NREMT Paramedic Practice

What effect do parasympatholytic drugs typically produce?

1. Increase in heart rate

2. Increased sweating

3. Constriction of bronchi

4. Increased digestive activity

The correct answer is: Increase in heart rate

Parasympatholytic drugs, also known as anticholinergics, primarily block the action of the neurotransmitter acetylcholine in the parasympathetic nervous system. This inhibition typically leads to an increase in heart rate as one of its primary effects. By counteracting the parasympathetic effects that usually slow the heart rate, these drugs can stimulate the heart to beat more rapidly, which is a crucial response in certain medical situations, such as bradycardia, where the heart rate is abnormally low. In contrast to this effect, the other options pertain to functions typically enhanced by the parasympathetic nervous system. For instance, increased sweating would be associated with sympathetic stimulation rather than parasympathetic action. Likewise, constriction of bronchi is a parasympathetic effect, which aims to promote airway resistance—not enhanced by parasympatholytic drugs. Finally, increased digestive activity is also a consequence of parasympathetic stimulation, which anticholinergics would inhibit, reducing gastrointestinal motility and secretion instead. Thus, the primary role of parasympatholytic drugs is to decrease parasympathetic effects such as these while promoting an increase in heart rate.