Manufactured by Pfizer and introduced in 1998, Viagra is the trade
name for the compound sildenafil citrate. This drug is used primarily to
treat erectile dysfunction
(ED), but it has also found niche uses as well for the treatment of
pulmonary arterial hypertension (PAH, high blood pressure in the lungs)
and altitude sickness. Viagra is similar in properties to both Cialis (tadalafil) and Levitra (vardenafil), which are also prescribed for ED.
By inhibiting an enzyme in the penis called cGMP-specific
phosphodiesterase type 5, Viagra acts by increasing blood flow that
produces an erection. Viagra acts as a vasodilator because it dilates
the blood vessels. The famous ‘blue pill’ is available in dosages of 25,
50 and 100 mg, and is recommended for use not more than once per day,
between 30 minutes to 4 hours prior to sexual intercourse.
If Viagra can produce greater blood flow in the penis, could it also
produce increased blood flow elsewhere in the body? And, as a result,
might it lead to increased oxygen delivery to the muscles in a way that
could enhance athletic performance?
Interestingly, we learned during the Balco investigation that many
professional baseball players and other athletes were using Viagra as an
on-field performance-enhancing agent. In fact, in 2008 Victor Balco
claimed that the use of Viagra was even more common than the use of
creatine.
The science about Viagra and athletic performance is actually very sparse.
Interest in this regard was stimulated by a study of 14 mountaineers
and trekkers by a group of investigators at the University of Giessen in
2004[1]. They studied the athletes using a cycling test at near sea
level (in Giessen), with a reduced-oxygen environment, and again at
Mount Everest Base Camp (5245 m). They found that Viagra increased the
maximum workload in each setting and concluded that “sildenafil is the
first drug shown to increase exercise capacity during severe hypoxia
both at sea level and at high altitude.”
There has been just one other study in humans to show a direct
benefit of Viagra on athletic performance [2]. A group of investigators
from Stanford hypothesised that Viagra would improve the cardiac output
(CO), arterial oxygen saturation (PaO2), and performance at altitude
(relatively low oxygen environment), but would have no effect at sea
level (with a normal level of atmospheric oxygen). They studied 10
cyclists with a 10 km time trial (TT) at both sea level and simulated
high altitude (3874 m). At sea level, Viagra had no effect on the
outcome measures. At altitude, Viagra produced higher CO, higher PaO2,
and a 15% improvement in time for the 10 km TT. On review, though, the
investigators found that there were actually 2 subgroups: a group of
Viagra responders, who improved their TT performance by 39% and a group
of non-responders who improved their TT performance by only 1% (which
was not statistically significant). The authors concluded that Viagra
can greatly improve cardiovascular function and performance in a
low-oxygen environment for certain individuals.
But, of course typical athletes don’t compete at altitudes of 2+ miles!
The issue of whether Viagra might affect athletic performance drew
the world’s attention heading into the Beijing Olympic Games in 2008. In
assembling its list of banned substances for 2008, the World
Anti-Doping Agency (WADA) wrote: “As regards sildenafil (Viagra), WADA
is aware of studies presented in relation to the potential of sildenafil
to restore pulmonary capacities at very high altitudes. WADA is
currently funding a number of research projects on the effects of
sildenafil at various altitudes. These projects are ongoing.” Indeed,
Viagra has not yet been added to the WADA list of banned substances.
In summary, then, Viagra is useful for the treatment of ED and PAH.
Although there is some evidence of performance-enhancing effects on
athletic performance (in some individuals) at altitude, there is no
evidence that Viagra improves performance in typical athletic
activities.
One thing we can be sure of is that Viagra greatly improves ED and
therefore the performance in the bedroom. Whether or not any Olympians
will be taking Viagra for on or off the track activities remains to be
seen. Either way, Medical Specialists Pharmacy can guarantee that their Viagra is genuine and from Pfizer, and is available to suitable patients after an online consultation
with one of our in-house Doctors. It will then be dispensed by our
in-house Pharmacy, and delivered to your required destination (home,
office or even the Olympics), within 24 hours.
References:
1. Ghofrani HA, Reichenberger F, Kohstall MG, et al. Sildenafil
increased exercise capacity during hypoxia at low altitudes and at Mount
Everest Base Camp. Ann Int Med 2004; 141:169-177.
2. Hsu A, Bamholt KE, Grundmann NK, et al. Sildenafil improves
cardiac output and exercise performance during acute hypoxia, but not
normoxia. J Appl Physiol 2006; 100:2031-2034.
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