Anti-spasmodic & Anti-cholinergic Anti-spasmodic medications work to relax tense, irritated muscles by blocking the action of acetylcholine, a chemical messenger responsible for muscle contractions. Examples include dicyclomine, hyoscyamine, and methscopolamine. Anti-cholinergic medications work by blocking the action of the neurotransmitter acetylcholine. Common examples include atropine, benztropine, and scopolamine.