READ THIS......


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Posted by Informed on September 22, 1998 at 00:58:45:

In Reply to: Viagra & Amyl posted by Big Balls on September 18, 1998 at 21:28:45:

Tell me you still don't believe your G.P. after you've finished.
Pay attention to paragraph 3.
__________________________________________________________________

Viagra (Sildenafil Citrate) Safety Information: "Dear
Doctor" Letter May, 1998

Contents:
"Dear Doctor" Letter
Nitric Oxide and blood pressure control
List of representative organic nitrates


May 1998

Dear Doctor,

I am writing to you both as the Medical director for the Sexual Health Team
of the U.S. Pharmaceuticals Division of Pfizer Inc. and as a former practicing
and board Certified Emergency Physician. As you may be aware, Viagra
(sildenafil citrate), the cGMP-specific type 5 phosphodiesterase (PDE5)
inhibitor discovered and developed by Pfizer, has recently received FDA
approval for the treatment of male erectile dysfunction. You may also be
aware, per the enclosed package insert, that the only contraindication for
taking Viagra is the concomitant administration of an organic nitrate.
We are aware that it is possible that the inadvertent combination of these
agents with Viagra may occur and could involve evaluation and treatment of
such patients by Emergency Physicians and/or pre-hospital emergency
personnel (paramedics/EMTs). Because we would not expect Emergency
Physicians to routinely be receiving information about this drug (based on its
indication) and in response to several inquiries that we have received on this
subject. I felt that it was important for the safety of patients taking Viagra that
I write this letter to all Emergency Physicians.

In addition to the approved package insert, I have enclosed a document
entitled "Nitric Oxide and Blood Pressure Control" that will provide you with
additional information on this subject. Please read it carefully and share it with
any of your colleagues who may not be aware of it. This explains the
physiologic mechanism underlying the contraindication, which is based on
data from several double-blind, placebo controlled interaction studies done
with either sublingual nitroglycerin or isosorbide mononitrate in which large
and sudden drops in systemic blood pressure occurred in the majority of
patients taking Viagra. A list of commonly prescribed short- and long-acting
nitrates available in the United States is also included.

It is well documented that sexual activity generally involves an increase in
cardiac work and myocardial oxygen demand. Per our package insert [see
PRECAUTIONS: GENERAL] for this reason, we are advising physicians to
consider the cardiac status of patients for whom they are planning to
prescribe Viagra and, in particular, NOT to prescribe it to patients who take
organic nitrates in any form, regardless of frequency. We have thought of
several possible scenarios in which Emergency Physicians need to be aware
of this interaction in order to make appropriate diagnosis and treatment
decisions. Those we have considered include:

1.the man who combines a nitrate and Viagra at home, becomes
severely hypotensive and is brought to an Emergency
Department. We are going to great lengths to educate every potential
prescriber and patient to the nitrate contraindication. However, in spite
of this, it is conceivable that a man may obtain Viagra who does use or
at least may have access to such medication. For example, a patient
with a history of angina could take Viagra and begin to engage in
sexual activity. If the aerobic effort involved in this were to precipitate
an anginal attack and he were to take (for instance) a sublingual
nitroglycerin while the Viagra was still on board, he could become
acutely hypotensive. As you know, the result of a precipitous drop in
blood pressure could range from no symptoms or mild symptoms of
hypotension such as dizziness or light-headedness, to syncope (most
likely postural), to a significant lowering of coronary perfusion and
conversion of an area of myocardial ischemia to infarction, with all of
its potential consequences. Such a patient could then easily end up in a
paramedic ambulance or an Emergency Department and require
treatment.
2.the man with no history of angina who takes Viagra, engages in
sexual activity and develops his first anginal episode. Such a
patient could be brought to an Emergency Department while still having
chest pain, where a short-acting nitrate may routinely be administered
to treat this. If the Emergency Physician were not aware of the
potential interaction described above and did not specifically question
that patient about Viagra, the same reaction described in scenario #1
above could be precipitated in the E.D., e.g., with nitroglycerin
administered sublingually, transdermally or intravenously. (NOTE: the
contraindication in our package insert also includes sodium
nitroprusside, which acts similarly as a NO donor.) A variant of this
would be the man who calls 9-1-1 upon developing chest pain and the
call is responded to by a team of paramedics or EMTs. In some
locales, these pre-hospital emergency personnel are permitted (either
by protocol or upon voice order from a physician) to administer a
short-acting nitrate on the scene or in the ambulance which could,
again, result in the possible consequences described above.
3.although we have not specifically studied this, we believe that
nitrates that are inhaled for recreational use (including amyl
nitrate/nitrite or "poppers" and others) will have the same
effect when combined with Viagra. As you probably know, these
are often used during sexual activity and it is easily conceivable that a
person would take Viagra, begin having sex and, at some point in the
process, inhale one of these substances.

In addition, although Viagra is only FDA approved for the treatment of male
erectile dysfunction, we are aware that women have started taking it, either
on their own or via an off-label prescription from a physician. Therefore,
although the scenarios described above would be more likely to occur in
men, is such off-label use continues, they could also occur in women.

I hope that the information provided here will be helpful to you with patients
you encounter who may be taking Viagra. If you would like additional
information about Viagra, please contact Pfizer's Medical Information
Department at 1-800-438-1985 or visit our Viagra website at
www.viagra.com. I thank you for your attention to this important matter.

Sincerely,

Richard L. Siegal, M.D.
Medical Director
Sexual Health
U.S. Pharmaceuticals
Pfizer Inc.
235 East 42nd Street
New York, NY 10017


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