This medicine contains the active ingredient apomorphine hydrochloride, which is a type of medicine known as a dopamine agonist. It works by enhancing the nerve signals that cause an erection.

An erection is produced via a complex chain of events. The process is started with sexual stimulation from sight, smell, sound or touch. This causes nerve signals to be sent from the brain to the penis, which in turn cause the blood vessels in the penis to relax and widen. This allows the penis to fill with blood and makes it become erect.

Apomorphine works by enhancing the nerve signals that are sent from the brain to the penis during sexual stimulation.

It does this by mimicking the action of dopamine, which is a natural chemical called a neurotransmitter. Neurotransmitters are involved in sending signals along nerves. They act on special receptor sites in the nervous system to produce their effects. Dopamine acts on receptors called dopamine receptors, and this causes nerve signals with various effects to be sent. When dopamine acts on receptors in an area of the brain called the hypothalamus, it causes the nerve signals that produce an erection to be sent to the penis.

Apomorphine mimics the erection-producing effect of dopamine by stimulating the same dopamine receptors in the hypothalamus. This enhances the effect of natural dopamine that is produced as a result of sexual stimulation. The nerve signals to the penis are enhanced, and this results in blood entering the penis, ultimately causing it to become rigid and erect.

As apomorphine enhances the action of dopamine in producing an erection, it will only work once sexual stimulation has occurred. It does not increase sex-drive (libido) and is not an aphrodisiac. The sublingual tablet dissolves under the tongue, where it immediately enters the bloodstream, causing an erection in most sexually stimulated men in about 20 minutes.