Some of the views expressed in the following notes on newly approved products should be regarded as preliminary, as there may have been limited published data at the time of publication, and little experience in Australia of their safety or efficacy. However, the Editorial Executive Committee believes that comments made in good faith at an early stage may still be of value. Before new drugs are prescribed, the Committee believes it is important that more detailed information is obtained from the manufacturer's approved product information, a drug information centre or some other appropriate source.

Levitra (Bayer Australia)
5 mg, 10 mg and 20 mg tablets
Approved indication: erectile dysfunction
Australian Medicines Handbook section 13.3

Vardenafil is the third inhibitor of phosphodiesterase type 5 to be marketed in Australia. Like sildenafil and tadalafil it raises concentrations of cyclic guanosine monophosphate in the corpus cavernosum of the penis. This increases the likelihood of an erection in response to sexual arousal.

Patients take vardenafil 25 to 60 minutes before attempting intercourse. Although nearly 50% of men with erectile dysfunction will respond to a placebo, vardenafil will produce an erection in 68-80% depending on the dose. Response rates are lower in men with diabetes and those who have had their prostate removed.

Vardenafil and sildenafil have similar half-lives (approximately four hours).Like the other phosphodiesterase inhibitors, vardenafil is metabolised by cytochromeP450 3A4. This results in potential interactions with drugs such as erythromycin.Vardenafil should not be prescribed for patients taking potent CYP3A4 inhibitors such as ketoconazole and ritonavir. A low dose is recommended for people with reduced hepatic function. The drug is contraindicated in patients taking nitrates.

As vardenafil has vasodilatory effects it can cause headache, flushing and reduced blood pressure. It is contraindicated in patients with severe cardiovascular disorders, including unstable angina and a recent history of myocardial infarction.

Studies comparing the three oral treatments for erectile dysfunction are needed. A literature review found that there are no relevant differences in their selectivity for phosphodiesterase type 5 and they have similar efficacy in helping patients achieve an erection.1