FENTERMIN DOENSNT INCREASE HYPERTENSION

These are times where losing weight should not concur with drug induced hypertension. This article is interesting in this respect.

1. to the editor
letter
Diabetes, Obesity and Metabolism13: 963–964, 2011.
©2011 Blackwell Publishing Ltdlettertotheeditor
Phentermine therapy for obesity does not elevate blood
pressure
To the Editor:
The report by Kang et al. [1] of a clinical trial with a new
diffuse-controlled release of phentermine for obesity is timely
because phentermine is currently one of the few remaining
approved drugs for obesity pharmacotherapy. We agree that
the study data supports the authors’ conclusions that this
formulation of phentermine is a safe and effective treatment
adjunct for treating obesity. We also agree that further long-
term studies of phentermine should be undertaken. In our
opinion, phentermine pharmacotherapy for obesity is much
safer than is commonly assumed. Phentermine offers a high
potential of substantial benefit to obese patients, particularly
those with moderate elevations of blood pressure, and it
should be the first choice medicine when pharmacotherapy
is considered for most obese patients.
Kang et al. mentioned that phentermine may elevate blood
pressure, even though they observed the opposite effect. Other
than a few anecdotes, there is little or no evidence in the
peer-reviewed medical literature to support the often repeated
conjecture that phentermine, when chronically administered,
can elevate blood pressure. The clinical trial reports cited by
Kang et al. either did not report blood pressures or reported that
phentermine-treated subjects had declines in blood pressure.
The meta-analyses cited discuss elevations of blood pressure
as adverse effects but provide no supporting data. Average
blood pressures are known to decline when obese patients
lose weight without pharmacotherapy [2]. Obesity treatment
specialists experienced with phentermine have known for
some time that average blood pressures also decline in
patients when phentermine is added to weight loss therapy.
These observations have recently been confirmed in two
observational reports from private practices, one short term [3]
and the other long term [4]. In clinical trials for Qnexa, a
combination of phentermine and topiramate, investigators also
observed that the blood pressure declined in treated patients
with the most pronounced declines occurring in patients
with preexisting hypertension [5]. The long-term phentermine
study mentioned above [4] found that phentermine-treated
patients with preexisting hypertension had the greatest declines
in blood pressure, patients with preexisting prehypertension
had lesser declines, while patients with initial optimum
blood pressures (<120/80) had no significant blood pressure
changes. Long-term phentermine-treated patients had better
success with weight loss maintenance and had blood pressure
declines that were persistent so long as weight loss was
maintained.
The preponderance of published evidence suggests that
blood pressure elevation because of phentermine is rare rather
than common in the context of obesity management.
Phentermine was approved for obesity treatment in 1959,
long before the chronicity of obesity was acknowledged and
the Food and Drug Administration (FDA) began to require
long-term clinical trials for obesity drugs. In response to a long
simmering controversy, and after an extensive reevaluation
of these obesity drugs, in 1977 the FDA formally reaffirmed
amphetamine and its congeners, including phentermine, to
be effective for obesity treatment. However, in response
to controversy regarding the addiction potential of the
amphetamine congeners, and because most of the patients
in clinical trials had only taken the drugs for 12 weeks, the FDA
decided that these drugs should be used only a ‘few weeks’ [6].
At that time, many private practice obesity treatment specialists
already had 18 years of experience with these amphetamine
congeners, had found them to be both effective and safe, and
were using them long term for patients in their practices. Few
of these practitioners discontinued their patients’ medications
when the FDA relabeled them for short term use only. (W.L.
Asher, pers. comm.). Although the notion that phentermine
should be used beyond 12 weeks did not begin to gain traction
in the medical literature until after Weintraub et al.’s studies
appeared beginning in 1984 [7], occasional earlier reports had
suggested that the drugs could be used for longer durations than
12 weeks [8]. A recent survey of obesity treatment specialists
in the US revealed that the majority of the specialists polled
now use phentermine, diethylpropion, and phendimetrazine
long term [9]. We conclude that long-term phentermine
use has long been common in the US despite the FDA
labeling.
We concur with Kang et al., that additional phentermine
efficacy and safety studies should be conducted. Since many
physicians already use phentermine long term, the studies
should be long term, at least 1 year in length.
E. J. Hendricks
∗
Center for Weight Management, Roseville, CA 95661, USA
R. B. Rothman
Belite Medical Center, Fairfax, VA 22030, USA
∗
Center for Weight Management, 2510 Douglas Boulevard,
Suite 200, Roseville, CA 95661, USA
E-mail: [email protected]

2. lettertotheeditor DIABETES, OBESITY AND METABOLISM
Conflict of Interest
Dr Hendricks wrote the draft and Dr Rothman revised the
letter. Both authors agreed on the final draft and have no
conflicts of interest.
References
1. Kang JG, Park CY, Kang JH, Park YW, Park SW. Randomized controlled trial to
investigate the effects of a newly developed formulation of phentermine
diffuse-controlled release for obesity. Diabetes Obes Metab 2010;12:
876–882.
2. Aucott L, Rothnie H, McIntyre L, Thapa M, Waweru C, Gray D. Long-term
weight loss from lifestyle intervention benefits blood pressure? a systematic
review. Hypertension 2009;54: 756–762.
3. Rothman RB. Treatment of obesity with ‘‘combination’’ pharmacotherapy.
Am J Ther 2010;17: 596–603.
4. Hendricks EJ, Greenway FL, Westman EC, Gupta AK. Blood pressure and
heart rate effects, weight loss and maintenance during long-term
phentermine pharmacotherapy for obesity. Obesity (Silver Spring) 2011
[Epub ahead of print].
5. Gadde KM, Allison DB, Ryan DH et al. Effects of low-dose, controlled-
release, phentermine plus topiramate combination on weight and
associated comorbidities in overweight and obese adults (CONQUER):
a randomised, placebo-controlled, phase 3 trial. Lancet 2011;377:
1341–1352.
6. Colman E. Anorectics on trial: a half century of federal regulation of
prescription appetite suppressants. Ann Intern Med 2005;143: 380–385.
7. Weintraub M. Long-term weight control study: conclusions. Clin Pharmacol
Ther 1992;51: 642–646.
8. Craddock D. Anorectic drugs: use in general practice. Drugs 1976;11:
378–393.
9. Hendricks EJ, Rothman RB, Greenway FL. How physician obesity specialists
use drugs to treat obesity. Obesity 2009;17: 1730–1735.
964doi:10.1111/j.1463-1326.2011.01435.x Volume 13 No. 10October 2011