Venlafaxine

Administration

  • Type: SNRI
  • Dosage Forms:
  • Routes of Administration: Oral
  • Common Trade Names: Effexor

Adult Dosing

  • Extended release: 37.5-225mg PO daily
  • Immediate release: 75-375mg PO daily in 2-3 divided doses

Pediatric Dosing

Safety/efficacy not established

Special Populations

  • Pregnancy Rating: C
  • Lactation risk: Infant risk cannot be ruled out
  • Renal dosing: decrease dose by 25-50%
  • Hepatic dosing: decrease dose by 25-50%

Contraindications

  • Allergy to class/drug
  • MAOI use concomitantly or within past 14 days

Toxicity[1]

  • Sodium channel blocking properties, similar to TCA toxicity and should be treated similarly:
    • Sodium bicarbonate for QRS prolongation
    • Benzodiazepines for seizures
  • QTc prolongation

Adverse Reactions

Serious

  • Seizure
  • Neuroleptic malignant syndrome, serotonin syndrome
  • GI bleed
  • Hepatitis
  • Hyponatremia
  • Exacerbation of depression, suicidality, mania

Common

  • Constipation, nausea, xerostomia, anorexia, weight loss
  • Dizziness, insomnia, somnolence, dream disorder, tremor, anxiety, blurred vision
  • Sweating
  • Hypertension
  • Sexual dysfunction

Pharmacology

  • Half-life: 5-11h
  • Metabolism: Hepatic, CYP2D6
  • Excretion: Mostly renal

Mechanism of Action

  • Inhibits serotonin, norepinephrine and dopamine reuptake

Comments

See Also

References

  1. Whyte IM et al. Relative toxicity of venlafaxine and selective serotonin reuptake inhibitors in overdose compared to tricyclic antidepressants. QJM: An International Journal of Medicine, Volume 96, Issue 5, 1 May 2003, Pages 369–374.

Authors:

Claire, Kevin Lu