Tadalafil
side effects, nutrient depletions, herbal interactions and health notes:
Data provided by Applied Health
• Hepatic Impairment In clinical pharmacology studies, tadalafil exposure (AUC) in subjects with mild or moderate hepatic impairment (Child–Pugh Class A or B) was comparable to exposure in healthy subjects when a dose of 10 mg was administered. There are no available data for doses higher than 10 mg of tadalafil in patients with hepatic impairment. Insufficient data are available for subjects with severe hepatic impairment (Child–Pugh Class C). Therefore, for patients with mild or moderate hepatic impairment, the maximum dose should not exceed 10 mg, and use in patients with severe hepatic impairment is not recommended1
• Indications/Clinical Studies Tadalafil and vardenafil are indicated for erectile dysfunction of various etiologies. Both drugs were effective in generalized ED clinical studies and also in studies of special populations of men with diabetes and men post nerve-sparing radical prostatectomy. The ages of men in clinical studies ranged from early 20s to early 80s, with average age being mid-50s. There are no published head-to-head studies of either tadalafil or vardenafil with sildenafil. Most studies have compared the drugs to placebo. Many studies excluded sildenafil nonresponders (Abramowicz, 2003; Broda, 2003; Cialis Prescribing Information, 2003). In October 2003, results of a 4-week multicenter, double-blind study of 463 nonresponders to sildenafil were presented at the fall research meeting of the Sexual Medicine Society of North America showing statistical and clinical improvement over baseline in vardenafil users over placebo (Carson et al., 2003).2
• Both tadalafil and vardenafil are (like sildenafil) classified as potent and highly selective phosphodiesterase type 5 (PDE5) inhibitors. Inhibition of PDE5 prevents cyclic guanosine monophosphate (cGMP) from being degraded in penile tissue. When the enzyme is inhibited, relaxation of the smooth muscle in the corpus cavernosum occurs and leads to inflow of blood, potentiating erection. Both drugs require sexual stimulation for response (Palacioz, 2003; Thomson Micromedex, 2003).3
• Erectile dysfunction (ED) affects more than 30 million men in the United States, more than 150 million men worldwide, and accounts for half a million visits to health care providers annually (Sharlip, Jarow, & Rajfer, 2003). In August 2003, the FDA approved vardenafil (Levitra® by Bayer/GlaxoSmithKline), and on November 21, 2003, tadalafil (Cialis® by Lilly/ICOS) was approved. Both drugs have been available and in widespread use in Europe and Latin America for several months and now join sildenafil (Viagra® by Pfizer) as oral treatment options for ED in the United States.4
• Tadalafil is available in 10 mg and 20 mg tablets and should be taken orally 30 minutes to 1 hour before sexual activity. Effectiveness may onset in 15 to 30 minutes and can last as long as 36 hours for one dose, facilitating spontaneity. No more than one tablet should be taken in a single 24-hour period. Some clinical trials tested a daily dose of tadalafil (Cialis Prescribing Information, 2003; Porst et al., 2003)5
• Vardenafil is available in 2.5 mg, 5 mg, 10 mg, and 20 mg tablets. Recommended starting dose for most men is 10 mg taken orally approximately 1 hour before sexual activity. Effectiveness may onset in 30 to 60 minutes and usually lasts approximately 4 to 5 hours (similar to sildenafil). Maximum dosing frequency is once daily (Abramowicz, 2003; Keating & Scott, 2003; Palacioz, 2003)6
• Both drugs are well-tolerated and can be taken with or without food, although high-fat meals may delay response time. In mild renal and hepatic impairment, no dose adjustment is required. Dosages may need adjustment in moderate hepatic impairment or in patients receiving potent CYP3A4 inhibitors like ketoconazole, itraconazole, ritonavir, indinivir, and erythromycin (Keating & Scott, 2003; Thomson Micromedex, 2003).7
• There are no herbal considerations at this time8
References1 N/A
2 Abramowicz, M. (2003). Vardenafil (Levitra®) for erectile dysfunction. The Medical Letter, 45(1166), 77-78.
2 Broda, C. (2003). Levitra (vardenafil) and Viagra nonresponders. Pharmacist's Letter, 19(11), 12.
2 Carson, C., Hatzichristou, D., Carrier, S., Lording, D., Young, J., & Murdoch, M. (2003). Vardenafil exhibits efficacy in men with erectile dysfunction unresponsive to prior sildenafil therapy: Results of a phase III clinical trial – patient response with vardenafil in sildenafil nonresponders (PROVEN). Presented at the 5th Annual Fall Research Meeting of the Sexual Medicine Society of North America, October 11, 2003, Denver, CO.
3 Palacioz, K. (2003). New drug: Levitra (vardenafil). Pharmacist's Letter, 19(9), 190-901.
3 Thomson Micromedex. (2003). Tadalafil (Drugdex drug evaluations). Retrieved December 15, 2003, from www.drugdex.com
4 Sharlip, I., Jarow, J., & Rajfer, J. (2003). The diagnosis and treatment of erectile dysfunction. Symposium presented April 29, 2003, at American Urological Association 98th Annual Meeting, Chicago, IL.
5 Cialis Prescribing Information. (2003). Retrieved December 15, 2003, from www.cialisdruginformation.com
5 Porst, H., Padma-Nathan, H., Giullano, F., Anglin, G., Varanese, L., & Rosen, R. (2003). Efficacy of tadalafil for the treatment of erectile dysfunction at 24 and 36 hours after dosing: A randomized controlled trial. Urology, 62(1), 121-126.
6 Abramowicz, M. (2003). Vardenafil (Levitra®) for erectile dysfunction. The Medical Letter, 45(1166), 77-78.
6 Keating, G., & Scott, L. (2003). Vardenafil: A review of its use in erectile dysfunction. Drugs 2003, 63(23), 2673-2703.
6 Palacioz, K. (2003). New drug: Levitra (vardenafil). Pharmacist's Letter, 19(9), 190-901.
7 Keating, G., & Scott, L. (2003). Vardenafil: A review of its use in erectile dysfunction. Drugs 2003, 63(23), 2673-2703.
7 Thomson Micromedex. (2003). Tadalafil (Drugdex drug evaluations). Retrieved December 15, 2003, from www.drugdex.com
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Disclaimers
The information in Drug Watch is provided as a courtesy to NewsTarget readers by Applied Health Solutions in cooperation with Healthway Solutions. Although the information is presented with scientific references, we do not wish to imply that this represents a comprehensive list of considerations about any specific drug, herb or nutrient. Nor should this information be considered a substitute for the advice of your doctor, pharmacist, or other healthcare practitioner. Please read the disclaimer about the intentions and limitations of the information provided on these pages. It is important to tell your doctor and pharmacist about all other drugs and nutritional supplements that you are taking if they are recommending a new medication. Copyright © 2007 by Applied Health Solutions, Inc. All rights reserved.
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