Venlafaxine: Difference between revisions

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{{MedTemplate

| generic = Venlafaxine

| brand = Effexor

| brand = Effexor XR, Effexor IR (discontinued in US, generic widely available)

| structure =

| classes = SNRI, Antidepressant

| classes = [[:Category:SNRIs|Serotonin-norepinephrine reuptake inhibitor (SNRI)]], [[:Category:Antidepressants|Antidepressant]], [[:Category:Anxiolytics|Anxiolytic]]

| ~~mechanism = Serotonin–norepinephrine reuptake inhibitor~~

| uses = <vote slug="major-depressive-disorder-use">Major depressive disorder (FDA)</vote>, <vote slug="generalized-anxiety-disorder-use">Generalized anxiety disorder (FDA)</vote>, <vote slug="social-anxiety-disorder-use">Social anxiety disorder (FDA)</vote>, <vote slug="panic-disorder-use">Panic disorder (FDA)</vote>, <vote slug="ptsd-use">Posttraumatic stress disorder (off-label)</vote>, <vote slug="neuropathic-pain-broad-use">Neuropathic pain (off-label)</vote>, <vote slug="menopausal-vasomotor-use">Menopausal vasomotor symptoms (off-label, evidence-supported)</vote>

| uses =

| starting_dose = XR 37.5 mg PO once daily for 4-7 days, then 75 mg/day; titrate by 75 mg every ≥4 days to clinical effect. IR 25-37.5 mg BID-TID

~~| starting_dose~~ =

| preparations = IR tablets 25, 37.5, 50, 75, 100 mg; XR capsules 37.5, 75, 150, 225 mg

~~| preparations~~ =

| fda_max = 225 mg/day outpatient (XR); 375 mg/day inpatient (IR divided TID); 75 mg/day in moderate hepatic impairment

~~| routes~~ =

| pill_id =

~~| onset~~ =

| routes = Oral

~~| duration~~ =

| onset = Antidepressant effect over 1-2 weeks; anxiolytic effect over 4-6 weeks

~~| halflife~~ =

| duration = 24 hours (XR); 12 hours (IR)

~~| bioavailability~~ =

| halflife = Venlafaxine 5 hours; desvenlafaxine active metabolite 11 hours<ref name="effexor-xr-label">FDA Prescribing Information, Effexor XR (venlafaxine extended-release), Wyeth/Pfizer, current revision. https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/020699s107lbl.pdf</ref>

| ~~pregnancy~~ =

| bioavailability = ~45%<ref name="effexor-xr-label" />

| ~~legal~~ =

| pregnancy = Observational signal for neonatal adaptation syndrome with late-pregnancy exposure; weigh against the risks of untreated maternal depression.{{citation needed}}

| ~~intro~~ =

| legal = [[USLegal:Prescription only|Rx-only]] in US. Carries the antidepressant '''Boxed Warning''' for suicidality in children, adolescents, and young adults<ref name="effexor-xr-label" />

| ~~pharmacokinetics~~ =

| mechanism = <vote slug="venlafaxine-mech-claim">Serotonin and norepinephrine reuptake inhibitor with predominantly serotonergic activity at lower doses (37.5-150 mg); the noradrenergic effect adds at higher doses (>150 mg) and the dual-mechanism advantage really emerges then. The active metabolite desvenlafaxine (separately marketed as Pristiq) contributes meaningfully to clinical effect.</vote> '''Severe discontinuation syndrome''' is the marquee adverse-effect feature: venlafaxine's short half-life produces intense flu-like symptoms, dizziness, electric-shock sensations ("brain zaps"), and emotional dysregulation on abrupt discontinuation, worse than most other SNRIs and SSRIs. Slow taper essential. Dose-dependent '''diastolic hypertension''' at higher doses; routine BP monitoring at dose escalation. CYP2D6 substrate; CYP2D6 oxidation produces the active metabolite desvenlafaxine. PharmGKB clinical annotations for venlafaxine apply (Level 2A).<ref name="pharmgkb-venlafaxine">PharmGKB: Venlafaxine pharmacogenomics annotations. https://www.pharmgkb.org/chemical/PA451866</ref> No formal CPIC guideline covers venlafaxine; the CPIC SSRI/CYP2D6 guideline (Hicks 2015) covers sertraline, citalopram, escitalopram, fluoxetine, fluvoxamine, and paroxetine and does not extend to SNRIs.

| ~~pharmacodynamics~~ =

| ~~indications =~~

~~| dosing~~ =

| ~~effects~~ =

| ~~contraindications~~ =

~~| interactions~~ =

| ~~pregnancy_details~~ =

~~| monitoring~~ =

| ~~counseling~~ =

| ~~anecdotes~~ =

| ~~seealso~~ =

| ~~references~~ =

}}

== References ==

[[Category:SNRIs]]

[[Category:Antidepressants]]

[[Category:Anxiolytics]]

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