Prescription ·Strong evidence ·Reviewed May 2026
Prescription serotonin-norepinephrine reuptake inhibitor (SNRI) approved for major depressive disorder, generalized anxiety disorder, social anxiety disorder, and panic disorder. Exhibits dose-dependent neurotransmitter effects: primarily serotonergic at lower doses, with additional noradrenergic activity at higher doses. Dosage must be determined by your prescribing physician.
The bottom line
Evidence rating strong. Most-documented uses: depression symptom relief, generalized anxiety reduction, social anxiety improvement. 10 sources indexed (1998–2024), with 5 interaction records on file.
Core mechanism
Inhibits the reuptake of both serotonin (5-HT) and norepinephrine (NE) by blocking their respective transporters (SERT and NET). At lower doses (75 mg), serotonin reuptake inhibition predominates; norepinephrine reuptake inhibition becomes clinically significant at doses above 150 mg. Weak dopamine reuptake inhibition at very high doses.3,10
Take with food to reduce nausea. Swallow extended-release capsules whole; do not crush, chew, or dissolve. Taper gradually to minimize discontinuation symptoms.3
Nutrients this medication can lower over time, and what to replace.
Antidepressant-associated SIADH can increase renal free-water retention and dilute serum sodium, producing hyponatremia.
Venlafaxine is an SNRI that blocks serotonin reuptake, particularly at lower doses where its effect is predominantly serotonergic. Adding 5-HTP increases serotonin synthesis while venlafaxine prevents its clearance, creating significant serotonin syndrome risk.
Recommendation: Do not combine 5-HTP with venlafaxine. The serotonin syndrome risk is significant. Discontinue 5-HTP before starting venlafaxine therapy.
Combining venlafaxine with St. John's Wort creates a dangerous risk of serotonin syndrome. Multiple case reports have documented this interaction. St. John's Wort's serotonin reuptake inhibition adds to venlafaxine's, while its CYP induction may unpredictably alter venlafaxine and O-desmethylvenlafaxine levels.
Recommendation: Do not take St. John's Wort with venlafaxine. This is a well-documented dangerous combination. If you are currently using both, contact your prescriber immediately.
SAMe has antidepressant and monoamine-modulating activity. Venlafaxine increases serotonergic signaling, especially at lower and moderate doses, and also increases norepinephrine at higher doses. Adding SAMe may increase the risk of serotonin toxicity or mood activation.
Recommendation: Do not add SAMe to venlafaxine without prescriber approval. Stop the supplement and seek urgent care for clonus, high fever, severe agitation, confusion, seizure, or rapidly escalating manic symptoms.
L-Tryptophan is the upstream dietary precursor for serotonin, and venlafaxine blocks serotonin reuptake. Concentrated tryptophan supplements can add serotonergic substrate on top of venlafaxine's reuptake blockade, raising the risk of serotonin syndrome. Food sources of tryptophan are not the issue; high-dose supplements are.
Recommendation: Do not combine L-tryptophan supplements with venlafaxine. If you are using L-tryptophan for sleep or mood, stop it and ask your prescriber for a safer alternative. Watch for tremor, sweating, agitation, diarrhea, fever, or muscle jerking if exposure occurred.
MDMA releases large amounts of serotonin and norepinephrine through monoamine transporters, while venlafaxine blocks serotonin and norepinephrine reuptake. The combination can be unpredictable: venlafaxine may blunt desired MDMA effects, which can prompt redosing, while MDMA still drives hyperthermia, hypertension, seizures, and serotonin syndrome risk. Reported MDMA-associated serotonin syndrome cases commonly involve other serotonergic substances.
Recommendation: Do not use MDMA while taking venlafaxine. Do not try to overcome a blunted MDMA effect by taking more; that raises toxicity risk. If exposure occurs and you develop high fever, agitation, confusion, clonus, chest pain, or severe headache, seek emergency care.
Numbered references. Citations throughout the page link here.
Kamp CB, Petersen JJ, Faltermeier P et al.. The risks of adverse events with venlafaxine for adults with major depressive disorder: a systematic review of randomised clinical trials with meta-analysis and Trial Sequential Analysis. Epidemiology and psychiatric sciences. 2024
Lense XM, Hiemke C, Funk CSM et al.. Venlafaxine's therapeutic reference range in the treatment of depression revised: a systematic review and meta-analysis. Psychopharmacology. 2024
Dose-response meta-analysis found venlafaxine effective starting at 75 mg/day with maximum efficacy at approximately 150-225 mg/day; higher doses provided minimal additional benefit but increased side effects.
Aiyer R, Barkin RL, Bhatia A. Treatment of Neuropathic Pain with Venlafaxine: A Systematic Review. Pain medicine (Malden, Mass.). 2017
VanderWeide LA, Smith SM, Trinkley KE. A systematic review of the efficacy of venlafaxine for the treatment of fibromyalgia. Journal of clinical pharmacy and therapeutics. 2015
Rudolph RL, Entsuah R, Chitra R. A meta-analysis of the effects of venlafaxine on anxiety associated with depression. Journal of clinical psychopharmacology. 1998
Kirsch N, Pacheco LD, Hossain A et al.. Medicolegal Review: Perinatal Effexor Lawsuits and Legal Strategies Adverse to Prescribing Obstetric Providers. AJP reports. 2019
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