An anticholinergic agent is a substance that blocks the neurotransmitter acetylcholine in the central and the peripheral nervous system. These agents inhibit parasympathetic nerve impulses by selectively blocking the binding of the neurotransmitter acetylcholine to its receptor in nerve cells. The nerve fibers of the parasympathetic system are responsible for the involuntary movement of smooth muscles present in the gastrointestinal tract, urinary tract, lungs, and many other parts of the body. Anticholinergics are divided into three categories in accordance with their specific targets in the central and peripheral nervous system: antimuscarinic agents, ganglionic blockers, and neuromuscular blockers.
Anticholinergic drugs are used to treat a variety of conditions:
Anticholinergics generally have antisialagogue effects (decreasing saliva production), and most produce some level of sedation, both being advantageous in surgical procedures.
When a significant amount of an anticholinergic is taken into the body, a toxic reaction known as acute anticholinergic syndrome may result. This may happen accidentally or intentionally as a consequence of recreational drug use. Anticholinergic drugs are usually considered the least enjoyable by many recreational drug users, possibly because the side effects are so unpleasant and that they do not induce euphoria. There have, however, been a few reported cases of users experiencing what they described as "euphoria" from the use of an anticholinergic drug. In terms of recreational use, these drugs are commonly referred to as deliriants. The risk of addiction is low in the anticholinergic class, and recreational use is uncommon.