A nurse is teaching a 74-year-old client newly prescribed mi… | MyMerci
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Question
A nurse is teaching a 74-year-old client newly prescribed mirtazapine 7.5 mg PO at bedtime for depression with poor appetite and insomnia. Which statement indicates effective teaching?
1"I will need to follow a strict tyramine-free diet."
2"I should expect this medication to help me sleep and may improve my appetite."✓ Correct answer
3"I should stop the medication immediately if I gain any weight."
4"I will take this medication in the morning to avoid feeling drowsy at night."
Explanation
Correct (2): Mirtazapine is unique among antidepressants for its strong sedation and appetite stimulation at low doses (≤15 mg) due to potent H1 histamine and 5-HT2A/2C blockade. These properties are clinically exploited in older adults with comorbid depression, insomnia, and weight loss. (1) Incorrect — bedtime dosing is essential for the sedative benefit. (3) Tyramine restriction applies to MAOIs. (4) Weight gain is often a desired effect in this client and not a reason to stop.
In-depth explanation
Memory Tip Mirtazapine = "MORE sedation at LOWER dose" — paradoxical because higher doses recruit more noradrenergic activity. Clinical Practice Guide Useful niche: depressed elderly with anorexia and insomnia where SSRI weight loss/insomnia side effects would be harmful.
Clinical scenario
Scenario 74-year-old female with major depression, weight loss, and chronic insomnia. Provider prescribed mirtazapine 7.5 mg PO HS, chosen for its sedation and appetite stimulation at low dose.
Key concepts
Tetracyclic antidepressant — Mirtazapine's drug class; blocks alpha-2, 5-HT2A/2C, 5-HT3, and H1 receptors — producing sedation, appetite increase, and antiemetic effect.
Histamine H1 blockade — Mechanism of mirtazapine's sedation and appetite stimulation; most prominent at low doses before noradrenergic effects dominate.
Geriatric depression — Depression in adults ≥65 — often presents with somatic complaints, weight loss, insomnia, and cognitive slowing rather than overt sadness.