A client who is receiving morphine sulfate for severe pain reports feeling nauseated and vomits. The nurse should recognize that this is an adverse effect of which of the following classifications of controlled substances?

Correct answer: d) Schedule IV

Rationale: Diazepam is a benzodiazepine that acts as a central nervous system depressant. It belongs to Schedule IV of controlled substances, which have a low potential for abuse and dependence compared to Schedule I, II, or III substances.

Incorrect choices:
a) Schedule I: Schedule I substances have no accepted medical use and a high potential for abuse and dependence. Examples include heroin, LSD, and ecstasy.
b) Schedule II: Schedule II substances have a high potential for abuse and dependence but have some accepted medical uses with severe restrictions. Examples include morphine, oxycodone, and cocaine.
c) Schedule III: Schedule III substances have a moderate potential for abuse and dependence but have accepted medical uses. Examples include codeine, ketamine, and anabolic steroids.

Correct answer: a) Opioids

Rationale: Opioids are controlled substances that act on opioid receptors to produce analgesia, euphoria, sedation, and respiratory depression. Nausea and vomiting are common adverse effects of opioids due to stimulation of the chemoreceptor trigger zone in the brain.

Incorrect choices:
b) Stimulants: Stimulants are controlled substances that increase alertness, energy, mood, and heart rate. Nausea and vomiting are not typical adverse effects of stimulants.
c) Depressants: Depressants are controlled substances that reduce anxiety, agitation, and insomnia. Nausea and vomiting are not typical adverse effects of depressants.
d) Hallucinogens: Hallucinogens are controlled substances that alter perception, cognition, mood, and behavior. Nausea and vomiting are not typical adverse effects of hallucinogens.