Can Viagra affect the liver, or be taken with liver disease or cirrhosis?

Can Viagra affect the liver, or be taken with liver disease or cirrhosis? It is not known to harm the liver — liver injury has been reported only in rare single cases — but a diseased liver clears sildenafil more slowly. So with mild to moderate liver disease or cirrhosis the label suggests starting at 25 mg rather than the usual 50 mg, and severe liver disease rules sildenafil out, because it has never been studied there.

Can you take Viagra if you have cirrhosis?

With mild to moderate cirrhosis, yes, starting at a lower dose. Sildenafil is broken down in the liver (EMA — Viagra), and in volunteers with cirrhosis (Child-Pugh class A and B) the amount of sildenafil in the blood over time rose by 85% and its peak level by 47%, compared with healthy men of the same age. Hence the Australian product information: "Since sildenafil clearance is reduced in patients with hepatic impairment (e.g., cirrhosis) a 25 mg starting dose should be considered"; depending on how well it works and is tolerated, the dose may go up to 50 mg and 100 mg (Viagra PI (Australia)). The Viagra leaflet asks you to tell your doctor about any liver problems before you start (Viagra CMI). The same liver enzymes are why some HIV medicines change the dose too — see can HIV patients take Viagra?

Why does severe liver disease rule Viagra out?

Because it has never been tested there. "The safety of sildenafil has not been studied in the following sub-groups of patients and its use is therefore contraindicated" — and severe hepatic impairment heads the list (EMA — Viagra); the Australian product information adds "until further information is available", and notes that how the body handles sildenafil in severe liver impairment "has not been studied" (Viagra PI). The leaflet says not to take Viagra if "you have severe liver problems" (Viagra CMI). Vardenafil is ruled out with severe liver disease as well (EMA — Levitra).

Is Cialis different with liver disease?

Its dose is capped rather than lowered. In mild and moderate liver impairment, tadalafil levels after 10 mg were comparable to those in healthy men, and 10 mg is the recommended on-demand dose; there are no data on higher doses. In severe liver impairment (Child-Pugh class C) there is limited safety data, so the prescriber makes "a careful individual benefit/risk evaluation", and once-a-day dosing is not recommended (Cialis PI (Australia)). The leaflet: "if you have liver disease, the recommended dose of CIALIS is one 10 mg tablet" (Cialis CMI).

Can Viagra damage the liver?

Very rarely, if at all. The US National Institutes of Health's drug–liver injury database, LiverTox, records rare single case reports of acute liver injury with this group of medicines, mostly with sildenafil, and notes that long-term sildenafil use "has not been associated with serum aminotransferase elevations" — the liver enzymes in a blood test (LiverTox — PDE5 inhibitors; LiverTox — sildenafil). The European side-effect table for sildenafil lists no liver reactions (EMA — Viagra). The Australian product information lists abnormal liver tests among events seen in fewer than 2% of men in its trials, where "a causal relationship to VIAGRA is uncertain" (Viagra PI).

Does sildenafil lower the pressure in the liver's veins?

Not in the two small studies in people with cirrhosis. Because sildenafil works by dilating blood vessels, researchers tested whether it lowers the raised pressure in the portal vein that cirrhosis causes. In 12 people with compensated cirrhosis, sildenafil 25 mg (with a second 25 mg for most of them) lowered blood pressure at every time point but had no effect on portal pressure (Tandon et al., 2010). In 10 people given 50 mg, mean arterial pressure fell from 77 to 66 mmHg while blood flow to the gut and liver, their oxygen use and the portal pressure stayed unchanged (Clemmesen et al., 2008). It is not a treatment for cirrhosis.

Does cirrhosis cause erectile dysfunction?

Often. Pooling 14 studies of 770 men with cirrhosis, one review found erectile dysfunction in 79%, more often in decompensated cirrhosis, and linked it with diabetes, high blood pressure and the use of beta-blockers and diuretics (Yoo et al., 2023) — see beta-blockers and erectile dysfunction. Treatment can still work: in a trial of 140 men whose cirrhosis was short of the most severe stage (Child-Pugh score under 10), 62.9% improved by more than 5 points on an erection score on tadalafil 10 mg daily for 12 weeks, against 30% on placebo, with side effects and portal pressure no different between the groups (Jagdish et al., 2023). That was a trial dose; the label's once-a-day Cialis dose is 5 mg (EMA — Cialis).

The short answer

Sildenafil is not known to damage the liver. With mild to moderate liver disease or cirrhosis the label suggests starting at 25 mg, because the liver clears it more slowly; with severe liver disease it must not be used, and tadalafil is capped at 10 mg on demand. The doctor who treats your liver should know about any ED medicine you take. Other conditions are covered in our guide to Viagra and Cialis with special conditions.