Neurotoxicity in rats following subchronic amiodarone treatment.

Rats were treated with amiodarone (20 mg/kg/day) up to 6 weeks and the neurotoxicity was assessed by determining changes in motor coordination, pain-threshold and rectal temperature every week during treatment. Body weight gain was decreased during amiodarone treatment and it was significant at and after 5 weeks. Food intake and water consumption were significantly reduced during treatment. After the first week of treatment with amiodarone, rats showed decreased ability to balance on horizontal rods. In the hot plate test (paw-lick), the amiodarone treated rats showed increased pain-thresholds throughout the treatment. Hypothermia was significant only at 6 weeks. These results show that amiodarone causes toxicity in rats and this model might be useful for further studies. Decreased motor-coordination, and increased pain-responding times may indicate development of peripheral neuropathy in addition to muscle weakness.