Anticholinergics Administered as Pharmacologic Premedication.

    


    The muscarinic antagonists compete with neurally released
acetylcholine (ACh) for access to muscarinic cholinoceptors and block ACh’s effects. The results are faster heart rate, sedation, and dry mouth. With the exception of the quaternary ammonium compounds that do not readily cross the blood-brain barrier and have few actions on the CNS, there is no significant specificity of action among these
drugs; they block all muscarinic effects with equal efficacy,
although there are some quantitative differences in
effect.

    Addition of muscarinic antagonists is less important with modern inhaled anesthetics. Preoperative use of these drugs continues in some pediatric and otorhinolaryngologic cases or when fiberoptic intubation is planned.