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Pharmacologic class: Selective serotonin reuptake inhibitor

Therapeutic class: Antidepressant

Pregnancy risk category C

FDA Box Warning

• Drug may increase risk of suicidal thinking and behavior in children and adolescents with major depressive disorder and other psychiatric disorders. Risk must be balanced with clinical need, as depression itself increases suicide risk. With patient of any age, observe closely for clinical worsening, suicidality, and unusual behavior changes when therapy begins. Advise family and caregivers to observe patient closely and communicate with prescriber as needed.

• Drug isn't approved for use in children.


Potentiates serotonin and norepinephrine in CNS


Tablets (extended-release): 50 mg, 100 mg

Indications and dosages

Major depressive disorder

Adults: 50 mg P.O. daily

Dosage adjustment

• Severe renal impairment and end-stage renal disease

• Hepatic impairment (dosages above 100 mg daily not recommended)


• Hypersensitivity to drug, its components, or venlafaxine

• Within 14 days of an MAO inhibitor


Use cautiously in:

• renal impairment, hypertension, cardiovascular or cerebrovascular disease, lipid metabolism disorders, abnormal bleeding, interstitial lung disease, eosinophilic pneumonia, seizure disorder, bipolar disorder or family history of mania or hypomania, increased intraocular pressure, increased risk of angle-closure glaucoma

• concurrent use of selective serotonin reuptake inhibitors (SSRIs) or serotonin norepinephrine reuptake inhibitors (SNRIs) (use not recommended)

• pregnant or breastfeeding patients

• children (safety and efficacy not established).


• Make sure hypertension is controlled before therapy starts.

• Give tablets whole with or without food at same time each day. Don't break, dissolve, or divide tablets.

• Reduce dosage gradually when discontinuing drug.

Adverse reactions

CNS: dizziness, insomnia, somnolence, anxiety, fatigue, irritability, abnormal dreams, hypomania, mania, seizures

CV: hypertension

EENT: mydriasis, blurred vision, tinnitus

GI: nausea, vomiting, diarrhea, constipation, dry mouth

GU: male sexual function disorder

Hematologic: abnormal bleeding

Respiratory: interstitial lung disease, eosinophilic pneumonia

Skin: hyperhidrosis

Other: decreased appetite, weight loss


Drug-drug. Aspirin, NSAIDs, other drugs that affect coagulation: increased risk of bleeding

Drugs metabolized by CYP2D6 (such as despiramine): increased blood levels of these drugs

Drugs metabolized by CYP3A4 (such as midazolam): decreased blood levels of these drugs

MAO inhibitors, serotonergics (lithium, SNRIs, SSRIs, tricyclic antidepressants, triptans), tramadol: potentially life-threatening serotonin syndrome

Potent CYP3A4 inhibitors: increased desvenlafaxine blood level

Drug-diagnostic tests. Cholesterol, triglycerides: increased levels

Sodium: decreased level

Urine protein: transient elevation

Drug-food. Triptophan supplements: potentially life-threatening serotonin syndrome

Drug-herb. St. John's wort: potentially life-threatening serotonin syndrome

Patient monitoring

• Monitor patient's blood pressure regularly during therapy.

• Monitor cholesterol and triglyceride levels.

Monitor patient closely for clinical worsening, suicidality, and unusual behavior changes, especially during first few months of therapy and after dosage changes.

Monitor for progressive dyspnea, cough, or chest discomfort, which may signal serious lung disorders.

• Observe for signs and symptoms of hyponatremia (headache, poor concentration, memory impairment, confusion, weakness, and unsteadiness), especially in elderly patients.

After discontinuing drug, monitor for dysphoric mood, irritability, agitation, dizziness, paresthesia, anxiety, confusion, headache, lethargy insomnia, tinnitus, and seizures.

Patient teaching

• Instruct patient to take tablets whole with or without food at same time each day. Caution patient not to chew, break, crush, dissolve, or divide tablets.

• Tell patient that full drug effects may take several weeks; advise patient not to stop taking drug.

• Caution patient not to discontinue drug abruptly.

Advise patient's family or caregiver to monitor patient, especially for suicidality or new or worsening symptoms.

Instruct patient to immediately report unusual bruising or bleeding.

• Advise patient not to take over-the-counter drugs containing aspirin or NSAIDs without consulting prescriber.

• Instruct patient to avoid herbs (especially St. John's wort) unless prescriber approves.

• Caution patient to avoid hazardous activities until drug's effects on concentration and alertness are known.

• Tell patient that inert matrix tablet may appear in stool, but active drug has already been absorbed.

• Advise female patient to notify prescriber if she is pregnant, intends to become pregnant, or is breastfeeding.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, and herbs mentioned above.

