same drug, which suggests various neuro-anatomical generators. Possible underlying pathophysiological alterations involve serotonin, dopamine, GABA, and glutamate-related processes at various levels of the neuraxis. The high number of cases of drug-induced myoclonus, together with their reported heterogeneous clinical characteristics, underscores the importance of considering drugs as a possible cause of myoclonus, regardless of its clinical characteristics.Electronic supplementary materialThe online version of this article (doi:10.1007/s00415-016-8357-z) contains supplementary material, which is available to authorized users.

Myoclonic Disorders

“…A minimum incidence of 0.2% of drug-induced myoclonus has been suggested in a French study [ 160 ]. Most frequently opioids, antidepressants, classic or atypical antipsychotics, antiepileptic drugs or antibiotics have been reported to underlie reversible medication-induced myoclonus [ 161 ]. Similarly, multiple agents can induce myoclonus in animal models of myoclonus.…”

“…Among antibiotic subgroups, beta-lactams, quinolones, sulfonamides or aminoglycosides can be found responsible most frequently. Furthermore, levodopa, dopamine agonists, anticonvulsant drugs, non-steroidal anti-inflammatory drugs, bismuth salts, lithium, amantadine, memantine, metoclopramide, calcium antagonists, corticosteroids, opioids, contrast media, chemotherapeutic drugs, propofol, as well as chronic intoxication with toluene, gasoline sniffing or substance withdrawal may be causally related [ 25 , 71 , 159 , 161 , 162 ]. With long-time antipsychotic use, a rare tardive myoclonus may occur.…”

Nasal pregabalin overdose and myclonus: a new way of misuse

“…Metabolic and toxic etiologies such as renal/hepatic failure, hyponatremia, hypoglycemia, hyperthyroidism, head trauma can cause myoclonus. Also many antiparkinsonian, antidepressant, anxiolytics, antiepileptic, analgesic, anesthetic drugs may induce myoclonus [6]. Pregabalin was reported to increase spikewave activity in a dose-dependent way in an animal model study with rats.…”

Amantadine Associated Myoclonus: Case Report and Review of the Literature

“…11 Commonly implicated medications include selective serotonin reuptake inhibitors (SSRIs), monoamine oxidase inhibitors, and antipsychotic agents. 1,2 There have been multiple case reports of levodopa-induced myoclonus as well. 12…”

“…1 There are multiple etiologies for myoclonus including metabolic derangements, medications, epilepsy, and neurodegeneration. 1,2 Myoclonus in Parkinson’s disease (PD) is an uncommon phenomenon. 3 When present, it is commonly related to metabolic disturbances or medications rather than PD itself.…”