Negative myoclonus associated with tramadol use.

Area of Science:

• Neurology
• Pharmacology

Background:

• Negative myoclonus (NM) is characterized by shock-like, jerky involuntary movements resulting from sudden interruptions in muscle contraction.
• NM is typically associated with conditions such as epilepsy, metabolic encephalopathy, drug toxicity, and brain lesions.

Observation:

• A 55-year-old male presented with bilateral arm and neck NM after a 5-day course of tramadol (80-140 mg/day) for a common cold.
• The patient had no prior history of seizures, and magnetic resonance imaging revealed no acute brain lesions. Laboratory tests were also unremarkable.

Findings:

• The patient's NM resolved completely upon discontinuation of tramadol and initiation of oral clonazepam.
• This case suggests tramadol, even within therapeutic dosage ranges, can precipitate NM in individuals without pre-existing neurological or metabolic conditions.

Implications:

• This report underscores the potential for tramadol to induce NM, expanding the known adverse effects of this commonly used analgesic.
• Clinicians should consider tramadol-induced NM in the differential diagnosis of patients presenting with involuntary jerky movements, particularly when no other causative factors are evident.