Which opioid is associated with the effect of drowsiness?

Fentanyl is a powerful synthetic opioid that is known for its potent effects on the central nervous system, which can include drowsiness and sedation. As an opioid, fentanyl works by binding to the body's opioid receptors, which are located in the brain and are responsible for pain control, reward, and addictive behaviors. When fentanyl is consumed, it can produce significant sedative effects, leading to drowsiness, especially at higher doses.

In a clinical or law enforcement context, recognizing the sedation effects of opioids like fentanyl is crucial, as it can help officers understand the behavior and condition of individuals under the influence. Drowsiness can impair a person's ability to function normally, which can manifest in slowed reactions for those driving or operating machinery.

In contrast, the other substances listed have different effects. Ketamine is primarily a dissociative anesthetic and can induce a trance-like state rather than simple drowsiness. PCP (phencyclidine) can cause hallucinations and agitation, while cannabis may also induce relaxation or lethargy, but its primary effects do not include drowsiness at the same impactful level as fentanyl.