The nurse is caring for a patient admitted with substance use disorder who recently injected heroin. During the physical assessment, which findings are likely to be present?

Choice A rationale Heroin is an opioid agonist that binds to mu-opioid receptors in the central nervous system, leading to profound depression of the brain's activity. This results in the classic triad of sedation or drowsiness, miosis which is constricted pupils, and respiratory depression. Slurred speech occurs due to the slowing of motor functions and neurological signaling. These symptoms represent the acute effects of the drug shortly after injection as the substance crosses the blood-brain barrier rapidly. Choice B rationale Anxiety and restlessness are typically associated with stimulant use or the early stages of opioid withdrawal rather than acute heroin intoxication. Paranoid delusions are more characteristic of substances like amphetamines, cocaine, or synthetic cathinones which increase dopamine levels in the mesolimbic pathway. While some users may feel agitated as the drug wears off, the immediate physical assessment after injection will show central nervous system depression rather than the hyper-arousal and psychosis suggested by these specific clinical findings. Choice C rationale Dilated pupils, muscle aching, and tachycardia are hallmark signs of opioid withdrawal syndrome, not acute heroin use. When an opioid-dependent person stops using, the noradrenergic system becomes overactive because it is no longer suppressed by the drug. This leads to physical distress, autonomic hyperactivity, and mydriasis. During an assessment of a patient who has recently injected heroin, you would expect the opposite findings, specifically pupillary constriction and a decrease in heart rate and overall physiological stimulation. Choice D rationale While euphoria is a common psychological effect of heroin due to the rapid release of dopamine, heightened sexuality and insomnia are more commonly linked to stimulants. Heroin typically acts as a central nervous system depressant that decreases libido and induces a state of somnolence or nodding off. Insomnia is more likely to occur during the withdrawal phase when the body is in a state of rebound hyperexcitability. The acute phase is characterized by a heavy, calm, and sedated physical state.