What is a common side effect associated with opioids?

Opioids are known for their analgesic properties but also carry a range of potential side effects due to their action on the central nervous system. Bradycardia, which is a slower than normal heart rate, can occur as a result of opioid use. This happens because opioids can have a depressant effect on the heart rate through their interaction with specific receptors in the brain and body, particularly the mu-opioid receptors, which influence cardiovascular function.

As opioids can lower the overall metabolic rate and calm the central nervous system, the effect on the parasympathetic nervous system can lead to bradycardia as a response to their administration. While some may experience a variety of side effects, such as constipation or sedation, the slowing of heart rate is a distinct and notable reaction that can occur, especially in cases of higher doses or in sensitive populations.

In contrast, hypotonia refers to decreased muscle tone, which is not typically associated with opioid use in the same way as bradycardia. Increased energy is counter to the sedative effects opioids usually have, and tachycardia, or an increased heart rate, is generally not a common effect of opioids, as their depressant effects tend to lower heart rate rather than