Subchronic Oral Toxicity of Pyridostigmine Bromide in Rats

This study evaluated the oral toxicity of pyridostigmine bromide in Sprague-Dawley rats when administered for 13 weeks by daily gavage. Groups of 10 rats/sex received doses of 0, 5, 15, 30, or 60 mg/kg/day. Toxicity was limited to exaggerated cholinergic stimulation at doses of 15 mg/kg/day or greater. Significant findings included tremors and inhibition of RBC acetylcholinesterase. Thus, 5 mg/kg/day of pyridostigmine bromide appears to be the no observed toxic effect level under the conditions of the present investigation.