Manhoodtherapies Singapore/83766338

To understand how these drugs work we need to understand the 
mechanism of an erection.  Basically  in this rising of an erection 
two enzymes come into play.  One is the penile hardening enzyme called 
cGMP  -guanosinemonophosphate.  The other enzyme which is the penile 
softening enzyme is called phosphodiesterase or pde5.  
Why do pde5 exists?    Pde5 exists to regulate erection 
because a man is not supposed to be perpetually erect.  The flaccid penis 
is the natural state.

When a man gets sexually aroused his brain sends a signal to cGMP 
to cause the red blood cells to release nitric oxide to  cause smooth
 muscles in the penis to relax and subsequently engorged. 
 So after an orgasm the brain then sends another signal to turn 
down the production of the cGMP.  Then the Pde5 can complete its 
regulation of an erection and the penis returns to its natural state.    

And if this pde5 is too active in a man or there are just 
too many in your body it will reduce the cGMP levels in the body 
and make it difficult to achieve a usable  erection. So the aim of 
these drugs is to block or inhibit the function of the pde5 
- the penile softening enzyme.

Side effects
Most of of the pde5 are found in the genitalia of the man. 
That being said, there are minute amounts found in other parts 
of the body, face,  stomach, intestines, blood vessels of the brain 
even in the erectile tissues of the nose.  The effect of Pde5 inhibitor
on all these areas is the same and makes the smooth muscles relax.

So the drug works in every organ that contains pde5. Relaxing the 
smooth muscles. That may be what you are hoping only  in your penis. 
The effect however is the same for all these organs in the body and to 
prolong the effect of cGMP and make smooth muscles relax.  
In the brain however it causes headaches, in the nose 
nasal stuffiness, in the face flushing, in the eyes blurred vision 
and a bluish/greenish tinge to your sight. It can also cause 
vascular dilation and a precipitious drop in the blood pressure 
especially if taken  with alcohol, or combined with blood pressure 
medications or alpha blockers. The risks are not to be ignored in older 
men with low blood pressure or very high blood pressure. 
These people should try and avoid these drugs.

These drugs work well in relatively healthy men and do not work well in  
men with diabetes or those with low testosterone levels or 
in men who have damaged nerve after a radical prostatectomy. They 
are not so effective in diabetics because it is harder for 
diabetics' smooth muscles to relax as they have a higher and tigther tone 
in their smooth muscles and the effect of cGMP caused by these Pde5 drugs 
may not be enough to create and prolong erection.  These drugs are 
also not so effective in those with low testosterone because when 
the blood testosterone is low it is harder for the cells to relax.  Until  
hormonal imbalance is corrected the drugs will not have enough effect  
to correct the ED problem.   Another disadvantage with the drug is for 
it to work a man has to be sexually aroused.
There are some novel ED drugs available that can cause an erection 
without the man feeling aroused.