(tadalafil, Eli Lilly)
A phosphodiesterase type 5 PDE-5) inhibitor for erectile dysfunction (ED), the third oral ED therapy approved. Viagra (sildenafil), approved in 1998, and Levitra (vardenafil), approved in August, also are PDE-5 inhibitors.
* Recommended Dosage: 10 mg before anticipated sexual activity, increasing to 20 mg or decreasing to 5 mg depending on effectiveness and tolerability. Taken only one time per day for most patients, given that Cialis' effects lasted for up to 36 hours in trials. (Lower doses for men with moderate and severe renal insufficiency, or with mild or moderate hepatic impairment.) No more than 10 mg per 72 hours when taken with potent CYP3A4 inhibitors like ketoconazole.
* Special Considerations: Contraindicated in patients on nitrates and those on any [alpha]-blocker, except for 0.4 mg of Flomax (tamsulosin) daily. Not recommended for men who have had a stroke or MI in the past 6 months, or men with significant hypotension, uncontrolled hypertension, unstable angina, severe liver impairment, or retinitis pigmentosa. The most common side effects in trials were headache, upset stomach, backache, and muscle aches. A few patients reported abnormal vision.
* Comment: In 22 studies of up to 24 weeks in over 4,000 patients aged 27-87 years, including men with diabetes or radical prostatectomy, Cialis "improved patients ability to achieve and maintain a penile erection," the Food and Drug Administration said in a statement. In studies, sexual activity improved in some patients within 30 minutes; other studies showed improvements in erectile function for up to 36 hours, according to the FDA. Physicians should consider duration of action when matching drug therapy to a patient's sexual activity pattern, said Dr. Harin Padma-Nathan of the University of Southern California, Los Angeles. In some European studies, the effect lasted for up to 60 hours.
Myalgia and back pain are probably related to the drug's inhibitory effect on PDE11, which is also found in cardiac myosites, Dr. Padma-Nathan said. This may increase cardiac contractility, so "until we know otherwise," patients with three or more cardiac risk factors, overt cardiovascular disease, or an age of 60 or older, "should probably have an exercise treadmill test before they start" taking Cialis, he added. He was the initial consultant and initial principal investigator for Cialis trials, and has been a consultant to Eli Lilly. He was an investigator in Levitra and Viagra studies and is a consultant to their manufacturers.
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|Title Annotation:||New & Approved; tadalafil from Eli Lilly|
|Publication:||Family Practice News|
|Date:||Dec 15, 2003|
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