Orlistat, sometimes called tetrahydrolipstatin, is a weight-loss medication that is classified as a lipase inhibitor. Lipase inhibitors prevent certain enzymes, called lipases, from digesting complex fats in the body. The body then removes these fats in their complete form, rather than breaking them down and allowing them to be absorbed. Unlike many medications that have many potential dosages based on the condition of the person taking them, a single orlistat dosage is used for most people. Slight differences in the dosing regimen do exist, however, which can influence how often it is taken.
Normally, the prescription orlistat dosage consists of 120 milligrams (mg), taken with any meal that has fat. It may be taken up to three times per day, once with each meal, within an hour of eating. Missing a meal, or eating a meal without fat, means that a dose may be skipped without adverse consequences.
The use of the 120 mg orlistat dosage as the prescribed amount has its roots in scientific evidence. Research performed by GlaxoSmithKline, one of the manufacturers of this medication, has shown that higher doses do not provide any additional benefits. This amount of the medication removes almost a third of the fat from a meal.
In addition to being prescribed, this weight-loss medication may also be purchased as an over-the-counter (OTC)formulation, but in a different dose. Usually, an orlistat dosage of 60 mg is used when the medication is taken without a prescription. Like the prescription version of this rug, the OTC form is taken around mealtime, for a maximum of three times each day.
Most people taking orlistat for weight loss do not develop severe side effects, though there are exceptions. Even therapeutic doses of this drug have some potential risks. Vitamin depletion is the most common of these, because some vitamins that normally absorb into the body's fat cells may be excreted with this drug. Taking vitamin supplements may help to prevent this phenomenon.
Dosing of orlistat does not have to be adjusted for conditions affecting the renal system, or kidneys, as it does not leave the body through the urine. Renal injury may sometimes result from the use of this drug, however, as it can cause harmful chemicals called oxalates to shift from the gastrointestinal (GI) tract to the kidneys. Occasionally, damage to the liver may result from taking orlistat as well, although it is not metabolized by this organ.
