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SNRI Antidepressant Pregnancy: Avoid in pregnancy; neonatal adaptation syndrome; persistent pulmonary hypertension of newborn

Venlafaxine

Brand names: Efexor XL

Adult dose

Dose: 75-225 mg once daily (XL formulation)
Route: Oral
Frequency: Once daily with food
Max: 375 mg/day (severe depression under specialist care)
Start at 37.5-75 mg in elderly; XL formulation preferred for once-daily dosing and smoother plasma levels

Paediatric dose

Dose: Seek specialist opinion N/A/kg
Route: Oral
Frequency: Seek specialist opinion
Max: Seek specialist opinion
Seek specialist opinion

Dose adjustments

Renal

Reduce dose by 25-50% if eGFR 10-30; avoid if eGFR under 10

Hepatic

Reduce dose by 50% in moderate hepatic impairment; avoid in severe

Paediatric weight-based calculator

Seek specialist opinion

Clinical pearls

  • Hyponatraemia risk in elderly is a class effect of SNRIs and SSRIs — monitor sodium within 4 weeks of initiation
  • Blood pressure monitoring essential — venlafaxine raises BP in a dose-dependent manner; avoid in uncontrolled hypertension
  • Discontinuation syndrome is particularly severe with venlafaxine — always taper gradually; never stop abruptly (worse than most SSRIs)
  • MHRA 2012: Venlafaxine associated with cardiac conduction abnormalities at high doses — use with caution in cardiac disease
  • Effective for treatment-resistant depression when SSRIs have failed; dual action (serotonin + noradrenaline) provides broader efficacy

Contraindications

  • Concurrent MAOI use
  • Uncontrolled hypertension
  • High cardiac risk (QT prolongation)

Side effects

  • Nausea (very common initially)
  • Dizziness
  • Hypertension (dose-dependent)
  • Hyponatraemia (SIADH)
  • QT prolongation (at high doses)
  • Sexual dysfunction
  • Discontinuation syndrome (severe — dizziness, electric shock sensations)

Interactions

  • MAOIs (serotonin syndrome)
  • Tramadol / triptans (serotonin syndrome)
  • Warfarin (increased bleeding)
  • Drugs prolonging QT (additive risk)

Monitoring

  • Blood pressure (baseline and during treatment)
  • Sodium
  • ECG in patients with cardiac risk
  • Mood and suicide risk

Reference: BNFc; BNF 90; NICE CG90 (Depression); MHRA Drug Safety Update 2012; AGS Beers Criteria 2023. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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