...Phentermine-RX - Eating Strategies!

Prescription Weight Loss Medications

No review of dieting would be complete without discussing the current pharmacological options available. First of all, there are no "magic pills" that are going to solve the dieting dilemma. The use of appetite suppressants may help individuals over the short term, however, they are not a substitute for developing healthy eating habits over the long term. Therefore use of pharmacotherapy for weight reduction should not commence without an adjunctive diet, behavioral modifications and an exercise program.

The Weight Loss Practice Survey, sponsored by the FDA and The National Heart, Lung and Blood Institute, found that 5 percent of women and 2 percent of men trying to lose weight use diet pills. The majority of these diet pills are over-the-counter (OTC) medications, containing the active ingredient phenylpropanolamine (PPA), such as, Dexatrim and Acutrim. " Using diet pills containing PPA will not make a big difference in the rate of weight loss, even the best studies show only about a half pound or greater weight loss, per week, using OTC pills, combined with diet and exercise," states, Robert Sherman of the FDA’s Office of OTC Drug Evaluation. The problem with these medications is although they suppress an individual’s appetite early in treatment the medication’s effects are usually short lived. After approximately six weeks or less most individuals become acclimated to the medication and the appetite suppression qualities are minimized.

Currently, there are several prescription medications used for the treatment or management of obesity. These medications include:

Lipase Inhibitors (Xenical)
Sympathomimetic Amines (Adipex P, Phentermine, Fastin, Ionamin, etc.)
Neurotransmitter Re-uptake Inhibitors (Meridia)
Amphetamines (Dexedrine)

Lipase Inhibitor, Xenical (orlistat) is a new weight control medication recently approved by the FDA. Distinct from other medications that effect neurotransmitters to stimulate the brain to suppress appetite. Xenical uses a fat blocking mode of action that works non-systemically in the gastrointestinal tract. Dietary fats are large molecules that must be broken down by enzymes, called lipases, before they can be absorbed into the bloodstream. Xenical interferes with these lipases by forming covalent bonds with the them in the stomach and small intestine, this essentially inactivates the enzymes so they are no longer available to hydrolyze dietary fat into an absorbable state. Thus, allowing for some 30 percent of dietary fats to pass through the gastrointestinal tract unchanged.

*Xenical® works here, covalently bondings to the pancreatic lipases

Clinical studies indicate, in the first year, that individuals treated with Xenical (120 mg per dose, three times per day) and a low calorie diet lost approximately two-thirds more weight than those treated with the same diet and a placebo. In the second year, individuals treated with Xenical and a weight maintenance diet were two times as likely to keep the weight off as individuals on the same diet and a placebo.

"This study demonstrates that partial inhibition of fat absorption in obese subjects can produce sustained weight loss," the authors conclude. "Subjects treated with Orlistat plus a mildly controlled-energy diet lost significantly more weight than those treated with placebo plus diet even though all subjects received a high standard of care and similar dietary counseling… These observations collectively suggest Orlistat may be a useful adjunct to dietary intervention in producing and maintaining weight loss over two years." Journal of the American Medical Association (JAMA. 1999;281:235-245)

Side effects associated with Xenical include:
Cardiovascular: none
Central Nervous System: none
Gastrointestinal: Secondary to the mechanism of action, blocking dietary fats, most individuals experience some changes in bowel habits. These changes may include gas with discharge, an increase in the frequency of bowel movements, fatty or oily stools, and sometimes incontinence.
Allergic: none
Endocrine: none

Contraindications to the use of Xenical include: chronic malabsorption syndromes, cholestasis, individuals with known hypersensitivity to orlistat or any of the active ingredients in Xenical.

Sympathomimetic Amines, such as, phentermine hydrochloride continue to be commonly prescribed for weight loss. Although there are concerns about the widespread and indiscriminate use of the medications, most physicians concur the potential for abuse and dependency are mild as compared to the amphetamines. Phentermine is an anorectic medication (decrease an individual’s appetite) with pharmacologic activity similar to the amphetamines.

Clinical trials suggest that adult obese individuals, instructed in dietary management and treated with phentermine, lose more weight than those treated with a placebo and diet. The amount of weight loss varies from trial to trial and appears to be associated variables other than the medication. Physician-investigators, the population treated and the diet prescribed all seemed to have an impact on the amount of weight reduction. Phentermine is indicated in the treatment of obesity as a short- term adjunct to diet modification and an exercise program.

