Names and pronunciation
(var-den′a-fil) Levitra, Staxyn
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Drug reference
(var-den′a-fil) Levitra, Staxyn
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Func. class.: Erectile dysfunction agent
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Chem. class.: Phosphodiesterase type 5 inhibitor
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ACTION: Inhibits phosphodiesterase type 5 (PDE5), enhances erectile V function by increasing the amount of cGMP, which in turn causes smooth muscle relaxation and increased blood flow into the corpus cavernosum
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USES: Treatment of erectile dysfunction
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Unlabeled uses: Pulmonary arterial hyper tension, Raynaud’s disease
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CONTRAINDICATIONS: Hyper sensitivity, coadministration of α-blockers or nitrates, renal failure, congenital or acquired QT prolongation, women, preg nancy, children Precautions: Hepatic impairment, retinitis pigmentosa, anatomic penile deformities, sickle cell anemia, leuke mia, multiple myeloma, bleeding dis orders, active peptic ulceration, CV/ renal disease
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SIDE EFFECTS CNS: Headache, flushing, dizziness, insomnia EENT: Diminished vision, hearing loss GU: Abnormal ejaculation, priapism GI: Nausea MISC: Flulike symptoms
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INTERACTIONS • Do not use with nitrates because of unsafe decrease in B/P, which could re- sult in MI or stroke • Serious dysrhythmias: class IA/III antiarrhythmics, clarithromycin, droperi- dol, procainamide, quiNIDine, quino- lones; do not use concurrently Increase: hypotension—α-blockers, pro tease inhibitors, metoprolol, NIFEdipine, alcohol, amLODIPine, angiotensin II recep tor blockers; do not use concurrently Increase: vardenafil levels—erythromy cin, azole antifungals (ketoconazole, itraconazole), cimetidine Drug/Food Decrease: absorption—high-fat meal Increase: vardenafil level—grapefruit juice; avoid concurrent use Drug/Lab Test Increase: CK
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DOSAGE AND ROUTES Levitra • Adult: PO 10 mg taken 1 hr before sex ual activity; dose may be reduced to 5 mg or increased to max 20 mg; max dosing fre quency once daily; orally disintegrating tab 10 mg 60 min before sexual activity; do not use with potent CYP3A4 inhibitors • Geriatric >65 yr: PO 5 mg initially, ti trated as needed/tolerated Hepatic dose • Adult: PO (Child-Pugh B) 5 mg, max 10 mg/day Concomitant medications • Ritonavir, max 2.5 mg q72hr; for indinavir, ketoconazole 400 mg/day and itraconazole 400 mg/day, max 2.5 mg/day; for ketocon- azole 200 mg/day, itraconazole 200 mg/day and erythromycin max 5 mg/day Staxyn • Adult: PO 10 mg 1 hr before sexual activity, max 10 mg/24 hr
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Available forms: Tabs 2.5, 5, 10, 20 mg; orally disintegrating tab 10 mg
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Administer: • Approximately 1 hr before sexual ac tivity; do not use more than once daily; orally disintegrating tabs are not inter- changeable with film-coated tabs • Without regard to food; avoid taking with high-fat meal • Oral disintegrating tab: place on tongue immediately after opening blister pack, allow to dissolve, do not use water
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Assess: • B/P, including orthostatic; vasodilator properties • Erectile dysfunction and cause before treatment • Any severe loss of vision while taking this or similar products; products should not be used • Use of organic nitrates, which should not be used with this product • Pregnancy/breastfeeding: not used in women
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CLINICAL CONSIDERATIONS
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Patient and caregiver information: • That product does not protect against STDs, including HIV • That product absorption is reduced with high-fat meal • That product should not be used with nitrates in any form; to inform physician of all medications being taken • That product has no effect in the ab sence of sexual stimulation; that patient should seek immediate medical atten tion if erections last >4 hr • To notify prescriber immediately and stop taking product if vision loss occurs • To take 1 hr before sexual activity and only once per day • To notify prescriber of all OTC, pre scription, and herbal products taken
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PHARMACOKINETICS Rapidly absorbed, bioavailability 15%, protein binding 95%, metabolized by liver by CYP3A4, distribution semen, ter minal half-life 4-5 hr, onset 20 min, peak 1⁄2-11⁄2 hr, duration <5 hr, reduced absorption with high-fat meal, primarily excreted in feces (91%-95%)
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• Adult: PO 10 mg taken 1 hr before sex ual activity; dose may be reduced to 5 mg or increased to max 20 mg; max dosing fre quency once daily; orally disintegrating tab 10 mg 60 min before sexual activity; do not use with potent CYP3A4 inhibitors
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• Geriatric >65 yr: PO 5 mg initially, ti trated as needed/tolerated Hepatic dose
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• Adult: PO (Child-Pugh B) 5 mg, max 10 mg/day Concomitant medications
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• Ritonavir, max 2.5 mg q72hr; for indinavir, ketoconazole 400 mg/day and itraconazole 400 mg/day, max 2.5 mg/day; for ketocon- azole 200 mg/day, itraconazole 200 mg/day and erythromycin max 5 mg/day Staxyn
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• Adult: PO 10 mg 1 hr before sexual activity, max 10 mg/24 hr
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