Does Avanafil Cause Liver Damage?

Avanafil is a selective inhibitor of phosphodiesterase type 5 (PDE5) used to treat erectile dysfunction. It is a relatively new drug with no reported cases of elevated serum enzymes or clinically significant liver damage.

Mechanism of Action

Avanafil is a selective inhibitor of phosphodiesterase type 5 (PDE5), which can inhibit the breakdown of cyclic guanosine monophosphate (cGMP), leading to relaxation of the penile corpus cavernosum and pulmonary vascular smooth muscle. This phosphodiesterase is mainly present in the penile corpus cavernosum and pulmonary vasculature.

Side Effects

Common side effects include dizziness, headache, facial flushing, hypotension, nasal congestion, and dyspepsia.

Clinical Trials

In clinical trials, 77% of men with erectile dysfunction (ED) were able to achieve an erection after taking Avanafil (Stendra), compared to 54% of men who took an ineffective placebo. Among patients with diabetes-related ED, 63% of men were able to achieve an erection after taking this medication, compared to 42% of men who took a placebo. Stendra enabled 57% of men with ED to engage in sexual intercourse (compared to 27% of men who took a placebo), and 40% of men with diabetes-related ED (compared to 20% of men who took a placebo).

Hepatotoxicity

Although Avanafil is restricted in its use, pre-market investigations have not found any cases of clinically significant liver damage or elevated serum enzymes associated with its use. Other PDE5 inhibitors such as sildenafil and tadalafil have been associated with rare cases of acute liver injury and jaundice. The onset of liver damage caused by these drugs ranges from a few days to three months, and the damage is typically cholestatic in nature. No immune hypersensitivity reactions or autoimmune diseases have been observed, and all cases have been self-limiting without residual damage or acute liver failure. Whether Avanafil can cause similar acute liver injury is currently unknown.

Mechanism of Injury

Although Avanafil is considered to be non-hepatotoxic, it has the potential to cause hypotension, which may lead to acute ischemic liver injury in patients with heart disease. Like other PDE5 inhibitors, Avanafil is metabolized by the hepatic cytochrome P450 (CYP 3A4) system.