A review of 29 incidents involving 4-aminopyridine in non-target species reported to the ASPCA Animal Poison Control Center.

4-Aminopyridine (4-AP) is an avicide used in products that are approved by the Environmental Protection Agency (EPA) to control populations of various birds. Pharmaceutical 4-AP is also used in humans to treat neural and muscular dysfunctions associated with multiple sclerosis. Although strict restrictions for its use are in place, exposures to 4-AP bait by non-target species still occur. Twenty-nine exposures of 4-AP bait involving non-target species were identified and retrieved from the ASPCA Animal Poison Control Center medical record database. Canines were the most commonly exposed (86 %) species followed by felines (10 %). The highest frequency of exposures was reported from Colorado (22 %). Most commonly reported clinical signs in canines were tremors, hypersalivation, seizures, tachycardia, and ataxia. The onset time of signs ranged from 5 to 300 min with an average of 89 min. Clinical signs lasted from 15 to 84 h with an average of 37 h. Patient outcome was known in six cases; one dog died 4 h after the exposure and five made full recovery with supportive care. Treatment of five surviving patients included administration of activated charcoal, use of anticonvulsants and muscle relaxants like diazepam and methocarbamol, and intravenous fluids. Diagnosis of 4-AP toxicosis can be supported by testing the gastric contents of the exposed patient. Due to the rapid absorption, samples need to be collected and frozen/chilled promptly. For successful patient outcome, treatment must be implemented quickly after an exposure.