There is a lot of misinformation going on here.
Blue tinted vision is not a common side effect. Though it has been reported there is no clinical trial study in which this was reported as a common effect.
No one has had to go to the hospital and have their blood drained.
Less than half a pill is not going to give you a hardon so severe you will need medical attention.
You should always consult your doctor before taking a prescription medication. They will be able to advise you on it's efficacy and go over the medical side effects without all the horror stories.
If you want to worry about side effects, worry about yohimbe...
Yohimbe is a tree bark containing a variety of pharmacologically active chemicals. It is marketed in a number of products for body building and "enhanced male performance." Serious adverse effects, including renal failure, seizures and death, have been reported to FDA with products containing yohimbe and are currently under investigation.
- Food and Drug Administration -- http://vm.cfsan.fda.gov/~dms/supplmnt.html