An erectile dysfunction drug that is also used to treat symptoms like sudden urgency and frequency, which are associated with an enlarged prostate in men, may heighten the risk of the serious eye condition, glaucoma, finds a large comparative study published online in the British Journal of Ophthalmology. Tadalafil, like sildenafil (Viagra), belongs to a class of drugs called phosphodiesterase type 5 inhibitors (PDE5i). To extend the evidence base, the researchers wanted to find out if tadalafil, a long-acting PDE5i, is associated with heightened glaucoma risk, when prescribed for the management of urinary tract symptoms associated with an enlarged prostate (benign prostatic hyperplasia). They assessed how likely both groups of men were to develop glaucoma, ocular hypertension, and to start treatment for glaucoma after 5 years. And most study participants were White, so the findings may not apply to men of other ethnic backgrounds, they add.