apomorphine for erectile dysfunction

Last reviewed 01/2018

Efficacy rates with apomorphine are lower than those reported for PDE5 inhibitors, ranging from 26 to 55% and this product has now been discontinued in the UK (1)

Sublingual apomorphine is a treatment option for erectile dysfunction

• centrally-acting dopamine agonist - acts primarily on the D1 and D2 receptors, although it has a degree of selectivity for the latter
• effective after about 20 minutes
• does not affect sexual desire; only produces an erection with sexual stimulation
• it is well tolerated at doses producing a positive response in about 40-50% of patients (1)

Adverse effects include:

• headache
• nausea
• dizziness
• syncope - there is a risk of syncope of about 1 in 500 due to a vasovagal response, so patients must be advised to exercise caution when trying the drug for the first time, or when increasing the dose (2)
• there have been no reports of death, severe cardiovascular events such as myocardial infarction, cerebrovascular accidents or priapism throughout the phase 3 trials of apomorphine (3)

Contraindications include:

• history of unstable angina
• recent myocardial infarction
• hypotension
• severe heart failure

Note that (4):

• the maximum recommended dose in those with "severely impaired renal function" is 2mg
• men with "significantly impaired hepatic function" should be given the drug only if the "benefits outweigh the risks",and then started on a dose of 2mg, with "care exercised" over any dose increase
• "the limited published evidence suggests that apomorphine improves erectile dysfunction but is less effective thn sildenafil"
• "sublingual apomorphine is the only licensed oral drug for erectile dysfunction not absolutely contraindicated with nitrates, so may have a place in men taking such therapy "

The summary of drug characteristics must be consulted before prescribing this drug.

Reference:

• (1) Hackett G et al. British Society for Sexual Medicine guidelines on the management of erectile dysfunction. J Sex Med. 2008;5(8):1841-65.  
• (2) GP magazine (7/9/01), 44.
• (3) Prescriber (2002), 13 (10), 33-40.
• (4) Drug and Therapuetics Bulletin (2004); 42 (7):49-52