If you have erectile dysfunction, you don’t have to shop for the increasingly rare rhinoceros horn or the often deadly Spanish fly, which is made from the remains of the blister beetle. There are hundreds of other reputed aphrodisiacs, but none have been found to work. What about Viagra, Levitra, and Cialis? You don’t even have to inject a drug into your penis, which was the best thing that Western medicine had to offer just eight years ago. Before that, the best you could do was either use a pump to draw blood into your penis or a penile implant, which meant the surgical placement of plastic rods in your penis. Ouch! Now, we have a choice of three quite effective and well tested oral drugs for erectile dysfunction (often described by the acronym ED). They are not aphrodisiacs, because they will not increase sexual drive. They work by blocking an enzyme called phosphodiesterase-5, or PDE-5. This helps the smooth…