Tadalafil is a drug used to treat male erectile dysfunction (impotence).
It was developed by the biotechnology firm ICOS and marketed worldwide
by Eli Lilly and Company under the brand name Cialis.
In the
United States, tadalafil has Food and Drug Administration approval
and became available in December, 2003 as the third impotence pill
after sildenafil (Viagra) and vardenafil (Levitra). Due to its 36-hour
effect it is also known as the weekend pill.
In 1998,
ICOS Corporation, and Eli Lilly and Company, commercialized the drug
for erectile dysfunction, and two years later they filed a new drug
application with the U.S. Food and Drug Administration for IC351;
the only difference was that this time they decided to call the drug,
Cialis. In May of 2002, Icos and Eli Lilly and Company reported to
the American Urological Association that the phase III tests show
that Cialis works for up to 36 hours, and one year later Icos and
Eli Lilly and Company received the U.S. FDA's approval for Cialis.
One advantage that Cialis has over Viagra is that tadalafil has an
half-life of 17.5 hours (and thus Cialis is advertised to work for
up to 36 hours) as compared to 4 hours half-life for sildenafil (Viagra).
Sildenafil
citrate, sold under the names Viagra, Revatio and generically under
various other names, is a drug used to treat male erectile dysfunction
(impotence) and pulmonary arterial hypertension (PAH), developed by
the pharmaceutical company Pfizer. Viagra
pills are blue and diamond-shaped with the words "Pfizer"
on one side, and "VGR xx" (where xx stands for "25",
"50" or "100", the dose of that pill in milligrams)
on the other. Its primary competitors on the market are tadalafil
(Cialis),
and vardenafil
(Levitra)..
As with
all prescription drugs, proper dosage is at the discretion of a licensed
medical doctor. The dose of sildenafil is 25 mg to 100 mg taken once
per day between 30 minutes and 4 hours prior to sexual intercourse.It
is usually recommended to start with a dosage of 50 mg and then lower
or raise the dosage as appropriate.
The drug
is sold in three dosages (25, 50, and 100 mg), all three costing about
US$10 per pill. Name-brand Viagra sildenafil is not scored and a fairly
hard coating makes it more difficult to accurately cut the pills in
half, even with a pill cutter.
