Download Chapter 18 – Pharmacological Approaches to the Treatment of

Chapter 18 – Pharmacological Approaches to the Treatment of Obesity
Questions
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Expressed in terms of “initial body weight”, what is the smallest amount of weight loss
that is considered clinically meaningful (i.e. beneficial to health)?
Describe the benefits of modest weight loss and compare those benefits to the typical
weight loss achieved with commonly used weight loss drugs that have been approved by
the Food and Drug Administration (FDA).
According to the FDA, weight loss drugs may be appropriate for persons with a BMI in
what range?
In terms of the Energy Balance Equation, how do obesity drugs work?
What are important issues for the physician and patient to discuss when weight loss
drugs are being considered?
What is Orlistat; how does it work (i.e., what is its mechanism of action); what are its
side effects?
What are the limitations of the currently approved drugs for weight loss
pharmacotherapy?
What are the major barriers to the use of weight loss pharmacotherapy?
Understanding Obesity: Biological, Psychological and Cultural Influences. Edited by Sharon Akabas, Sally Ann Lederman
and Barbara J. Moore. © 2012 John Wiley & Sons, Inc. Published 2012 by John Wiley & Sons, Inc.
Chapter 18 – Pharmacological Approaches to the Treatment of Obesity
Answers
1. Clinically meaningful or beneficial weight loss can be as small as 5% - 10% of initial body
weight.
2. The health benefits of modest weight loss, defined as 5%-10% of initial body weight,
include reduction of blood pressure and blood lipid levels (cholesterol and triglycerides),
improved control of blood glucose, improved sleep apnea and reduced risk or pain of
osteoarthritis. For people with impaired glucose tolerance or type 2 diabetes, weight loss
can resolve symptoms and/or reduce medication requirements. For most people, FDAapproved weight loss drugs, when paired with improvements in both eating and exercise
habits, can help produce clinically meaningful weight loss. Although obesity medications
used alone have only small effects on weight and all have side effects, the rationale for
their use is that they help more patients achieve clinically meaningful weight loss (when
those patients are already making lifestyle changes to reduce weight) at least doubling
the chances of achieving 5%-10% loss of initial body weight.
3. The Food and Drug Administration (FDA) recommends using obesity drugs in patients
with a BMI of 30 kg/m2 or more, or in persons with a BMI as low as 27 kg/m2 or more in
those with an obesity-related comorbid condition.
4. Energy balance is achieved when energy intake consistently equals energy expenditure.
Weight loss occurs when energy intake consistently is less than energy expenditure.
Obesity drugs act through a variety of mechanisms that relate to energy balance. They
can reduce energy intake by reducing energy absorption, or by decreasing hunger or
increasing satiety; some drugs can increase energy expenditure by increasing metabolic
rate or physical activity.
5. In eligible candidates for treatment based on BMI, it is important to assess patient
motivation and collaboratively set weight loss goals taking into account patient’s
circumstances (budget, location, comorbid conditions), weight history and history of
weight loss attempts. If pharmacotherapy is selected, weight loss is improved if the
patient understands the drug’s side effects and mechanism of action in terms of the
drug’s effect on the relevant component of energy balance.
6. Orlistat (trade name is Xenical® for the prescription drug; Alli® for the over-the-counter
or OTC drug) is a pancreatic lipase inhibitor. Orlistat reduces the breakdown and as a
consequence, blocks the absorption of dietary fat, thus reducing energy intake. It is
currently the only drug approved by the FDA for long term use for weight loss and weight
control. Because of its mechanism of action (acting on dietary fat), it has little effect in
subjects eating a low-fat diet and produces undesirable side effects in those eating a very
high fat diet. Like all other weight loss drugs, the effectiveness of orlistat depends on
continued use. The side effects of orlistat subside with patient experience. They include
borborygmi, flatulence, anal leakage, steatorrheal diarrhea and reduced levels of fatsoluble vitamins.
7. Limitations of the current family of weight loss drugs include: (1) Only some people
respond to these drugs with weight loss, (2) weight loss attained by responders is
relatively modest, (3) use may be associated with significant side effects, (4) use may
Understanding Obesity: Biological, Psychological and Cultural Influences. Edited by Sharon Akabas, Sally Ann Lederman
and Barbara J. Moore. © 2012 John Wiley & Sons, Inc. Published 2012 by John Wiley & Sons, Inc.
cause subtle health issues not readily detected in clinical trials lasting only 1 or 2 years,
and (5) the cost of life-long treatment can be substantial.
8. Barriers to pharmacological treatment of obesity include: (1) a limited number of safe,
clinically effective drugs are on the market, (2) lack of health insurance for patients, (3)
lack of physician reimbursement for drug treatment, counseling and follow-up, (4)
limited effectiveness of drugs relative to possible side effects and risks, (5) widespread
lack of recognition of the importance of treating obesity, and (6) reluctance of some
physicians to work in this field.
Understanding Obesity: Biological, Psychological and Cultural Influences. Edited by Sharon Akabas, Sally Ann Lederman
and Barbara J. Moore. © 2012 John Wiley & Sons, Inc. Published 2012 by John Wiley & Sons, Inc.