Vardenafil adverse effects

The most dramatic difference between the three agents is tadalahl s extended duration of action, earning it the nickname the weekender drug. While sildenafil and vardenafil have average half-lives of 3 to 4 hours, tadalafil s half life is approximately 18 hours.18 The extended half-life allows for more spontaneous sexual activity over a couple of days, but may increase the duration of adverse effects and liklihood of drug interactions or sildenafil. 

Unless otherwise stated, general information applies to the entire class of phosphodiesterase inhibitors. Sildenafil is highlighted because it was the first to be marketed and is the most thoroughly studied. The newer agents tadalafil and vardenafil have different pharmacokinetic profiles (Table 83-3), drug-food interactions, and adverse effects. 

Sildenafil and vardenafil decrease systolic/diastolic blood pressure by 8 to 10/5 to 6 mm Hg for 1 to 4 hours after a dose. Although most patients are asymptomatic, multiple antihypertensives, nitrates, and baseline hypotension increase the risk of developing adverse effects. Although tadalafil does not decrease blood pressure, it should be used with caution in patients with cardiovascular disease because of the inherent risk associated with sexual activity. 

PHOSPHODIESTERASE TYPE 5 INHIBITORS (e.g. sildenafil, tadalafil, vardenafil) GRAPEFRUIT JUICE Possibly t efficacy and t adverse effects, e.g. hypotension Small t in bioavailability, t variability in pharmacokinetics, i.e. interindividual variations in metabolism Safest to advise against intake of grapefruit juice for at least 48 hours prior to intending to take any of these preparations. When necessaiy, the starting dose of sildenafil should not exceed 25-50 mg and that of tadalafil 10 mg. Avoid co-administration with vardenafil... 

Adverse effects are short-lived, dose-related, and comprise headache, flushing, nasal congestion and dyspepsia. High doses can inhibit PDE6 which is needed for phototransduction in the retina, and some patients report transient colour vision disturbance. (The more recently developed PDE5 inhibitors, cialis and vardenafil, appear less likely to cause visual upset.) Priapism has been reported. 

Priapism is a rare adverse effect of phosphodiesterase inhibitors, particularly sildenafil and vardenafil, which have shorter plasma half-lives than tadalafil. When priapism has occurred, this has been associated with excessive doses of the phosphodiesterase inhibitor or concomitant therapy involving other erectogenic drugs. 

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