McGraw-Hill Nurse's Drug Handbook, 7th Ed. Copyright © 2013 by The McGraw-Hill Companies, Inc. All rights reserved


(des-ven-la-fax-een) ,


(trade name),


(trade name)


Therapeutic: antidepressants
Pharmacologic: selective serotonin norepinephrine reuptake inhibitors
Pregnancy Category: C


Major depressive disorder.


Inhibits serotonin and norepinephrine reuptake in the CNS.

Therapeutic effects

Decrease in depressive symptomatology, with fewer relapses/recurrences.


Absorption: 80% absorbed following oral administration.
Distribution: Enters breast milk.
Metabolism and Excretion: 55% metabolized by the liver, 45% excreted unchanged in urine.
Half-life: 10 hr.

Time/action profile (blood levels)

POunknown7.5 hr24 hr


Contraindicated in: Hypersensitivity to venlafaxine or desvenlafaxine;Concurrent use of MAO inhibitors or MAO-like drugs (linezolid or methylene blue);Should not be used concurrently with venlafaxine.
Use Cautiously in: Untreated cerebrovascular or cardiovascular disease, including untreated hypertension (control BP before initiating therapy);Bipolar disorder (may activate mania/hypomania);History of ↑ intraocular pressure/angle-closure glaucoma;Renal impairment (consider modifications, dose should not exceed 50 mg/day, especially in moderate to severe renal impairment);History of seizures or neurologic impairment;Hepatic impairment (dose should not exceed 100 mg/day); Geriatric: Consider age-related ↓ in renal function, ↓ body mass, concurrent disease states, and medications; Obstetric / Lactation: Use only if maternal benefit outweighs fetal/infant risk; Pediatric: ↑ risk of suicidal thinking and behavior (suicidality) in children and adolescents with major depressive disorder and other psychiatric disorders. Observe closely for suicidality and behavior changes.

Adverse Reactions/Side Effects

Central nervous system

  • neuroleptic malignant syndrome (life-threatening)
  • seizures (life-threatening)
  • suicidal thoughts (life-threatening)
  • anxiety (most frequent)
  • dizziness (most frequent)
  • drowsiness (most frequent)
  • insomnia (most frequent)
  • headache
  • teeth grinding
  • vertigo

Ear, Eye, Nose, Throat

  • ↑ intraocular pressure
  • mydriasis


  • eosinophilic pneumonia
  • interstitial lung disease


  • hypertension


  • ↓ appetite (most frequent)
  • constipation (most frequent)
  • nausea (most frequent)


  • male sexual dysfunction (most frequent)


  • erythema multiforme (life-threatening)
  • stevens-johnson syndrome (life-threatening)
  • toxic epidermal necrolysis (life-threatening)
  • sweating (most frequent)

Fluid and Electrolyte

  • hyponatremia


  • ↑ risk of bleeding


  • hypercholesterolema
  • hyperlipidemia


  • serotonin syndrome (life-threatening)


Drug-Drug interaction

Concurrent use with MAO inhibitors may result in serious, potentially fatal reactions (wait at least 2 wk after stopping MAO inhibitor before initiating desvenlafaxine; wait at least 1 wk after stopping desvenlafaxine before starting an MAO inhibitor).Concurrent use with MAO-inhibitor like drugs, such as linezolid or methylene blue may ↑ risk of serotonin syndrome; concurrent use contraindicated; do not start therapy in patients receiving linezolid or methylene blue ; if linezolid or methylene blue need to be started in a patient receiving desvenlafaxine, immediately discontinue desvenlafaxine and monitor for signs/symptoms of serotonin syndrome for 2 wk or until 24 hr after last dose of linezolid or methylene blue, whichever comes first (may resume desvenlafaxine therapy 24 hr after last dose of linezolid or methylene blue)↑ risk of bleeding with other drugs that ↑ bleeding risk including anticoagulants, antithrombotics, platelet aggregation inhibitors, and NSAIDs.Use cautiously with other CNS-active drugs, including alcohol or sedative/hypnotics ; effects of combination are unknown.Drugs that affect serotonergic neurotransmitter systems, including tricyclic antidepressants, SNRIs, fentanyl, buspirone, tramadol, and triptans ↑ risk of serotonin syndromeKetoconazole may ↑ the effects of desvenlafaxine.


Oral (Adults) 50 mg once daily (range = 50–400 mg/day).

Renal Impairment

Oral (Adults) CCr 30–50 mL/min—50 mg once daily; CCr <30 mL/min—50 mg every other day.

