Obesity (Weight Loss) (cont.)
What is the role of medication in the treatment of obesity?
Medication treatment of obesity should be used only in patients who have
health risks related to obesity. Medications should be used in patients with a
BMI greater than 30 or in those with a BMI of greater than 27 who have other
medical conditions (such as high blood pressure, diabetes, high blood
cholesterol) that put them at risk for developing heart disease. Medications
should not be used for cosmetic reasons.
Like diet and exercise, the goal of medication treatment has to be realistic.
With successful medication treatment, one can expect an initial weight loss of
at least 5 pounds during the first month of treatment, and a total weight loss
of 10%-15% of the initial body weight. It is also important to remember that
these medications only work when they are taken. When they are discontinued,
weight gain can occur.
The first class (category) of medication used for weight control cause
symptoms that mimic the sympathetic nervous system. They cause the body to feel
"under stress" or " nervous." As a result, the major side effect of this
class of medication is high blood pressure. This class of medication includes
sibutramine (Meridia) and phentermine (Fastin, Adipex P). These medications also
decrease appetite and create a sensation of fullness. Hunger and fullness
(satiety) are regulated by brain chemicals called neurotransmitters. Examples of
neurotransmitters include serotonin, norepinephrine, and dopamine. Anti-obesity
medications that suppress appetite do so by increasing the level of these
neurotransmitters at the junction (called synapse) between nerve endings in the
brain.
Phentermine
Phentermine (Fastin, Adipex P)
- (the other half of fen/phen) suppresses appetite by causing a
release of norepinephrine by the cells. Phentermine alone is still available for
treatment of obesity, but only on a short-term basis (a few weeks). The common
side effects of phentermine include headache, insomnia, irritability and
nervousness. Fenfluramine (the fen of fen/phen) and dexfenfluramine (Redux)
suppress appetite mainly by increasing release of serotonin by the cells.
Both fenfluramine and dexfenfluramine were withdrawn from the
market in September 1997 because of association of these two medications with pulmonary hypertension (a rare but serious disease of the arteries in the
lungs), and association of fen/phen with damage to the heart valves. Since the
withdrawal of fenfluramine, some have suggested combining phentermine with
fluoxetine (Prozac) - a combination that has been referred to as phen/pro.
However, no clinical trials have been conducted to confirm the safety and
effectiveness of this combination. Therefore, this combination is not an
accepted treatment for obesity.
Sibutramine (Meridia)
Sibutramine (Meridia) suppresses appetite by increasing the amount of
neurotransmitters serotonin and norepinephrine in the brain synapses. Unlike
fenfluramine and dexfenfluramine, sibutramine does not increase release of these
neurotransmitters from the cells. Instead, sibutramine inhibits the re-uptake of
these neurotransmitters by the nerve cells. Therefore, the action of sibutramine
is similar to that of anti-depressants that inhibit re-uptake of serotonin such
as fluoxetine (Prozac), a medication that has been used for years without known
association with pulmonary hypertension or heart valve damage.
In December 1997, the United States Food and Drug Administration (FDA)
approved sibutramine (Meridia) to treat obesity (both in attaining and in
maintaining weight loss). According to FDA guidelines, Meridia should be
considered only for patients with a BMI of 30 or higher, or for those with a BMI
of 27 or higher who also have other conditions (such as high blood pressure,
diabetes mellitus, sleep apnea) that can improve with weight loss. Meridia
should be accompanied by regular exercise and a reduced-calorie diet.
Meridia is available in 5, 10, and 15mg capsules. The recommended starting
dose is one 10 mg capsule per day. The dose of Meridia can be increased if
weight loss is inadequate. Meridia should always be prescribed by doctors
familiar with the patients' medical condition, and familiar with the use and
side effects of the medicine.
In clinical trials involving 6,000 individuals, Meridia produced
statistically significantly more weight loss when compared to placebo (sugar
pill). Generally, weight loss achieved with Meridia is modest. On average,
patients treated with Meridia lost 5% to 10% of initial weight at various dosage
levels. In two 12-month studies, maximal weight loss was achieved by six months,
and statistically significant weight loss was maintained over 12 months.
Thus far, there are no reported increases in pulmonary hypertension or heart
valve damage associated with the use of Meridia. Like any
medication, however, close monitoring will be necessary to determine the drug's
long-term safety and effectiveness. Certain side effects may not become apparent
until months to years after release.
The known side effects of Meridia are mild and transient. They include dry
mouth, headache, constipation,
and insomnia. Meridia also causes a small increase in average blood pressure and
heart rate. But in some individuals, the increase in blood pressure can be more
pronounced. Therefore, patients on Meridia should have regular monitoring of
their blood pressure. Meridia should not be used in patients with uncontrolled
high blood pressure, history of stroke, coronary heart disease, and congestive
heart failure.
Orlistat (Xenical,
alli)
The next class (category) of drugs changes the metabolism of fat.
Orlistat (Xenical, alli) is the only drug of this category that is U.S. FDA approved. This is a class of anti-obesity drugs called lipase inhibitors, or fat blockers. Fat from food can only be absorbed into the body after being broken up (a process called digestion) by digestive enzymes called lipases in the intestines. By inhibiting the action of lipase enzymes, orlistat prevents the intestinal absorption of fat by 30%. Drugs in this class do not affect brain chemistry. Theoretically, orlistat also should have minimal or no systemic side effects (side effects in other parts of the body) because the major locale of action is inside the gut lumen and very little of the drug is absorbed.
The U.S. Food and Drug Administration approved orlistat capsules, branded as alli, as an over-the-counter (OTC) treatment for overweight adults in February 2007. The drug had previously been approved in 1999 as a prescription weight loss aid, whose brand name is Xenical). The OTC preparation has a lower dosage than prescription Xenical.
Orlistat is recommended only for people 18 years of age and over in combination with a diet and exercise regimen. People who have difficulties with the absorption of food or who are not overweight should not take orlistat. Overweight is defined by the U.S. National Institutes of Health as having a body mass index (BMI) of 27 or greater.
Orlistat can be taken up to three times a day, with each fat-containing meal. The drug may be taken during the meal or up to one hour after the meal. If the meal is missed or is very low in fat content, the medications should not be taken.
The most common side effects of orlistat are changes in bowel habits. These include gas, the urgent need to have a bowel movement, oily bowel movements, oily discharge or spotting with bowel movements, an increased frequency of bowel movements, and the inability to control bowel movements. Women may also notice irregularities in the
menstrual cycle while taking orlistat. Side effects are most common in the first few weeks after beginning to take orlistat. In some people the side effects persist for as long as they are taking the drug.
People with diabetes, thyroid conditions, who have received an organ transplant, or who are taking prescription medications that affect blood clotting should check with their physician before using OTC orlistat (alli), since drug interactions with certain medications are possible.
A long-term decrease in fat absorption can cause deficiency of fat-soluble vitamins (such as vitamins A, D, E, K). Therefore, patients on orlistat should receive adequate
vitamin supplementation.
Next: What about herbal fen/phen? »
- orlistat, Xenical, alli - Read about orlistat (Xenical, Alli) the weight loss drug. Alli is available over the counter and Xenical is available by prescription only. Side effects, precautions, and drug interaction information is included as well.
- C-Reactive Protein (CRP Test) - Learn about your heart disease or stroke risk and how the c-reactive protein test(CRP) may be a marker of the inflammation of arteries. Risk f
- High Blood Pressure - Learn about high blood pressure symptoms like headache, dizziness, shortness of breath, blurred vision and more. Causes, and normal blood pressure information is included.
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