Which of the following is a commonly noted side effect of narcotics?

The presence of euphoria and drowsiness as commonly noted side effects of narcotics is well-documented in clinical practice and pharmacology. Narcotics, which are also known as opioids, work by binding to specific receptors in the brain that are responsible for pain relief; however, this interaction also influences mood and levels of alertness.

Euphoria occurs because these substances can stimulate the release of dopamine, a neurotransmitter that plays a crucial role in the brain's reward and pleasure centers. This effect is often perceived as feelings of intense happiness or well-being. Simultaneously, narcotics typically induce significant sedation or drowsiness due to their central nervous system depressant properties. This combination of effects is why euphoria and drowsiness are frequently cited as side effects, as they can alter a person’s emotional state and significantly impact their ability to function normally in daily activities.

In contrast, increased alertness and high energy levels are not associated with narcotics; these effects are more characteristic of stimulants. Frequent mood swings can occur with various medications and conditions, but they are not commonly recognized as a direct side effect of narcotics. Hence, the identification of euphoria and drowsiness as a side effect aligns with established medical knowledge regarding