Names and pronunciation
(ven-la-fax′een) Effexor XR
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Drug reference
(ven-la-fax′een) Effexor XR
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Func. class.: Antidepressant—SNRI
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Chem. class.: SNRI
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ACTION: Potent inhibitor of neuronal serotonin and norepinephrine uptake, weak inhibitor of dopamine; no muscarinic, histaminergic, or α-adrenergic receptors in vitro
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USES: Prevention/treatment of major depression; depression at the end of life; long-term treatment of general anxiety disorder, panic disorder, social anxiety disorder (Effexor XR only)
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Unlabeled uses: Vasomotor symptoms in menopause, andropause, fibromyalgia
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CONTRAINDICATIONS: Hyper sensitivity, MAOIs Precautions: Pregnancy, breastfeeding, geriatric patients, mania, hypertension, seizure disorder, recent MI, cardiac/renal/ hepatic disease, eosinophilic pneumonia, desvenlafaxine hypersensitivity, bipolar disorder, interstitial lung disease, glaucoma
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Black Box Warning: Children, suicidal ideation Black Box Warning: Mental status: mood, sensorium, affect, increase in psychiatric symptoms, depression, panic; assess for suicidal ideation in children/ adolescents and in early treatment • Vital signs: B/P lying, standing; pulse q4hr; if systolic B/P drops 20 mm Hg, hold product, notify prescriber; take VS q4hr in patients with CV disease • Bleeding: GI, ecchymosis, epistaxis, he- matomas, petechiae, hemorrhage • Blood studies: CBC, differential, leuko cytes, cardiac enzymes if patient is re ceiving long-term therapy • Hepatic studies: AST, ALT, bilirubin • Weight weekly; weight loss or gain; ap petite may increase; peripheral edema may occur; monitor cholesterol • Withdrawal symptoms: flulike symptoms, headache, nervousness, agitation, nausea, vomiting, muscle pain, weakness; not usual unless product is discontinued abruptly • Serotonin syndrome, neuroleptic malignant syndrome: increased heart rate, shivering, sweating, dilated pupils, tremors, high B/P, hyperthermia, head- ache, confusion; if these occur, stop prod- uct, give serotonin antagonist if needed; usually worse if given with linezolid, methylene blue, tryptophan • Assistance with ambulation during be ginning therapy because drowsiness, diz ziness occur • Beers: use with caution in older adults; may exacerbate or cause syndrome of inappropriate antidiuretic hormone se cretion (SIADH) • Pregnancy/breastfeeding: use only if benefits outweigh fetal risk; use in late 3rd trimester has resulted in neonatal complications; do not breastfeed, ex- creted in breast milk Black Box Warning: That worsening of symptoms, suicidal thoughts/behaviors may occur in children or young adults; discuss with family members • To avoid alcohol ingestion • Not to discontinue medication abruptly after long-term use; may cause nausea, headache, malaise; taper over 14 days • To wear sunscreen or large hat be cause photosensitivity occurs • To avoid pregnancy or breastfeeding; birth defects have occurred when used in the 3rd trimester • To monitor B/P for new hypertension or if patient has history of hypertension • Serotonin syndrome, neuroleptic malignant syndrome: to report immedi- ately shivering, sweating, tremors, fever, dilated pupils • To take as prescribed, contents of capsule may be sprinkled on applesauce if unable to swallow whole
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SIDE EFFECTS CNS: Emotional lability, dizziness, weak ness, headache, hallucinations, insomnia, anxiety, suicidal ideation in children/ado- lescents, seizures, neuroleptic malignant syndrome–like reaction, anxiety, abnor mal dreams, paresthesia CV: Hypertension, chest pain, tachycar- dia, change in QTc interval, increased cholesterol, extrasystoles, syncope EENT: Abnormal vision, taste, ear pain GI: Dysphagia, eructation, nausea, anorexia, dry mouth, colitis, gastritis, gingivitis, constipation, stomatitis, stom ach and mouth ulceration, abdominal pain, vomiting, weight loss GU: Anorgasmia, abnormal ejaculation, urinary frequency, decreased libido, impotence, menstrual changes, impaired urination INTEG: Ecchymosis, dry skin, photosen sitivity, sweating, Stevens-Johnson syn- drome; angioedema (ext rel) META: Peripheral edema, weight loss
