NaSSA Antidepressant

Mirtazapine (Elderly)

Brand names: Zispin SolTab, Mirtazapine

Mirtazapine is an antidepressant (noradrenergic and specific serotonergic) used for depression, often chosen where its sedative and appetite-stimulating effects are helpful.

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: 15 mg once daily; may increase up to maximum recommended dose of 45 mg once daily. ( 2.1 ) • Administer orally once daily, preferably in the evening prior to sleep. ( 2.1 ) • Reduce dose gradually when discontinuing mirtazapine tablets. ( 2.6 , 5.13 ) 2.1 Recommended Dosage The recommended starting dose of mirtazapine tablets is 15 mg once daily, administered orally, preferably in the evening prior to sleep. If patients do not have an adequate response to the initial 15 mg dose, increase the dose up to a maximum of 45 mg per day. Dose changes should not be made in intervals of less than 1 to 2 weeks to allow sufficient time for evaluation of response to a given dose [see …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2022-08-01. 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 blocks central α2-adrenoceptors and certain serotonin receptors, increasing noradrenergic and serotonergic transmission; antihistamine activity contributes to sedation.

Prescribing in practice

Sedation and increased appetite/weight gain are common; lower doses can be more sedating.
Rarely it causes blood dyscrasias — advise reporting sore throat, fever or other signs of infection.
Taper to stop.

Monitoring

Review mood and suicidal ideation early; monitor weight; check FBC if features of infection occur.

Counselling the patient

It is usually taken at night and can increase appetite.
Report sore throat, fever or feeling generally unwell.
Do not stop suddenly.

Evidence & guidelines

An option for depression per NICE NG222, useful where sedation or appetite stimulation is desired.

Reference: NICE NG222; BAP guidelines; 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).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways