Antidepressants: the delayed effect, early suicide risk, serotonin syndrome and the MAOI diet
- Safe practice
Antidepressants take weeks to work; the nurse watches mood and suicide risk early, spots serotonin syndrome and teaches the MAOI food rules.
What it is
Antidepressant classes include SSRIs, SNRIs, bupropion, trazodone, tricyclics (TCAs) and MAOIs. Some improvement may appear in the first week or two, but the full effect can take several weeks. While waiting, the person is still depressed, and in children, adolescents and young adults there is a warning about a higher suicide risk when the medicine starts or the dose changes. The nurse monitors mood and behaviour, recognises serotonin syndrome and, with MAOIs, the hypertensive crisis caused by tyramine, and teaches the person not to stop the medicine suddenly.
What it requires
- Baseline mood and suicide-risk assessment before the first dose, repeated during the first weeks and after dose changes.
- The full medicine list, including migraine medicines (triptans), cough medicines and street drugs that raise serotonin.
- For MAOIs: written food and medicine teaching (aged cheese, cured or smoked meats, alcoholic drinks, soy sauce, overripe fruit; decongestants).
- Blood pressure, heart rate and fall-risk checks, especially with TCAs and in older adults.
Components
- Monitoring of mood, sleep, behaviour and suicide risk.
- Recognition of the two emergencies: serotonin syndrome and the MAOI hypertensive crisis.
- Side-effect care: sexual effects, stomach upset, sleep change, dizziness, dry mouth, constipation.
- Teaching: timing of effect, adherence, no sudden stopping, interactions.
How it is applied (and why)
- Assess mood, sleep and suicide risk before starting and at each contact in the first weeks — energy may return before mood improves.
- Ask the person and family to report new or worse suicidal thoughts, agitation, panic, insomnia, irritability or signs of mania at once.
- Check all medicines and substances for others that raise serotonin before a new one is added — combinations trigger serotonin syndrome.
- If agitation, fever, sweating, tremor, clonus or fast heart rate appear after a start or dose rise, report urgently — serotonin syndrome can kill.
- With MAOIs, teach the tyramine food list and to avoid decongestants without the prescriber — tyramine can cause a hypertensive crisis.
- With TCAs, check lying and standing blood pressure and help older adults get up slowly — orthostatic hypotension causes falls.
- Offer fluids, fibre and mouth care for dry mouth and constipation, and ask openly about sexual effects — the prescriber can adjust or switch the medicine.
- Teach not to stop suddenly and to talk with the prescriber first — abrupt stopping causes withdrawal symptoms and relapse.
In nursing practice
- When an antidepressant starts, a very depressed person may regain the energy to act on suicidal thoughts before mood improves: keep close monitoring.
- Serotonin syndrome usually begins within 24 hours of a dose increase or a new combination; treatment starts with stopping the serotonergic medicines.
- In tricyclic overdose, call the rapid response team at once; several substances, including alcohol, are often taken together.
- Severe serotonin syndrome can look like neuroleptic malignant syndrome, which develops more slowly, over days.
Common mistakes
- Telling the person the medicine will work in a few days.
- Relaxing suicide precautions as soon as the medicine starts.
- Adding a medicine that raises serotonin without checking the list.
- Giving MAOI teaching without a written food list.
Test yourself
Think of the answer, then tap the question to see it.
Why is suicide risk watched closely in the first weeks of an antidepressant?
The full effect takes weeks, and there is a warning of higher suicide risk at the start or after dose changes, especially in children, adolescents and young adults.
Which signs suggest serotonin syndrome?
Mental change (agitation, confusion), autonomic signs (fever, sweating, fast heart rate, shivering, diarrhoea) and neuromuscular signs (tremor, hyperreflexia, clonus).
Why does a person taking an MAOI avoid aged cheese and cured meats?
They contain tyramine; with an MAOI it builds up and can cause a hypertensive crisis.
What should the person know about stopping an antidepressant?
Not to stop it suddenly or without the prescriber: stopping abruptly can cause withdrawal symptoms and the depression may return.
Connections
Educational content for students; it does not replace your institution's protocols, supervised clinical training or a prescriber's order. Dose-calculation examples use made-up numbers: they are educational, not a clinical order.
Sources: Nursing: Mental Health and Community Concepts, 7.4: Treatments for depression (Open RN, Wisconsin Technical College System (CC BY 4.0), LibreTexts, 2022); Nursing: Mental Health and Community Concepts, 7.5: Applying the nursing process to depressive disorders (Open RN, Wisconsin Technical College System (CC BY 4.0), LibreTexts, 2022); Nursing: Mental Health and Community Concepts, 6.3: Antidepressants (Open RN, Wisconsin Technical College System (CC BY 4.0), LibreTexts, 2022); Serotonin syndrome (Medical Encyclopedia) (MedlinePlus, U.S. National Library of Medicine, 2026).
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Representative model, for educational purposes only.