Side affects associated with phentermine include:
Cardiovascular: Palpitation, Tachycardia, and elevation of blood pressure.
Central Nervous System: Overstimulation, restlessness, Dizziness, insomnia,
euphoria, dyshoria, tremor, headache; rarely psychotic episodes at recommended doses.
Gastrointestinal: Dryness of the mouth, unpleasant taste, diarrhea, constipation, other gastrointestinal disturbances.
Allergic: Urticaria.
Endocrine: Impotence changes in libido.

Contraindications of to the use of Phentermine include: advanced ateriosclerosis, symptomatic cardiovascular disease, moderate to severe hypertension, hyperthyroidism, known hypersensitivity or idiosyncrasy to the sympathomimetic amines, glaucoma, agitated states, patients with a history of drug abuse, during or within 14 days following the administration of monoamine oxidase inhibitors, (MAO), etc.

Neurotransmitter re-uptake inhibitors, such as Meridia (sibutramine hydrochloride monohydrate) generates a therapeutic affect by inhibiting the re-uptake of norepinephrine, serotonine and dopamine in the synaptic cleft of the brain. This subsequently results in an increase in these neurotransmitters; an increase in serotonine produces the early sensation of feeling "full." Re-uptake inhibitors are not true appetite suppressants. Individuals continue to have the desire to eat but they feel full or content earlier, therefore, they eat less. In clinical trials, individuals treated with Meridia while on a reduced caloric diet, showed a significant weight reduction. In one twelve month study, the average weight loss in patients taking 10mg of sibutamine daily, was approximately 10 lbs. Those individuals taking 15mg daily averaged 14 lbs. in the same time frame. The average weight loss in individuals who were treated with diet alone lost only an average of 3.5 lbs. Conversely, of those individuals on a given dose of Meridia who did not lose at least 4 lbs. in the first four weeks of therapy, approximately 80 percent of those individuals did not go on to achieve significant weight loss.

Side affects associated with Meridia include:
Cardiovascular: tachycardia (increased pulse rate up to 10 beats per minute),
increase in blood pressure (15mg Hg in systolic, 10mg Hg in diastolic reported in some individuals)
Central Nervous System: dry mouth, headache, insomnia, dizziness, anxiety, seizures, mydriasis
Gastrointestinal: nausea constipation heartburn
Allergic: none
Endocrine: none

Contraindications to the use of Meridia include: those receiving monoamine oxidase inhibitors (MAO’s) or other centrally acting appetite suppressants, patients with a history of coronary artery disease, congestive heart failure, arrhythmias, stroke, anorexic nervosa, uncontrolable hypertension, severe renal impairment, severe hepatic dysfunction, glaucoma, patients with known hypersensitivity to sibutamine or any of the active ingredients in Meridia, etc.

Meridia is a controlled substance, schedule IV, physicians should evaluate patients for a history of drug abuse and follow these patients closely, observing them for signs of abuse (tolerance, incremental doses, drug seeking behavior, etc.).

Amphetamines, such as, Dexedrine are no longer in vogue for weight reduction therapy. Most physicians have stopped prescribing amphetamines secondary to their high abuse potential and the risk of individuals becoming psycho-physically dependent on these medications.

Two new medications may hold promise for weight reduction in the future:

Cholecystokinin is a neurotransmitter in the brain that produces the feeling of satiety. If a medication can increase the effect of this naturally occurring brain chemical, individuals would feel full quicker and presumably eat less. Several pharmaceutical companies are investigating cholecystokinin-boosting agents, however, this potential medication is in the early trials so FDA approval is a few years away.

Leptin, is another neurotransmitter known to suppress appetite. Currently, biotechnology is capable of producing the equivalent of the neurotransmitters in mass quantities. Early studies have shown mild weight loss associated with the medication. However, FFD approval is at least a year or more in the future.

Of all the above listed medications, Xenical should prove to be the most beneficial and effective medication in the long-term treatment of obesity. Xenical’s ability to block the digestion of some 30 percent of dietary fats represents a significant decrease in the caloric intake for some individuals. Since Xenical works non-systemically in the gastrointestinal tract side effects are minimal. In fact, in therapeutic studies some 97 percent of orlistat was found to be excreted into the feces. This is reassuring, especially following the recent side effects associated with fen/phen (valvular heart disease, pulmonary hypertension). Additionally, with Xenical there are no complications involving tolerance or dependency as the case with the anorectic medications. Therefore, Xenical may be prescribed safely for longer periods of time.