Apr 15, 2002 Table of Contents

Tips

From Other Journals

When to Use Drug Therapy in the Treatment of Obesity

Am Fam Physician. 2002 Apr 15;65(8):1675-1679.

With obesity affecting more than one third of Americans and more than one half of certain populations (e.g., Hispanic females), its important role in overall morbidity and mortality is clear. While recognition of the problem is straightforward, management is not. Initial failure rates for treatment of obesity are high, and relapse after successful weight loss is the norm, not the exception. Yanovski and Yanovski review the pharmacotherapy of obesity and briefly cover behavior aspects of weight management and clinical trials of investigational weight-loss agents.

The authors cite the evidence-based obesity treatment guideline from the National Institutes of Health when deciding how aggressively to manage overweight patients. Those with a body mass index (BMI) greater than 25 are typically targeted with behavior modification interventions. When the BMI is greater than 30, or if there is any obesity-related disease and a BMI greater than 27, pharmacotherapy is recommended. Very obese patients (BMI greater than 40, or an obesity-related disease and BMI greater than 35) who have failed previous attempts at weight loss may be candidates for bariatric surgery.

Pharmacotherapy for weight loss falls primarily into two categories, appetite suppressants and agents that decrease food absorption (see the accompanying table on page 1676). Noradrenergic agents (e.g., phentermine) are approved by the U.S. Food and Drug Administration (FDA) for short-term adjunctive treatment of obesity. Benzphetamine and phendimetrazine are thought to have somewhat higher abuse potential than the other noradrenergic agents.

Medications Approved for the Treatment of Obesity*

View Table

Medications Approved for the Treatment of Obesity*

Agent Mechanism of action Dosage Wholesale Price DEA schedule† Potential drug interactions Contraindications‡

Benzphetamine (Didrex)

Noradrenergic

25 to 50 mg one to three times per day

$1.19 to $2.38 per day

III

MAOIs, guanethidine, CNS stimulants, alcohol, sibutramine, tricyclic antidepressants

Hypertension, advanced cardiovascular disease, hyperthyroidism, glaucoma, agitated states, history of drug abuse

Phendimetrazine (Bontril)

Noradrenergic

17.5 to 70 mg two to three times per day or 105 mg sustained-release per day

$1.20 to $5.25 per day

III

Same as above

Same as above

Phentermine (Adipex-P)

Noradrenergic

18.75 to 37.5 mg per day

$0.67 to $1.60 per day

IV

Same as above

Same as above

Phentermine resin (Ionamin)

Noradrenergic

15 to 30 mg per day

$1.75 to $2.01 per day

IV

Same as above

Same as above

Diethylpropion (Tenuate)

Noradrenergic

25 mg three times per day or 75 mg sustained-release per day

$1.27 to $1.52 per day

IV

Same as above

Same as above

Sibutramine (Meridia)

Mixed noradrenergic and serotonergic

5 to 15 mg per day

$2.98 to $3.68 per day

IV

SSRIs, MAOIs, centrally active anorexiants, sumatriptan, dihydroergotamine, dextromethorphan, meperidine, pentazocine, fentanyl, lithium, tryptophan

Uncontrolled hypertension, severe renal impairment, severe hepatic dysfunction, narrow-angle glaucoma, or history of substance abuse, coronary artery disease, congestive heart failure, arrhythmias, or stroke

Orlistat (Xenical)

Lipase inhibitor

120 mg three times per day with or within one hour after fat-containing meals, plus a daily multivitamin

$3.56 per day

Not scheduled

Cyclosporine

Chronic malabsorption syndromes, cholestasis

DEA = Drug Enforcement Agency; MAOIs = monoamine oxidase inhibitors; CNS = central nervous system; SSRIs = selective serotonin reuptake inhibitors.

*— Only sibutramine and orlistat are approved for long-term use; the others are approved only for short-term use (i.e., a few weeks).

†— Medications on DEA schedule III are associated with a higher risk of abuse than those on schedule IV, for which the potential for abuse is considered low.

‡— If there is a sustained increase in blood pressure or pulse rate, either a reduction in the dose or discontinuation should be considered.

Adapted with permission from Yanovski SZ, Yanovski JA. Obesity. N Engl J Med 2002;346:593.

Agents that raise serotonin levels have been used in weight loss management but have serious side effects (e.g., fenfluramine, which was withdrawn from the market because it caused valvular heart disease) or lack long-term efficacy (e.g., fluoxetine and other selective serotonin reuptake inhibitors).

Sibutramine is a mixed noradrenergic-serotonergic agent that has not been associated with valvular heart disease and has controlled studies showing long-term efficacy. Discontinuation because of increased blood pressure occurred in only 5 percent of users in large trials. More common side effects included dry mouth, constipation, headache, and insomnia.

The only FDA-approved medication to decrease food absorption is orlistat. Malabsorption of dietary fat is responsible for the beneficial weight loss effect of this agent and the typical side effects (flatulence, and increased stool frequency and urgency).

All of the agents presently available cause similar, moderate degrees of weight loss. The authors note that the choice for an individual patient is largely empiric, and that long-term use of medication is likely to be necessary for maintenance of any successful weight loss.

BILL ZEPF, M.D.

Yanovski  SZ, Yanovski  JA.  Obesity.  N Engl J Med.  February  21,  2002;346:591–602.


Copyright © 2002 by the American Academy of Family Physicians.
This content is owned by the AAFP. A person viewing it online may make one printout of the material and may use that printout only for his or her personal, non-commercial reference. This material may not otherwise be downloaded, copied, printed, stored, transmitted or reproduced in any medium, whether now known or later invented, except as authorized in writing by the AAFP. Contact afpserv@aafp.org for copyright questions and/or permission requests.

Want to use this article elsewhere? Get Permissions


Article Tools


AFP Resources


Stay Connected