Venlafaxine

Aka: Venlafaxine, Effexor, Venlafaxine Withdrawal

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II. Indications

  1. Major Depression including refractory cases
    1. Considered to be second-line agent
  2. Generalized Anxiety Disorder
  3. Obsessive Compulsive Disorder
  4. Post-Traumatic Stress Disorder

III. Mechanism

  1. Similar activity as Tricyclic Antidepressants
  2. Serotonin Norepinephrine Reuptake Inhibitor
    1. Selective Serotonin Reuptake Inhibitor (<150 mg/day)
    2. Both Serotonin and Norepinephrine Reuptake Inhibitor (>150 mg/day)
  3. Minimally inhibits Dopamine uptake

IV. Pharmacokinetics

  1. Venlafaxine Regular Release
    1. Half life: 5 to 11 hours

V. Safety

  1. Unknown safety in Lactation
  2. Pregnancy Category C

VI. Preparations: Venlafaxine

  1. Venlafaxine regular release (Effexor)
    1. Available as 25, 37.5, 75, 100 mg tablets (scored)
    2. Start: 25 mg PO tid
    3. Effective dose: 150-225 mg per day divided bid to tid
    4. Maximum dose: 375 mg per day
    5. Disadvantages: More adverse effects than Effexor XR
    6. Advantages: May be dosed once daily since metabolites offer similar duration to Effexor XR
  2. Venlafaxine extended release (Effexor XR)
    1. Available as 37.5, 75, 150 mg (capsules)
    2. Start: 37.5 to 75 mg orally daily
    3. Maximum: 225 mg orally daily
  3. Indications to decrease dose by 50% (or 25% if mild organ Impairment)
    1. Hepatic Impairment
    2. Renal Impairment or Hemodialysis

VII. Adverse Effects: Prominent Withdrawal symptoms

  1. See also Antidepressant Withdrawal
  2. Symptoms start 1-3 days after stopping medication (mild symptoms may have onset within hours of missed pill)
    1. Dizziness
    2. Irritability
    3. Insomnia
    4. Headache
    5. Gastrointestinal upset
    6. Ataxia or Vertigo
    7. Paresthesias (including shock-like Sensations)
    8. Tachycardia
    9. Fever
  3. Effexor taper schedule
    1. Reduce dose 25 mg/day every 5-7 days
    2. Taper to 25-50 mg/day before stopping
  4. Effexor XR taper schedule
    1. Reduce dose 37.5 to 75 mg per day every 7 days
    2. Taper to 37.5 mg/day before stopping
  5. Alternatives to tapering with Effexor
    1. Start Sertraline (Zoloft) 50 mg orally daily on stopping Effexor

VIII. Adverse Effects (more common with regular release Effexor)

  1. Anticholinergic (less than Tricyclic Antidepressants)
    1. Dizziness
    2. Somnolence
    3. Dry Mouth
  2. Nausea or Vomiting
    1. May be severe and limit dosing
    2. Start therapy at 25 mg per day
  3. Increased Blood Pressure
    1. Only seen with total daily doses 300 mg or higher
  4. Less Sexual Dysfunction than Prozac, Zoloft, Paxil
    1. Sexual Dysfunction in 10-15% of cases
    2. Similar to Luvox and Celexa
    3. See Antidepressant Induced Sexual Dysfunction
  5. More stimulating (anxiogenic) than sedating
    1. Agitation or Insomnia may occur
  6. Decreased appetite and Weight loss may occur
  7. Photosensitivity
  8. Suicidal Ideation and self harm (children)
  9. Ocular changes
    1. Increased Intraocular Pressure (Exercise caution in Glaucoma)
    2. Mydriasis

IX. Drug Interactions

  1. Minimal Cytochrome P450 interactions
  2. Metabolized by CYP2D6 and CYP3A4
  3. Avoid with MAO Inhibitors (including Linezolid)
  4. Exercise caution when combining with Cimetidine or Haloperidol
  5. Risk of Serotonin Syndrome (as with other SNRI and with SSRI)
    1. Monitor closely with Triptans

X. Resources

  1. Venlafaxine (DailyMed)
    1. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=55889b3d-74c9-4638-9a14-6a4ca3a99f7f

XI. References

  1. (2023) Med Lett Drugs Ther 62(1592): 25-32
  2. Olson (2020) Clinical Pharmacology, Medmaster Miami, p. 38-9
  3. Hamilton (2020) Tarascon Pocket Pharmacopoeia
  4. Mishler and Lovecchio (2017) Crit Dec Emerg Med 31(11): 15-20
  5. (1997) Am J Psych 154:1760 [PubMed]
  6. Sundberg (1995) Depression Primary Care, PGM, p. 45-57

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Related Studies

Cost: Medications

venlafaxine (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing)
VENLAFAXINE HCL 100 MG TABLET Generic $0.08 each
VENLAFAXINE HCL 25 MG TABLET Generic $0.06 each
VENLAFAXINE HCL 37.5 MG TABLET Generic $0.08 each
VENLAFAXINE HCL 50 MG TABLET Generic $0.07 each
VENLAFAXINE HCL 75 MG TABLET Generic $0.07 each
VENLAFAXINE HCL ER 150 MG CAP Generic $0.15 each
VENLAFAXINE HCL ER 150 MG TAB Generic $1.25 each
VENLAFAXINE HCL ER 225 MG TAB Generic $2.09 each
VENLAFAXINE HCL ER 37.5 MG CAP Generic $0.10 each
VENLAFAXINE HCL ER 37.5 MG TAB Generic $2.05 each
VENLAFAXINE HCL ER 75 MG CAP Generic $0.11 each
VENLAFAXINE HCL ER 75 MG TAB Generic $2.22 each
effexor (on 3/15/2022 at Medicaid.Gov Survey of pharmacy drug pricing)
EFFEXOR XR 150 MG CAPSULE Generic $0.15 each
EFFEXOR XR 37.5 MG CAPSULE Generic $0.10 each
EFFEXOR XR 75 MG CAPSULE Generic $0.11 each
FPNotebook does not benefit financially from showing this medication data or their pharmacy links. This information is provided only to help medical providers and their patients see relative costs. Insurance plans negotiate lower medication prices with suppliers. Prices shown here are out of pocket, non-negotiated rates. See Needy Meds for financial assistance information. GoodRx is another tool for finding lower drug prices.

Related Topics in Pharmacology

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