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vardenafil (Levitra, Staxyn)

Tradename: Levitra. New agent from Bayer. (2003) Indications: 1) erectile dysfunction 2) NO proof that vardenafil is better for patients with diabetes or after prostatectomy than sildenafil (Viagra) 3) may work when Viagra does not [3] Contraindications: 1) concurrent administration of nitrates [6] (or amyl nitrite) 2) intermediate-high risk of coronary artery disease 3) retinitis pigmentosa 4) history of non-arteric ischemic optic neuropathy Dosage: 1) 5-20 mg 25-60 minutes before intercourse 2) start 10 mg & adjust to need Tabs: 5, 10, 20 mg. (shelf-life 3 years) - Staxyn: orally disintegrating tablets Dosage adjustment in renal failure: - start 5 mg in patients with creatinine clearance < 30 mL/min Pharmacokinetics: 1) rapidly absorbed after oral administration 2) bioavailability is 15% 3) high-fat meal can reduce aborption 4) peak plasma levels in 30-120 minutes after oral dose 5) volume of distribution 120 liters 6) 95% bound to plasma proteins 7) metabolized by cyt P450 3A4 & to a lesser extent cyt P450 3A5 & cyt P450 2C9 8) elimination 1/2 life 4 hours Adverse effects: 1) see sildenafil (Viagra) 2) hopes than it may not cause 'blue vision' problem [2] Drug interactions: 1) concurrent administration of inhibitors of cyt P450 3A4 prolong 1/2 life of vardenafil a) potent inhibitors contraindicated - ritonavir, indinavir, ketoconazole, itraconazole b) erythromycin (diminish dose of vardenafil) c) grapefruit juice should be avoided 2) concurrent administration nitrates {6] or amyl nitrite* contraindicated 3) combined use with alpha-1 adrenergic antagonist increases risk of hypotension, especially orthostatic hypotension Laboratory: - vardenafil in blood - vardenafil in serum/plasma - vardenafil in urine Mechanism of action: 1) more selective than sildenafil (Viagra) for inhibition of phosphodiesterase-5. 2) inhibition of PDE-5 > 15 fold PDE-6, > 130 fold PDE-1 * both phosphodiesterase-5 inhibitors & nitric oxide converge on the same pathway; both increase cGMP. Phosphodiesterase-5 inhibitors inhibit hydrolysis of cGMP. Nitric oxide activates guanylate cyclase increasing synthesis of cGMP

Interactions

drug interactions drug adverse effects (more general classes)

Related

phosphodiesterase 5; cGMP-specific phosphodiesterase

General

phosphodiesterase-5 inhibitor

Properties

INHIBITS: phosphodiesterase-5 MISC-INFO: elimination route LIVER protein-binding 95%

Database Correlations

PUBCHEM correlations

References

  1. Prescriber's Letter 8(10):57 2001
  2. Prescriber's Letter 10(9):49 2003
  3. Prescriber's Letter 10(11):62 2003
  4. http://www.levitraguide.com
  5. Prescriber's Letter 18(8): 2011 COMMENTARY: New Vardenafil Formulation: Staxyn CHART: Phosphodiesterase 5 (PDE5) Inhibitor Interactions Detail-Document#: 270809 (subscription needed) http://www.prescribersletter.com
  6. Medical Knowledge Self Assessment Program (MKSAP) 19 American College of Physicians, Philadelphia 2022