What are PDE5 Inhibitors?
PDE5 Inhibitors are a class of medicines used to treat Erectile Dysfunction.
There are 3 brands currently available. They are Levitra, Cialis and Viagra.
How do PDE5 Inhibitors work?
As the name suggest, PDE5 Inhibitors inhibit an enzyme called Phosphodiesterase-5 (PDE5).
During sexual stimulation, the body produces a chemical called cGMP (Cyclic Guanosine Monophosphate). cGMP causes the blood vessels in the penis to dilate thereby increasing blood flow to the penis and causing an erection. cGMP is broken down by PDE5. By blocking the PDE5, the level of cGMP in the penis increases and the blood vessels dilate more leading to a better erection.
What is the difference between the 3 PDE5 Inhibitors?
Viagra was the first PDE5 Inhibitor to be introduced. It is reported to cause the best hardness. It is also used to treat Pulmonary Hypertension. It comes in doses of 50mg and 100mg.
Cialis was the second PDE5 Inhibitor to be introduced. It has the longest duration of effect; up to 36 hours. Latest studies show that taking 5mg everyday has the same effect of taking 20mg before sex. This dosing schedule has the added benefit of improving the health of the inner lining (endothelium) of the blood vessels. It also disassociates the act of taking the pill and sex. Financially it is also beneficial for people who take 2 or more pills of 20mg a week.
Levitra is the third PDE5 Inhibitor to be introduced. It has the fastest onset; as little as 15 minutes and is reported to be the most potent. It is shown to be effective in people who have undergone Prostate Surgery or are suffering from chronic diseases such as Diabetes.
What are the side effects of PDE5 Inhibitors?
PDE5 Inhibitors all can potentially cause flushing, heartburn and headaches. Viagra can cause visual disturbances.
What are the dangers of PDE5 Inhibitors?
PDE5 Inhibitors must not be taken with any medicines that contain Nitrates. Please check with your Doctor before taking any PDE5 Inhibitors.
Do not take more than the prescribed dose.
Beware of counterfeit drugs. PDE5 Inhibitors are prescription drugs that can only be obtained from your Doctor. Do not buy drugs from an unlicensed source.
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About Dr. Tan
Dr. Tan graduated from the National University of Singapore in 2001. His residency was in the two largest public hospitals in Singapore; Tan Tock Seng Hospital and Singapore General Hospital.