Medication to treat erectile dysfunction

The primary drugs used to treat erectile dysfunction are the oral phosphodiesterase-5 (PDE-5) inhibitors.  Others include prostaglandins that are injected into the penis, however this module will focus on the oral treatment.

• The PDE-5 inhibitors work by blocking the phosphodiesterase enzyme, which would usually breakdown a substance in the body called cyclic guanosine monophosphate (cGMP).
• During normal sexual stimulation or arousal, cGMP is released in the penis which causes the dilation of localised blood vessels, producing an erection.
• The phosphodiesterase-5 (PDE-5) inhibitors block the phosphodiesterase enzyme slowing down the breakdown of cGMP, thus maintaining an erection.
• For treatment to have an effect, sexual stimulation is required to release cGMP, in order to achieve an erection.

* Refer to individual SPCs for full information - website links are available on our References' page.