Anticholinergic chronotropic agents
What are Anticholinergic chronotropic agents?
Anticholinergic chronotropic agents are also known as muscarinic antagonists or parasympatholytic. All of them are competitive antagonists, and selectively block the effects of parasympathetic nerve activity. They block cardiac muscarinic receptors and cause tachycardia. They also have effect on other body systems such as inhibition of secretions, dilatation of pupils in the eyes, slowed gastrointestinal motility and relaxation of smooth muscle in lungs, urinary tract, etc.
Anticholinergic chronotropic agents are used to treat atrioventricular heart block and bradycardia.
Effects can include dry mouth and sore throat, resulting from the impaired secretion by exocrine glands. Another side effect is tachycardia, or a higher than usual heart rate, that occurs when anticholinergics interfere with receptors that typically slow the heart rate.
Examples include hydrocodone/homatropine (Tussigon, Hydromet, Hycodan), diphenoxylate/atropine (Lomotil), and hydrocodone polistirex/chlorpheniramine polistirex (Tussionex Pennkinetic, TussiCaps).
Acetylcholine has a negative chronotropic action, independent of cycle length. Acetylcholine also induces pacemaker shifts. Contrary to the pacemaker shifts caused by adrenaline, the new, acetylcholine-induced pacemaker center, has an identical site in all preparations.





