4-aminopyridine (4-AP) is used in multiple sclerosis (MS) and spinal cord injury. An overdose can result in a spectrum of clinical findings.
Action: facilitates neural impulse conduction
Mechanism of action: potassium channel-blocking agent
Toxicity tends to be dose-dependent.
Clinical findings may include:
(1) agitation, disorientation or altered mental status
(2) cholinergic features (diaphoresis, other)
(3) nausea and vomiting
(4) dizziness
(5) paresthesias and/or tremor
(6) weakness
(7) seizures (tonic-clonic, other)
(8) dystonic, choreoathetoid-type movements
(9) encephalitis
(10) psychosis
(11) hypertension
(12) cardiac arrhythmias (supraventricular tachycardia, atrial fibrillation, bradycardia)
The diagnosis should be confirmed by measuring serum levels of 4-AP.