Venlafaxine: prescribing and clinical use
Focused clinical detail for use alongside current product information, local policy and patient-specific assessment.
Venlafaxine: clinical details
Prescribing considerations
- Assess suicide and self-harm risk and monitor clinical worsening, particularly early in treatment and after treatment changes.
- Review cardiovascular history, blood pressure and factors predisposing to QT prolongation or arrhythmia.
- Consider seizure history, bipolar disorder or mania, angle-closure glaucoma risk, bleeding risk, diabetes and susceptibility to hyponatraemia.
- Renal or hepatic impairment reduces clearance and requires product-specific review.
- Consider overdose toxicity when assessing medicine quantity and concurrent alcohol or medicines.
- Plan discontinuation collaboratively because venlafaxine has a comparatively high propensity for withdrawal symptoms.
Contraindications and cautions
- Hypersensitivity to venlafaxine or a formulation excipient.
- Concurrent treatment with an irreversible monoamine oxidase inhibitor, including the required product-specific separation when switching.
Monitoring
- Mood, suicidal thoughts, agitation, aggression or emergent mania.
- Blood pressure before treatment and periodically thereafter; consider heart rate and cardiac assessment when clinically indicated.
- Serum sodium when symptoms or risk factors suggest hyponatraemia.
- Bleeding, glycaemic control in diabetes and ocular symptoms in susceptible patients.
- Withdrawal symptoms during reduction or discontinuation.
- During breastfeeding, infant feeding, alertness, gastrointestinal symptoms and weight gain.
Clinical pharmacology
Venlafaxine inhibits serotonin and noradrenaline reuptake and weakly inhibits dopamine reuptake. It is extensively metabolised, principally to active O-desmethylvenlafaxine; both contribute to clinical activity.
Formulation and product differences
- Immediate-release tablets and oral solutions have narrower licensed indications than selected prolonged-release products.
- Prolonged-release tablets and capsules provide slower absorption and must generally be swallowed whole.
- Oral solutions include a measuring device and are suitable for specified enteral tubes according to product instructions.
- Excipients vary: selected prolonged-release tablets contain lactose, while oral solutions contain maltitol and parabens; check the individual product information when sensitivity matters.
Venlafaxine preparations and strengths
Capsule
Route: Oral
Strengths: 37.5 mg, 75 mg, 150 mg
Modified-release capsule
Route: Oral
Strengths: 37.5 mg, 75 mg, 150 mg, 225 mg, 300 mg
Venlafaxine interactions
Check prescribed, non-prescription and herbal medicines before combining them with venlafaxine.
Monoamine oxidase inhibitors (MAOIs), including irreversible MAOIs, moclobemide, linezolid and methylene blue
Combinations can cause serious serotonin toxicity. Irreversible MAOIs are contraindicated, and switching requires carefully managed separation.
Other serotonergic medicines, including other antidepressants, triptans, lithium and some opioids
May increase the risk of serotonin syndrome and requires clinical review and monitoring.
St John’s wort and tryptophan supplements
May increase serotonergic adverse effects; do not add them without professional advice.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.