 [ Symptoms ] contraction of the jaw tightening of the skin cannot walk and confined to bed [ Disease ] if overdose is suspected contact your local poison control center or emergency room immediately us residents should call the us national poison hotline at 1 800 222 1222 canada residents should call a provincial poison control center symptoms of overdose may include slow breathing slow heartbeat muscle stiffnesstwitching hot dry skin widened pupils seizure loss of consciousness