You've probably noted the warning at the end of Cialis and Levitra commercials warning users to seek medical treatment if they have an erection lasting for more than four hours. Sure, most guys (and even some gals) think that having an erection that long doesn't sound all that terrible, even if it is inconvenient. However, the body wasn't designed to have that much blood stay in the groin for that long. It could actually damage the penile tissue, potentially causing erectile dysfunction, disfigurement, and even gangrene. In some cases, medication — or a little blood draw from the penis (YIKES!) — can solve the problem, but in more extreme cases, surgical treatment may be required, and complications could also result in permanent erectile dysfunction.

It's worth noting that Viagra doesn't carry the risk of priapism. It does, however, carry other strange side effects, most notably cyanopsia (aka, blue-tinted vision). The drug inhibits phosphodiesterase 6 in the body, which increases the sensitivity of the rods in the eyes. The rods are the most effective at picking up green-blue light, and make people see blue as they enjoy their erections.

Some people have difficulty experiencing orgasm, but a small percentage of individuals taking the anti-depressant Clomipramine have the exact opposite problem. In fact, users found that whenever they yawned, they would achieve orgasm. While most found it disturbing, at least one user enjoyed the effect and planned to stay on the drug as long as possible. Whatever works for her, at least, as long as she's tired.

It's hard for anti-depressant users to wean themselves off their prescriptions, not only for emotional reasons but also because the body tends to develop a dependency on the pills, resulting in withdrawal symptoms. One of the strangest and most disturbing side effects of anti-depressant withdrawal is known as "brain zaps," which are pretty much exactly what they sound like — the feeling of an electrical shock running through your head. While the sensation won't cause any long lasting damage, it can be painful and is often more mentally disturbing than it is physically bothersome.

This condition sounds (and looks) a lot worse than it is. After all, it doesn't do any harm and usually goes away without any medical treatment. Even so, it's pretty disturbing for your tongue to become black and fuzzy. Also, having a constant metallic taste in your mouth and bad breath isn't exactly pleasant. A prescription medication doesn't even cause this condition, but an over the counter upset stomach treatment does — Pepto Bismol. Pepto can also make your feces black, so you can have both ends of your digestive system look equally disturbing — all thanks to one fun treatment.

Whether you find the idea of immortal life depressing or all-too-intriguing, most people can agree that the worst part of being a vampire would be having to stay out of the sunlight for the rest of eternity. If the thought of having your flesh burn off as soon as you walk in the light disturbs you, then you should probably stay away from Levaquin and other fluoroquinolone anti-depressants, which boasts phototoxicity as one of its side effects. This means walking around outside can result in rapid and extreme sunburns, complete with blisters.

Fingerprints are becoming more and more important in our digital world as we increasingly use them to verify our identity on phones, and banks, hospitals, and airports. Unfortunately, some cancer drugs (most notably Capecitabine) have the side effect of hand-foot syndrome, which can result in vanishing fingerprints. Doctors warn those taking Capecitabine to travel with a physician's note to help clarify their situation.

Many medications can turn your urine a whole rainbow of hues — red, orange, green, blue, and even black. Rifampin, Isoniazid, and Phenazopyridine are some of the most common culprits when it comes to red and orange coloration; Promethazine, Cimetidine, Amitriptyline, Metoclopramide, and Indomethacin can cause a green tint; Triamterene, Rinsapin, and Viagra can all turn things blue; and Flagyl and furazolidone can make your pee black.

There's nothing wrong with having an occasional drink, sometimes playing the slots, or enjoying a calorie-filled meal every now and again, but when you start doing any of these things compulsively, that can be a problem. Unfortunately, drugs like Mirapex and Requip can cause compulsive behaviors that can make a light drinker an alcoholic, an occasional gambler an addict, an average person a shopaholic or a sex addict.