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Serotonin antagonist & reuptake inhibitor (SARI)

Trazodone hydrochloride

Brand names: Molipaxin

Trazodone hydrochloride is a sedating antidepressant of the serotonin antagonist and reuptake inhibitor (SARI) class, used for depression, particularly where sleep disturbance or anxiety 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.

Clinical monograph

How it works

It inhibits serotonin reuptake and antagonises 5-HT2A receptors, with additional alpha-1-adrenergic and histamine H1 blockade that accounts for its marked sedative effect.

Prescribing in practice

  • Warn patients about the rare but urgent risk of priapism, which requires immediate medical attention to avoid permanent injury.
  • Postural hypotension and sedation are common, so dose is usually taken at night and titrated cautiously in older or frail patients.
  • Avoid combining with other serotonergic agents and monoamine oxidase inhibitors because of serotonin syndrome and QT-prolongation risk.

Monitoring

Monitor mood, suicidal ideation (especially early and after dose changes), blood pressure and, where cardiac risk exists, the QT interval.

Counselling the patient

  • Take the main dose at bedtime as it causes drowsiness, and do not drive until you know how it affects you.
  • Seek urgent care for a prolonged or painful erection.
  • Do not stop suddenly; the dose should be reduced gradually under guidance.

Evidence & guidelines

Antidepressant prescribing and the standard suicidality warning for under-25s are governed by NICE depression guidance and MHRA advice.

Reference: NICE NG222/NG97; 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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