A Look at Cialis' Effect on AMD Progression Shows No Effect | ASRS 2024

There’s reason to believe that the phosphodiesterase-5 (PDE5) inhibitors, such as Cialis (tadalafil) and Viagra (sildenafil), might have an unintended effect on the progression of age-related macular dystrophy (AMD).

The PDE5 inhibitors increase blood flow in the choroid, a middle layer of eye tissue sandwiched between the sclera and the retina that is filled with blood vessels. Increased choroidal blood flow could, in theory, be beneficial for people with “dry,” nonexudative AMD, which is characterized by a breakdown of the cells of the retina and thinning out of the macula, the center of the retina. The increased perfusion might provision the retina with additional oxygen and nutrients.

But the extra perfusion might worsen “wet,” exudative AMD, causing the leaky blood vessels to leak even more.

Tracy Z. Lang, a medical student at the University of Southern California Keck School ofMedicine in Los Angels, and colleagues presented findings of a study looking at the double-edged sword of PDE5 at the American Society of Retina Specialists annual meeting last week in Stockholm, Sweden. More specifically, they looked for evidence whether Cialis was associated with a worsening of early or intermediate AMD to advanced AMD, both the dry and wet types of the disease.

They conducted their study using Optum’s Clinformatics Data Mart database of approximately 32 million patients. They sifted through the records to identify patients with a diagnosis code indicating a diagnosis of early or intermediate AMD between January 2015 and December 2020. After a couple of other siftings, they homed in on 1,151 patients with an insurance claim record indicative of a prescription for tadalafil, which is marketed under the brand name Cialis as a treatment for benign prostatic hyperplasia and erectile dysfunction and as Adcirca as a treatment for pulmonary arterial hypertension. They matched those patients with those that didn’t have a tadalafil prescription. Lang and her colleagues also grouped the patient with tadalafil patients into low and high cumulative dosages groups.

The result? After two years, they didn’t see any statistically discernible difference between those with a tadalafil prescription claim and those without one as far as progression to advanced AMD. They also didn’t see any difference when comparing patients with high cumulative dosage to those with a relative one.

The good news-bad news implication is that while the PDE5 inhibitor wasn’t associated with a worsening of wet AMD, it also wasn’t associated with any protection against the progression of dry AMD.

In an interview at a session of the ASRS meeting devoted to poster presentations, Lang said the result may show that while tadalafil does, in fact, affect choroidal perfusion, the difference in blood show may not be clinically significantly.

Another possibility, Lang said, is that the two-year period of the study wasn’t long enough to detect tadalafil’s effect on dry and wet AMD and worsening to the advanced forms of the disease.