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INTERACTIONS Increase: Hyperthermia, rigidity, rapid fluctuations of vital signs, mental sta- tus changes, neuroleptic malignant syndrome: MAOIs Increase: bleeding risk—salicylates, NSAIDs, platelet inhibitors, anticoagulants Increase: venlafaxine effect—cimetidine Increase: CNS depression—alcohol, opioids, antihistamines, sedative/ hypnotics Increase: levels of cloZAPine, desipra mine, haloperidol, warfarin Increase: serotonin syndrome—lithium, sibutramine, SUMAtriptan, traZODone, traMADol, SSRIs, serotonin receptor ago- nist, linezolid, methylene blue, trypto- phan Decrease: effect of indinavir Decrease: venlafaxine effect—cyprohep tadine Drug/Herb • Increase: serotonin syndrome: St. John’s wort, tryptophan Increase: CNS depression—chamomile, hops, kava, valerian Drug/Lab Test Increase: alk phos, bilirubin, AST, ALT, BUN, creatinine, serum cholesterol, CPK, LDH False positive: amphetamines, phency clidine
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TREATMENT OF OVERDOSE: ECG monitoring; lavage; administer anticonvulsant; may require whole-bowel irrigation for ext rel product HIGH ALERT
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DOSAGE AND ROUTES Major Depression • Adult: PO 75 mg/day in 2-3 divided doses; taken with food, may be increased to 150 mg/day; if needed, may be further in creased to 225 mg/day; increments of 75 mg/day at intervals of ≥4 days; some hospi talized patients may require up to 375 mg/ day in 3 divided doses; EXT REL 37.5-75 mg PO daily, max 225 mg/day; give XR daily Anxiety disorders • Adult: PO 75 mg/day or 37.5 mg/day × 4-7 days initially, max 225 mg/day Social anxiety disorder (social phobia) • Adult: PO 75 mg/day, may start at 37.5 mg/day × 4-7 days, then 75 mg/day Panic disorder V • Adult: PO 37.5 mg/day × 7 days, titrate in increments of up to 75 mg/day at intervals of ≥7 days to max 225 mg/day if needed Renal dose • Adult: PO CCr 10-70 mL/min, reduce dose by 25%-50%; CCr <10 mL/min, re- duce dose by 50% Hepatic dose • Adult: PO moderate impairment, 50% of dose Hot flashes (unlabeled) • Adult (male, prostate cancer): PO 12.5 mg bid × 4 wk; females 37.5-75 mg/day
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Available forms: Tabs scored 25, 37.5, 50, 75, 100 mg; ext rel cap (Effexor XR) 37.5, 75, 150 mg, 225 mg
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Administer: • Once daily, AM or PM with food, milk for GI symptoms; do not crush, chew caps; caps can be opened and contents sprin kled on applesauce, given with full glass of water, use immediately • Sugarless gum, hard candy, frequent sips of water for dry mouth • Avoid use with CNS depressants • Missed dose should not be made up by doubling, take next scheduled dose at usual time • Give in small amounts because of suicide potential, especially at beginning of therapy • Store in tight container at room tem perature; do not freeze
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Assess:
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Evaluate: • Therapeutic response: decreased de pression, anxiety; increased well-being
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CLINICAL CONSIDERATIONS
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Patient and caregiver information: • To notify prescriber of rash, hives, al lergic reactions, bleeding • To use with caution when driving, per forming other activities requiring alert ness because of drowsiness, dizziness, blurred vision
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PHARMACOKINETICS Well absorbed; extensively metabolized in liver by CYP2D6 to active metabolite, some are poor metabolizers ; 87% of product recovered in urine; 27% protein binding; half-life 5, 11 hr (active metabolite), respectively, onset up to 14 days, peak up to 4 wk
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• Adult: PO 75 mg/day in 2-3 divided doses; taken with food, may be increased to 150 mg/day; if needed, may be further in creased to 225 mg/day; increments of 75 mg/day at intervals of ≥4 days; some hospi talized patients may require up to 375 mg/ day in 3 divided doses; EXT REL 37.5-75 mg PO daily, max 225 mg/day; give XR daily Anxiety disorders
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• Adult: PO 75 mg/day or 37.5 mg/day × 4-7 days initially, max 225 mg/day Social anxiety disorder (social phobia)
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• Adult: PO 75 mg/day, may start at 37.5 mg/day × 4-7 days, then 75 mg/day Panic disorder V
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• Adult: PO 37.5 mg/day × 7 days, titrate in increments of up to 75 mg/day at intervals of ≥7 days to max 225 mg/day if needed Renal dose
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• Adult: PO CCr 10-70 mL/min, reduce dose by 25%-50%; CCr <10 mL/min, re- duce dose by 50% Hepatic dose
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• Adult: PO moderate impairment, 50% of dose Hot flashes (unlabeled)
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• Adult (male, prostate cancer): PO 12.5 mg bid × 4 wk; females 37.5-75 mg/day
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