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.
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