Anticholinergics very often lead to dry mouth, because the saliva production is inhibited. In addition, the most common undesirable side effects include constipation, fatigue, impaired vision and urinary retention. Even in small doses, the effects of anticholinergics on the cardiovascular system play a role, for example, there may be tachycardia.
If anticholinergics are administered in very high doses, symptoms of poisoning may occur, which are summarized under the term anticholinergic syndrome. This describes a condition in which the parasympathetic nervous system has been largely shut down. Symptoms of the anticholinergic syndrome may include sleep disturbances, seizures, memory and cardiac arrhythmia, dilated pupils, increase in intraocular pressure (glaucoma attack), dry, hot skin, bowel and urinary retention.
Patients with such severe side effects on anticholinergics must be monitored in an intensive care unit. A possible antidote is the active ingredient physiostigmine, which cancels out the effect of the anticholinergics. First aid in atropine poisoning consists of the immediate administration of activated carbon, which prevents the atropine from being absorbed into the bloodstream in the gastrointestinal tract.
In addition, artificial respiration may be necessary, since from very high doses of anticholinergics a deadly respiratory paralysis can set in. In children, this can already occur at lower doses.