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Selective Noradrenaline Reuptake Inhibitor (SNRI) — ADHD (Non-Stimulant) Pregnancy: Avoid — limited data; animal teratogenicity; neonatal withdrawal reported

Atomoxetine

Brand names: Strattera

Adult dose

Dose: Initial: 40 mg/day; increase after 3 days to 80 mg/day; max 100 mg/day
Route: Oral
Frequency: Once daily (morning) or divided twice daily
Max: 100 mg/day
Adult reference — see paediatric dose section

Paediatric dose

Dose: Initial: 0.5 mg/kg/day; increase after 7 days to 1.2 mg/kg/day target mg/kg
Route: Oral (capsules — do not open; irritant to eyes and mucous membranes)
Frequency: Once daily in the morning or divided into morning and late afternoon
Max: 1.8 mg/kg/day or 100 mg/day (whichever is lower); children ≤70 kg: max 1.8 mg/kg/day
BNFc: licensed from 6 years of age. CYP2D6 poor metabolisers — significantly higher plasma levels; reduce dose to 0.5 mg/kg/day and titrate slowly. Full therapeutic effect may take 2–4 weeks — distinguish from lack of response. Capsule contents are irritant — if accidentally opened, wash eyes immediately with water.

Dose adjustments

Renal

No dose adjustment required

Hepatic

Child-Pugh B: reduce dose by 50%; Child-Pugh C: reduce dose by 75%

Paediatric weight-based calculator

BNFc: licensed from 6 years of age. CYP2D6 poor metabolisers — significantly higher plasma levels; reduce dose to 0.5 mg/kg/day and titrate slowly. Full therapeutic effect may take 2–4 weeks — distinguish from lack of response. Capsule contents are irritant — if accidentally opened, wash eyes immediately with water.

Clinical pearls

  • FDA/MHRA black box warning: increased risk of suicidal ideation in children and adolescents — assess for suicidality at each visit during first months of treatment; involve parents in monitoring; not increased beyond background rate in adults
  • Advantages over methylphenidate: no abuse/diversion potential (non-scheduled), 24-hour coverage including mornings and evenings (no 'wearing off'), not contraindicated in tic disorders, can be used in comorbid anxiety
  • Hepatotoxicity: rare but serious — jaundice/dark urine should prompt immediate discontinuation and LFT check; advise families
  • CYP2D6 poor metabolisers (~7% Caucasians): check if patient is on CYP2D6 inhibitor (common antidepressants) — consider genotyping or empirical dose reduction
  • Onset of action: 2–4 weeks for ADHD symptoms vs immediate effect with stimulants — set appropriate expectations

Contraindications

  • Concurrent MAOIs (or within 2 weeks)
  • Narrow-angle glaucoma
  • Phaeochromocytoma
  • Severe cardiovascular disease
  • CYP2D6 poor metabolisers on potent CYP2D6 inhibitors (fluoxetine, paroxetine)

Side effects

  • Decreased appetite
  • Nausea and vomiting
  • Abdominal pain
  • Increased heart rate and blood pressure
  • Insomnia
  • Mood changes (irritability, aggression)
  • Suicidal ideation (MHRA/FDA black box warning)
  • Hepatotoxicity (rare — severe)
  • Urinary hesitancy/retention (noradrenergic)

Interactions

  • MAOIs — absolute contraindication (hypertensive crisis)
  • CYP2D6 inhibitors (fluoxetine, paroxetine) — dramatically increase atomoxetine levels — use with extreme caution; consider dose reduction
  • Salbutamol/sympathomimetics — additive cardiovascular effects
  • Antihypertensives — effects may be attenuated

Monitoring

  • Blood pressure and heart rate (baseline, after dose changes, then 6-monthly)
  • Height and weight (growth monitoring — 6-monthly)
  • Mood and suicidality assessment at each visit
  • LFTs if symptoms of hepatotoxicity
  • ADHD symptom rating scales (Conners, SNAP-IV)

Reference: BNF for Children; NICE NG87 (ADHD); MHRA Drug Safety Update 2019 (Atomoxetine Hepatotoxicity); Strattera SPC. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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