I've heard that the antidepressant drug "Paxil" wears off after a few
years and becomes inneffective. Where can I read some objective
studies about the drug that are not published by the drug companies?
Does Paxil have bad side effects over prolonged use?

Hello ah_oooh-ga

The generic name for Paxil is paroxetine, so this is the term I used
in my searches on Medline The studies I cite are all by
clinicians/scientists and have appeared in the peer-reviewed medical
literature. I have included the affiliations of the authors.

With respect to long-term use, there are studies reporting it still to
be effective after 48 weeks, 18 months and 4 years. I was unable to
find any study which followed patients for longer than 4 years. Side
effects appear to be fairly infrequent. I have listed those identified
by two studies, as well as a study which showed that paroxetine can
disrupt sleep, and two studies which looked at its effects on male
sexual function. I also provide a link to the drug information on
Medline Plus at the National Library of Medicine. This lists all
possible side effects that have been reported with the drug, as well
as drugs with which it might interact to cause adverse reactions.
However, this information does not related specifically to long-term
use. One of the studies I cite below found that side effects tend to
occur early on in therapy, and no new ones emerge later on. However,
paroxetine does seem to be more implicated than other similar drugs in
causing problems on withdrawal.

1. Chronic use of paroxetine has been associated with delayed
ejaculation and orgasm in men, and this was also confirmed in a study
in rats.  Depending on other factors, this could either be an
advantage or a disadvantage. This effect of paroxetine is used in the
treatment of premature ejaculation.

Study in humans: Clinical Psychopharmacology 2001 December;
21(6):556-560
 SSRIs and ejaculation: a double-blind, randomized, fixed-dose study
with paroxetine and citalopram.
Waldinger MD, Zwinderman AH, Olivier B.
Department of Psychiatry and Neurosexology, Leyenburg Hospital, The
Hague, The Netherlands.
URL to summary: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11763001&dopt=Abstract

Study in rats: Psychopharmacology (Berlin) 2002 March;160(3):283-289 
The selective serotonin re-uptake inhibitors fluvoxamine and
paroxetine differ in sexual inhibitory effects after chronic
treatment.
Waldinger MD, van De Plas A, Pattij T, van Oorschot R, Coolen LM,
Veening JG, Olivier B.
Department of Psychopharmacology, Rudolf Magnus Institute for
Neurosciences and Utrecht Institute for Parmaceutical Sciences,
Faculty of Pharmacy, Utrecht University, Utrecht, The Netherlands.
URL to summary: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11889497&dopt=Abstract

2. Paroxetine decreases the quality of sleep and can make people wake
up more during the night.
Journal of Clinical Psychiatry 2001 August; 62(8):642-652 
Effects of fluvoxamine and paroxetine on sleep structure in normal
subjects: a home-based Nightcap evaluation during drug administration
and withdrawal.
Silvestri R, Pace-Schott EF, Gersh T, Stickgold R, Salzman C, Hobson
JA.
Massachusetts Mental Health Center, Department of Psychiatry, Brigham
and Women's Hospital, Harvard Medical School, Boston 02115, USA.
URL to summary: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11561938&dopt=Abstract

3. Paroxetine is more likely than some other SSRIs to cause withdrawal
reactions when therapy is stopped. These reactions include: dizziness,
paraesthesia (pins and needles), tremor, anxiety, nausea and
palpitation.  However, this is still a fairly rare occurrence, with
0.3 reports received per 1000 prescriptions in the UK (a). Other,
reactions  include “problems with balance, sensory abnormalities, and
possibly aggressive and impulsive behavior. Although generally mild
and short-lived, discontinuation symptoms can be severe and chronic
and have a major impact on the patient's lifestyle.” (b)
a. British Journal Clinical Pharmacology 1996 December;42(6):757-763 
A comparison of the post-marketing safety of four selective serotonin
re-uptake inhibitors including the investigation of symptoms occurring
on withdrawal.
Price JS, Waller PC, Wood SM, MacKay AV.
Post-Licensing Division, Medicines Control Agency, Vauxhall, London,
UK.
URL to summary:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8971432&dopt=Abstract

b. Clinical Psychiatry 1997;58 Suppl 7:17-21; discussion 22 
Newer antidepressants and the discontinuation syndrome.
Haddad P.
Prestwich Hospital, Manchester, United Kingdom.
URL to summary:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9219489&dopt=Abstract

There is also a comparative table of the number of cases with problems
on withdrawal, as drawn up by the Monitoring Centre in Uppsala, which
runs the WHO drug monitoring program with input from around 60 main
collaborating countries
http://www.socialaudit.org.uk/4390EU61.htm

4. A full list of all reported side effects and interactions with
other drugs is available on Medline Plus. However, this does not
relate specifically to long-term use.
http://www.nlm.nih.gov/medlineplus/druginfo/uspdi/202717.html

5. I found the following reports relating to long-term use.

a. Effective for at least 18 months
Journal Clinical Psychiatry 1999;60 Suppl 20:21-25 
Continuation and maintenance pharmacotherapy in geriatric depression:
an open-trial comparison of paroxetine and nortriptyline in patients
older than 70 years.
Walters G, Reynolds CF 3rd, Mulsant BH, Pollock BG.
The Mental Health Clinical Research Center for Late-Life Mood
Disorders, Department of Psychiatry, University of Pittsburgh, PA
15213, USA.
URL to summary:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10513854&dopt=Abstract

b. Effective for at least 48 weeeks
Acta Psychiatrica Scandinavica 1997 Feb;95(2):153-160 
Long-term evaluation of paroxetine, clomipramine and placebo in panic
disorder. Collaborative Paroxetine Panic Study Investigators.
Lecrubier Y, Judge R.
INSERM, Hopital La Salpetriere, Paris, France.
URL to summary:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9065681&dopt=Abstract

c. Effective for at least 4 years
Clinical Psychopharmacology 1993 Dec;13(6 Suppl 2):28S-33S Long-term
treatment of major depressive disorder with paroxetine.
Duboff EA.
Center for Behavioral Medicine, Denver, CO 80212.
“The most common adverse events reported during long-term treatment
with paroxetine were somnolence, nausea, headache, and sweating...
Side effects tended to occur early during therapy; and no new side
effects emerged during the long-term extension. These results suggest
that paroxetine is effective and well tolerated in the long-term
treatment of depression.”

If you are interested in reading the comments of 30 patients who took
paroxetine for various periods from several days to several years, and
had very different experiences with the drug, you can find these at
http://remedyfind.com/rem.asp?ID=3990&lPageNum=2


Search strategy
On Medline: 1. paroxetine, chronic use  2. paroxetine, long-term use
On Google: 1. paroxetine "ten years" 2. paroxetine, "long-term use"

I was too depressed to rate this question for 4 months. Couldn't bring
myself to wade through the info to even rate it. Now I have. It's very
good information and well summarized too.  You quoted very good
studies, very scientific & legitimate.
I was kinda hoping you'd turn up some home made grass roots sites too,
warning of the evils of Paxil. There's books full of dire warnings
like Potatos Not Prozac, I thought there'd be websites too, but I
should have put that in my question.  Thanks again, good job.