Finding himself unable to perform was an alarming first for him. When Evans, a retiree who lives in Amherst, Ohio, told his doctor, he received a prescription for Viagra. That didn't help. At a follow-up appointment, he had some blood work done. It showed that his testosterone level had tanked, likely a side effect of one of the post-transplant medications he was taking. This time, his doctor sent him to a urologist, who prescribed a testosterone skin patch to boost the levels of the hormone in his blood. He's now been using patches for about five months.