Venlafaxine hydrochloride
Venlafaxine hydrochloride (Effexor)
Venlafaxine hydrochloride
(ven-lah- FAX-een)
Pregnancy Category: C Effexor Effexor XR (Rx)

Classification: Antidepressant, miscellaneous

Action/Kinetics: Not related chemically to any of the currently available antidepressants. A potent inhibitor of the uptake of neuronal serotonin and norepinephrine in the CNS and a weak inhibitor of the uptake of dopamine. Has no anticholinergic, sedative, or orthostatic hypotensive effects. The major metabolite--O-desmethylvenlafaxine (ODV)--is active. The drug and metabolite are eliminated through the kidneys. t 1/2, venlafaxine: 5 hr; t 1/2, ODV: 11 hr. Time to reach steady state: 3-4 days. The half-life of the drug and metabolite are increased in clients with impaired liver or renal function. Food has no effect on the absorption of venlafaxine.

Uses: Treatment of depression. Treat generalized anxiety disorder (extended-release product).

Contraindications: Use with a MAO inhibitor or within 14 days of discontinuation of a MAO inhibitor. Use of alcohol. Lactation.

Special Concerns: Use with caution with impaired hepatic or renal function, in clients with a history of mania, and in those with diseases or conditions that could affect the hemodynamic responses or metabolism. Although it is possible for a geriatric client to be more sensitive, dosage adjustment is not necessary. Use for more than 4-6 weeks has not been evaluated. Safety and efficacy of the immediate release product have not been determined in children less than 18 years of age.

Side Effects: Side effects with an incidence of 0.1% or greater are listed. CNS: Anxiety, nervousness, insomnia, mania, hypomania, seizures, suicide attempts dizziness, somnolence, tremors, abnormal dreams, hypertonia, paresthesia, decreased libido, agitation, confusion, abnormal thinking, depersonalization, depression, twitching, migraine, emotional lability, trismus, vertigo, apathy, ataxia, circumoral paresthesia, CNS stimulation, euphoria, hallucinations, hostility, hyperesthesia, hyperkinesia, hypertonia, hypotonia, incoordination, increased libido, myoclonus, neuralgia, neuropathy, paranoid reaction, psychosis, psychotic depression, sleep disturbance, abnormal speech, stupor, torticollis. CV: Sustained increase in BP (hypertension), vasodilation, tachycardia, postural hypotension, angina pectoris, extrasystoles, hypotension, peripheral vascular disorder, syncope, thrombophlebitis, peripheral edema. GI: Anorexia, N&V;, dry mouth, constipation, diarrhea, dyspepsia, flatulence, dysphagia, eructation, colitis, edema of tongue, esophagitis, gastroenteritis, gastritis, glossitis, gingivitis, hemorrhoids, rectal hemorrhage melena, stomatitis, stomach ulcer, mouth ulceration. Body as a whole: Headache, asthenia, infection, chills, chest pain, trauma, yawn, weight loss, accidental injury, malaise, neck pain, enlarged abdomen, allergic reaction, cyst, facial edema, generalized edema, hangover effect, hernia, intentional injury, neck rigidity, moniliasis, substernal chest pain, pelvic pain, photosensitivity reaction. Respiratory: Bronchitis, dyspnea, asthma, chest congestion, epistaxis, hyperventilation, laryngismus, laryngitis, pneumonia, voice alteration. Dermatologic: Acne, alopecia, brittle nails, contact dermatitis, dry skin, herpes simplex, herpes zoster, maculopapular rash, urticaria. Hematologic: Ecchymosis, anemia, leukocytosis, leukopenia, lymphadenopathy, lymphocytosis, thrombocytopenia, thrombocythemia, abnormal WBCs. Endocrine: Hypothyroidism, hyperthyroidism, goiter. Musculoskeletal: Arthritis, arthrosis, bone pain, bone spurs, bursitis, joint disorder, myasthenia, tenosynovitis. Ophthalmic: Blurred vision, mydriasis, abnormal accommodation, abnormal vision, cataract, conjunctivitis, corneal lesion, diplopia, dry eyes, exophthalmos, eye pain, photophobia, subconjunctival hemorrhage, visual field defect. GU: Urinary retention, abnormal ejaculation, impotence, urinary frequency, impaired urination, disturbed orgasm, menstrual disorder, anorgasmia, dysuria, hematuria, metrorrhagia, vaginitis, amenorrhea, kidney calculus, cystitis, leukorrhea, menorrhagia, nocturia, bladder pain, breast pain, kidney pain, polyuria, prostatitis, pyelonephritis, pyuria, urinary incontinence, urinary urgency, enlarged uterine fibroids, uterine hemorrhage, vaginal hemorrhage vaginal moniliasis. Miscellaneous: Sweating, tinnitus, taste perversion, thirst, diabetes mellitus, alcohol intolerance, gout, hypoglycemic reaction, hemochromatosis, ear pain, otitis media.
Withdrawal syndrome: Anxiety, agitation, tremors, vertigo, headache, nausea, tachycardia, tinnitus, akathisia.

Laboratory Test Alterations: Alkaline phosphatase, creatinine, AST, ALT. Glycosuria, hyperglycemia, hyperlipemia, bilirubinemia, hyperuricemia, hypercholesterolemia, hypoglycemia, hypokalemia, hyperkalemia, hyperphosphatemia, hyponatremia, hypophosphatemia, hypoproteinemia, uremia, albuminuria.

Overdose Management: Symptoms: Extensions of side effects, especially somnolence. Other symptoms include prolongation of QTc, mild sinus tachycardia, and seizures. Treatment: General supportive measures; treat symptoms. Ensure an adequate airway, oxygenation, and ventilation. Monitor cardiac rhythm and VS. Activated charcoal, induction of emesis, or gastric lavage may be helpful.

Drug Interactions: Cimetidine / First-pass metabolism of venlafaxine Haloperidol / Serum levels MAO inhibitors / Serious and possibly fatal reaction, including hyperthermia, rigidity, myoclonus, autonomic instability with rapid changes in VS, extreme agitation, coma &herbal; St. John's wort / Sedation/hypnosis Trazodone / Possible "serotonin syndrome," including shivering, irritability, myoclonus, increased muscle tone, and altered consciousness

How Supplied: Capsule, Extended-Release: 37.5 mg, 75 mg, 150 mg; Tablet: 25 mg, 37.5 mg, 50 mg, 75 mg, 100 mg

Dosage
?Tablets Depression.
Adults, initial: 75 mg/day given in two or three divided doses. Depending on the response, the dose can be increased to 150-225 mg/day in divided doses. Make dosage increments up to 75 mg/day at intervals of 4 or more days. Severely depressed clients may require 375 mg/day in divided doses. Maintenance: Sufficient studies have not been undertaken to determine length of treatment.
?Capsules, Extended-Release Depression.
Adults, initial: 75 mg once daily. Dose can be increased by up to 75 mg no more often than every 4 days, to a maximum of 225 mg/day.
Generalized anxiety disorder.
Usual: 75-225 mg/day. To avoid overstimulation, some may need to start with 37.5 mg/day. Take on a daily basis not on an as-needed basis.