Hepatic Impairment

Oral (Adults) Moderate-to-severe hepatic impairment—50 mg once daily (not to exceed 100 mg/day)

Availability (generic available)

Extended-release tablets: 50 mg, 100 mg Cost: Generic — All strengths $174.14 / 30

Nursing implications

Nursing assessment

  • Assess mental status and mood changes, especially during initial few months of therapy and during dose changes. Inform health care professional if patient demonstrates significant increase in signs of depression (depressed mood, loss of interest in usual activities, significant change in weight and/or appetite, insomnia or hypersomnia, psychomotor agitation or retardation, increased fatigue, feelings or guilt or worthlessness, slowed thinking or impaired concentration, suicide attempt or suicidal ideation).
  • Assess suicidal tendencies, especially in early therapy. Restrict amount of drug available to patient. Risk may be increased in children, adolescents, and adults ≤24 yr.
  • Monitor BP before and periodically during therapy. Sustained hypertension may be dose related; decrease dose or discontinue therapy if this occurs.
  • Monitor appetite and nutritional intake; weigh weekly. Report continued weight loss. Adjust diet as tolerated to support nutritional status.
  • Assess for serotonin syndrome (mental changes [agitation, hallucinations, coma], autonomic instability [tachycardia, labile BP, hyperthermia], neuromuscular aberations [hyperreflexia, incoordination], and/or GI symptoms [nausea, vomiting, diarrhea]), especially in patients taking other serotonergic drugs (SSRIs, SNRIs, triptans).
  • Assess patient for skin rash frequently during therapy. Discontinue at first sign of rash; may be life-threatening. Stevens-Johnson syndrome may develop. Treat symptomatically; may recur once treatment is stopped.
  • Lab Test Considerations: May cause ↑ fasting serum total cholesterol, LDL, cholesterol, and triglycerides.
    • May cause transient proteinuria, not usually associated with ↑ BUN or creatinine.
    • May cause hyponatremia.
    • May cause false-positive immunoassay screening tests for phencyclidine (PCP) and amphetamine.

Potential Nursing Diagnoses

Ineffective coping (Indications)
Risk for injury (Side Effects)


  • Do not confuse Pristiq with Prilosec.
  • Oral: Administer at the same time each day, with or without food. Swallow tablets whole; do not crush, break, chew, or dissolve.

Patient/Family Teaching

  • Instruct patient to take medication exactly as directed at the same time each day. Take missed doses as soon as possible unless almost time for next dose. Do not double doses or discontinue abruptly; gradually decrease before discontinuation to prevent dizziness, nausea, headache, irritability, insomnia, diarrhea, anxiety, fatigue, abnormal dreams, and hyperhidrosis.
  • Advise patient, family, and caregivers to look for suicidality, especially during early therapy or dose changes. Notify health care professional immediately if thoughts about suicide or dying, attempts to commit suicide, new or worse depression or anxiety, agitation or restlessness, panic attacks, insomnia, new or worse irritability, aggressiveness, acting on dangerous impulses, mania, or other changes in mood or behavior or if symptoms of serotonin syndrome occur.
  • May cause drowsiness or dizziness. Caution patient to avoid driving or other activities requiring alertness until response to the drug is known.
  • Caution patient to avoid taking alcohol or other CNS-depressant drugs during therapy and of increased risk of bleeding with concomitant use of NSAIDs, aspirin, or other drugs that affect coagulation or bleeding. Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult health care professional before taking other Rx, OTC, or herbal products.
  • Instruct patient to notify health care professional if signs of allergy (rash, hives, swelling, difficulty breathing) occur.
  • Instruct female patients to inform health care professional if pregnancy is planned or suspected or if breast feeding.
  • Emphasize the importance of follow-up exams to monitor progress.

Evaluation/Desired Outcomes

  • Increased sense of well-being.
  • Renewed interest in surroundings. Need for therapy should be periodically reassessed. Therapy is usually continued for several mo.
Drug Guide, © 2015 Farlex and Partners


A trademark for the drug desvenlafaxine.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
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Pharmaceutical Company Mylan NV (Nasdaq:MYL) reported on Monday the market availability of the generic version of the antidepressant drug PRISTIQ (Desvenlafaxine) in the US.
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Pristiq is an antidepressant that works by increasing the amounts of serotonin and norepinephrine, natural substances in the brain that help maintain mental balance.
The antidepressant desvenlafaxine (Pristiq) recently became available in the U.S.
Wyeth has applied to the Food and Drug Administration (FDA) for approval for Pristiq, a similar compound to the antidepressant Effexor, to treat menopause-related symptoms.
FDA ROUNDUP: Wyeth (Madison NJ) won approval to sell a drug called Pristiq to treat depression.