New formulation

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.

MUSE (Astra)
urethral delivery system containing 125 microgram, 250 microgram, 500 microgram and 1000 microgram
Approved indication: erectile dysfunction
Australian Medicines Handbook Section 13.3

Until the approval of sildenafil in 1998, the most effective drug treatment for erectile dysfunction was prostaglandin E1 (alprostadil)(see `The management of erectile dysfunction' Aust Prescr 1998;21:46-8). This treatment had the disadvantage of having to be given by intracavernosal injection. The same effect can now be achieved by inserting this new formulation into the urethra.

When practitioners consider prescribing the new formulation, they will still need to instruct patients how to use it. Patients must urinate before inserting the alprostadil pellet. If the detailed instructions are followed, the drug is quickly absorbed through the urethral mucosa.

A starting dose of 250 micrograms is recommended. If this is ineffective, the dose can be increased on a later occasion; no more than two doses can be given in 24 hours.

Penile pain is a common adverse effect and urethral bleeding occurs in 5% of patients. Priapism is infrequent. Although alprostadil is not contraindicated for patients with cardiovascular disease, it can cause hypotension.

A condom must be used during intercourse with a pregnant woman because of the effect of alprostadil on the uterus.

Although it can be expected to work more quickly than oral sildenafil, this product is more difficult to use. It may have a role in patients who require drug treatment, but cannot take sildenafil, for whom it is contraindicated or does not work.