Vardenafil (Levitra) Australia
March 18th, 2013
Vardenafil is a new PDE5 inhibitor that, like sildenafil and tadalafil, is highly effective in the treatment of ED. Its molecular structure is similar to sildenafil, and it has a half-life that is similar to sildenafil at about 4 h. There are less cardiovascular data available for vardenafil vs sildenafil or vardenafil. Its effect on blood pressure and heart rate in normal volunteers is minimal. One preliminary study done in normal healthy volunteers in the sitting position suggested that there was no nitrate interaction. However, whether this would be true in patients with cardiovascular disease or risk factors for cardiovascular disease in the standing position is not known. When vardenafil was released in the United States, it received a nitrate contrainindication, as will be likely for the entire class of PDE5 inhibitors.
In patients with hypertension, who usually start out with a higher baseline blood pressure than normal volunteers, vardenafil was associated with a small fall in blood pressure and small increase in heart rate compared to placebo. In all hypertensive patients, vardenafil reduced mean standing systolic blood pressure by –4.6 mmHg and mean standing diastolic blood pressure by –3.1 mmHg; it increased heart rate by 2 beats/min. In contrast, placebo reduced mean standing systolic blood pressure by –0.1 mmHg, mean standing diastolic blood pressure by –0.02 mmHg, and heart rate by –0.2 beats/min. There was no difference in response to vardenafil in patients on or not on antihypertensive medicines (which included angiotensin converting enzyme inhibitor, calcium blocker, β- or α-blockers, diuretics, and angiotensin receptor blocker). In patients not on antihypertensive medicines, vardenafil reduced standing systolic blood pressure by –4.2 mmHg, mean standing diastolic blood pressure by –2.6 mmHg, and increased heart rate by 2.0 beats/min. In patients taking one or more antihypertensive medicines, vardenafil reduced mean standing systolic blood pressure by –5.1 mmHg, mean standing diastolic blood pressure by –3.7 mmHg, and increased heart rate by 1.9 beats/min. Importantly the incidence of adverse cardiovascular events—angina, arrhythmia, MI, or syncope— was low and similar in placebo vs vardenafil-treated patients with or without concomitant use of antihypertensive medicines. The conclusion of this study was that concomitant antihypertensive medicines plus vardenafil use did not result in changes in blood pressure or elevations of heart rate of clinical concern compared to changes observed with vardenafil alone. In another study it was observed that vardenafil was well tolerated in men with ED on antihypertensive medicines and was highly effective in improving erectile function. Var denafil (5, 10, and 20 mg) significantly improved erectile function domain, penetration, and maintenance of erection rates in these men.
However, vardenafil is contrainindicated in patients taking α-blockers based on hypotension that occurred when vardenafil was administered to patients on terazosin and to a lesser extent on tamsulosin in one study.
Vardenafil Australia caused small increases in QT interval in healthy men at both therapeutic (10 mg) and supratherapeutic (80 mg) doses. It is recommended that patients with congenital QT prolongation and patients receiving class IA (quinidine, procainamide) antiarrhythmic agents or class II (amiodarone, sotalol) antiarrhythmic agents avoid vardenafil.
In a double-blind, crossover, single-dose study of men with CAD who had reproducible exercise tolerance tests, either vardenafil 10 mg or placebo was given 1 h prior to an exercise treadmill test (5–10 METS; ref. 45). Vardenafil did not alter total treadmill exercise time or time to angina pectoris. However, vardenafil did significantly prolong the time to ST-segment depression ≥1 mm (381 ± 108 s with vardenafil vs 334 ± 108 with placebo; p = 0.0004). Vardenafil was well tolerated in these men. Facial flushing and headache were the most common side effects reported. Changes in heart rate and blood pressure were similar between vardenafil and placebo. The study concluded that vardenafil did not impair the ability of patients with stable CAD to exercise at levels that were similar to those for sexual activity.
In general, then, vardenafil, like sildenafil sydney and tadalafil, is a mild vasodilator, is, in general, safe to administer in patients on antihypertensive medicines (except α-blockers), and does not exacerbate ischemia. None of the PDE5 inhibitors have been shown to definitely precipitate MI. However, as reviewed elsewhere in this book, there is a small but finite increased risk of a cardiovascular event with sexual activity and any drug or therapy that enables men with ED to now engage in sexual activity will expose them to that risk. In general, PDE5 inhibitors are withheld from unstable cardiac patients or those on organic nitrates. The Princeton Consensus Statement and Guidelines of the ACC/AHA serve as useful general approaches to the management of sexual dysfunction in the cardiac patient. These guidelines, which are reviewed elsewhere in this volume, should be kept in mind when physicians are considering prescribing PDE5 inhibitors for ED.
Categories: Levitra