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From: dyer@spdcc.COM (Steve Dyer)
Newsgroups: sci.med.aids
Subject: Re: Fansidar
Message-ID: <26084@shemp.CS.UCLA.EDU>
Date: 28 Jul 89 16:33:21 GMT
References: <26079@shemp.CS.UCLA.EDU>
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In article <26079@shemp.CS.UCLA.EDU> phil@wubios.wustl.edu writes:
>My Dr. has suggested that I start some additional preventitive
>measures.  He is a leader in providing AIDS care in San Francisco.  He
>suggested that Aerosol Pent. has become "trendy" and even more is not
>systemic to the entire body.  Therefore I am on Fansidar, once a week.
>I have been for six weeks, with no side effects that I am aware of. My
>blood is monitored ever two weeks for "internal" problems. In looking
>Fansidar up in the PDR, it only talks about it as a drug for Malaria.
>Does anyone have additional information.......?  Please respond to
>sci.med.aids if you do.   THANKS

First, understand that I'm not a doctor and am not intimately familiar with
recent trends in chemoprophylaxis for AIDS-related infections.  There is a
lot of nuance which gets lost in answering things over the net, and you
should ask your doctor these questions also.  I can give you only general
information, and not any opinions informed by practice and experience.
If your doctor is a leader in AIDS care in SF, he must be pretty good.

One of the pluses for aerosolized pentamidine is precisely that it
delivers the drug to the lungs, sparing the rest of the body.  Pentamidine
had previously had a reputation for being a rather toxic drug because it
had to be given systemically.  It's much less toxic as a localized aerosol.

Fansidar is a combination consisting of a long-acting sulfa drug
(sulfadoxine) and a long-acting dihydrofolate reductase inhibitor,
pyrimethamine.  Given once a week, these drugs persist in the body
for about a week.  Fansidar is frequently used for malarial chemo-
prophylaxis in areas where chloroquine is no longer effective.
This, and the treatment of malaria, are still its only FDA-approved
indications.

The mechanism of action of Fansidar is similar to that of Bactrim or
Septra, a similar combination drug which uses the short-acting agents sulfa-
methoxazole and trimethoprim.  Such a combination suppresses the
growth of _P . carinii_.  Bactrim or Septra has been very effective
in treating active PCP infections, but many AIDS patients tolerate it
very poorly, exhibiting side-effects which are infrequent in other populations.

The concern about Fansidar is that the so-called long-acting sulfa drugs
can be very toxic, in unpredictable and idiosyncratic ways.  Drugs like
sulfadoxine were popular in the early 60's but were ultimately withdrawn
because of their propensity to cause dangerous side-effects at a rate
much higher than the ordinary sulfa drugs which need to be taken several
times a day.  Some of the side effects include a variety of blood disorders,
including dangerously low white cell counts and halting of red cell production,
and skin reactions ranging from rashes and sun sensitivity to much more
serious syndromes.  These are unpredictable reactions, and still rare, but
more frequent than people on other sulfa drugs.  Now, you are having your
blood tested every two weeks to make sure that you aren't exhibiting early
signs of a reaction.  Similarly, you should probably report any rash
which occurs to your doctor.

The question which I cannot answer, but your doctor probably can, is
whether Fansidar is effective enough in preventing PCP flareups that
the small risk of potentially dangerous side-effects is worth taking.
It might very well be, given the debilitating nature of PCP infections
in many people with AIDS.

-- 
Steve Dyer
dyer@ursa-major.spdcc.com aka {ima,harvard,rayssd,linus,m2c}!spdcc!dyer
dyer@arktouros.mit.edu