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SARI (Serotonin Antagonist and Reuptake Inhibitor)

Trazodone

Brand names: Molipaxin

Trazodone is a sedating antidepressant used for depression, particularly where anxiety or insomnia is prominent.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

Starting dose: 150 mg in divided doses daily. May be increased by 50 mg per day every three to four days. Maximum dose: 400 mg per day in divided doses ( 2 ). Trazodone hydrochloride tablets should be taken shortly after a meal or light snack ( 2 ). Tablets should be swallowed whole or broken in half along the score line, and should not be chewed or crushed ( 2 ). When discontinued, gradual dose reduction is recommended ( 2 ). 2.1 Dose Selection An initial dose of 150 mg/day in divided doses is suggested. The dosage should be initiated at a low-dose and increased gradually, noting the clinical response and any evidence of intolerance. Occurrence of drowsiness may require the administration …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2023-08-30. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Clinical monograph

How it works

It inhibits serotonin reuptake and antagonises certain serotonin and histamine receptors, the latter contributing to sedation.

Prescribing in practice

  • Its sedative effect makes it useful where sleep is disturbed; it is often taken at night.
  • Postural hypotension and, rarely, priapism (a urological emergency) can occur.
  • Risk of serotonin syndrome with other serotonergic drugs; taper to stop.

Monitoring

Review mood and suicidal ideation early; monitor for postural symptoms.

Counselling the patient

  • It is usually taken at night because it causes drowsiness.
  • Men should seek urgent help for a prolonged or painful erection.
  • Do not stop it suddenly.

Evidence & guidelines

An option for depression (NICE NG222), useful where sedation is desired.

Reference: NICE CG90 (Depression); Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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