A client is newly prescribed a medication that will block the effects of histamine for the treatment of a mental health disorder. The client asks, “What side effects should I anticipate with this new medication?” Which response by the nurse is accurate?

Choice A reason: Histamine blockade, as in antipsychotics like olanzapine, promotes sedation, not weight loss. Weight gain is common due to histamine’s role in appetite regulation via hypothalamic signaling. Weight loss is not a typical side effect, making this response inaccurate for histamine-blocking medications.

Choice B reason: Histamine receptor blockade, common in medications like quetiapine, reduces wakefulness by inhibiting histamine’s alerting effects in the cortex. This causes drowsiness, a frequent side effect in psychiatric treatments, aligning with the pharmacological mechanism and making this the correct response.

Choice C reason: Insomnia is not typical with histamine blockade, which promotes sedation. Histamine enhances alertness; blocking it, as in antihistaminic antipsychotics, induces sleepiness, not wakefulness. This response contradicts the neuropharmacological effect, making it incorrect for expected side effects.

Choice D reason: Blood pressure increase is unrelated to histamine blockade. Histamine affects wakefulness and appetite, not vascular tone directly. Antihistaminic drugs may cause orthostatic hypotension via other receptors, not hypertension, making this response inaccurate for histamine-blocking medication effects.

Choice A reason: Paroxetine, an SSRI, is first-line for GAD, enhancing serotonin in the amygdala and prefrontal cortex, reducing excessive worry. Its efficacy and tolerability, with minimal dependence risk, align with evidence-based guidelines for long-term anxiety management, making it the preferred choice.

Choice B reason: Imipramine, a tricyclic antidepressant, affects serotonin and norepinephrine but has significant anticholinergic side effects, reducing tolerability. It is not first-line for GAD due to slower onset and side effect profile compared to SSRIs, which better target anxiety’s neurobiological basis.

Choice C reason: Hydroxyzine, an antihistamine, reduces anxiety via histamine receptor blockade, causing sedation. It is used as needed, not for chronic GAD management. SSRIs, like paroxetine, offer sustained serotonin modulation, making hydroxyzine a less effective, non-first-line option for long-term treatment.

Choice D reason: Alprazolam, a benzodiazepine, enhances GABA activity, providing rapid anxiety relief but carries high dependence risk. It is not first-line for GAD, as SSRIs offer safer, long-term serotonin-based treatment, making alprazolam unsuitable for chronic management due to addiction potential.