Many individuals struggle with weight loss, and medications may be able to help. Obese patients who have a body mass index of 30 or greater, or 27 or greater with risk factors, are eligible for prescription weight-loss aids. These medications are designed to increase weight loss when diet and exercise are not sufficient. You should speak with a physician if you wish to start on a prescription weight-loss drug. Your physician can perform a proper assessment and choose the best one for you.
Action
There are two classes of prescription medications used for weight loss: anorexiants and lipase inhibitors. The anorexiants available in the United States are phentermine, or the brand name Adipex-P, diethylpropion, or the brand name Tenuate, and phendimetrazine, or the brand name Bontril. These medications work in the brain by stimulating a gland called the hypothalamus. This results in increased breakdown of two chemicals, norepinephrine and dopamine, and decreases the appetite. The only lipase inhibitor available is orlistat, or Xenical. It works by blocking stomach and pancreatic lipases, which are enzymes involved in the breakdown of fat. The body is unable to absorb fats and eliminates them from the body.
Side Effects
The anorexiants may produce dizziness, restlessness, insomnia, increased blood pressure, changes in sex drive and heart palpitations. Gastrointestinal side effects include an unpleasant taste in the mouth, dry mouth, upset stomach, nausea and vomiting. Orlistat produces many gastrointestinal side effects, including oily spotting, oily stools, gas with discharge and increased bowel movements; at least one gastrointestinal complaint is reported in about 80 percent of patients, according to "Pharmacotherapy: A Pathophysiologic Approach." About 38 percent of individuals may develop an upper respiratory infection.
Prevention/Solution
Patients should not take more than the prescribed dose to avoid worsening of side effects. Most side effects diminish with continued use of the medication. To avoid insomnia with the anorexiants, do not the medication in the evening. Do not drive or engage in activities that require alertness if you develop dizziness.
Orlistat side effects are most common during the first two months of therapy. You should limit the amount of fat you consume to avoid severe gastrointestinal side effects.
Warnings
The anorexiants are associated with primary pulmonary hypertension, which is an abnormal increase in the blood pressure in the arteries of the lungs. Although this disease is rare, it may be fatal. Patients with diabetes may require a decrease in insulin or oral antidiabetics before starting the weight loss drug.
The "Drug Information Handbook" explains that orlistat reduces the absorption of beta carotene and fat-soluble vitamins, which include A, D, E and K. Ask your doctor about a multivitamin containing these vitamins to avoid a deficiency.
Contraindications
Anorexiants are contraindicated in patients with advanced hardening of the arteries, severe high blood pressure, hyperthyroidism, glaucoma and history of high blood pressure. "Pharmacotherapy" explains that patients cannot take an anorexiant during or within 14 days after taking a monoamine oxidase inhibitor, such as selegiline, phenelzine and hydralazine.
Orlistat is not recommended in patients with chronic malabsorption syndrome and cholestasis, in which the bile cannot flow from the liver to the stomach.
References
- "Pharmacotherapy: A Pathophysiologic Approach"; Joseph T. Dipiro, Robert L. Talbert, et al.; 2008
- "Drug Information Handbook"; Charles F. Lacy, Lora L. Armstrong, et al.; 2009
Member Comments