Tadalafil is a potent new medication for the treatment of male sexual dysfunction - specifically erectile disorders. It works faster, is more potent, and has an improved side-effect profile over Sildenafil citrate (Viagra). One major benefit is that tadafenil is not contraindicated in patients with heart disease or those taking high blood pressure medications - opening up another avenue of treatment for patients with both conditions. The benefits of the drug as compared to sildenafil appear to be related to its increased specificity for the target enzyme.

Pharmacologic class

Phosphodiesterase-5 inhibitor
Brand Name
Male erectile dysfunction (ED)
PDE-5 inhibitors work by blocking the phosphodiesterase-5 enzyme controlling relaxation of the smooth muscles at the base of the penis. This allows for increased blood flow to the penile corpora cavernosa and corpus spongiosum. The body breaks down tadalafil using the same enzymatic processes as for nitrates. I has a mean half-life of just over seventeen hours and low clearance through the liver.
Concomitant therapy with nitrates can cause severe lowering of blood pressure. (This is a class effect for PDE-5-inhibitors.)
Confirm the treating diagnosis. Penile deformation (such as Peyronie's disease) or a predisposition to praipism. Anyone for whom sex is inadvisable. Bleeding disorders or active peptic ulcers.
Nitrates (both short and long-acting forms)
Adverse Reactions
The most commonly seen side-effects in studies were headache, flushing, myalgias (muscle-aches), and in a few cases, low back pain. These were dose-dependant and tended to improve over time.
Additional Information
Tadalafil is rapidly absorbed without regard to meals. Onset of action has been noted in some cases to occur in less than thirty minutes after dosing. The brand-name form of tadalafil, Cialis, is being co-developed by ICOS Corporation and Eli Lilly and Company.
Date of most recent Update
September 25, 2002
Further information is available in the writeup for the brand name of this medication

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