Weight Loss Drugs Prescription and OTC »
Taking a weight loss drug may not result in weight loss by itself. But using diet pills can help an overweight person stay on a diet because nearly all of these medications work on suppressing appetite. "Feeling full" is believed to be related to a number of biochemical processes in the body. Signals to indicate fullness come from fat cells and the gastrointestinal tract; these converge with signals in the central nervous system. Appetite suppressants target a couple of key neurotransmitters in this process: serotonin and norepinephrine. Increased levels of serotonin result in a feeling of fullness. Increasing norepinephrine levels stimulate the central nervous system, decreasing appetite. Only one drug among the weight loss medications works in a different way. Orlistat (Xenical, Alli) works in the gastrointestinal tract to prevent absorption of about a third of ingested fat.
|
|
XENICAL
(orlistat)
XENICAL (orlistat) is a gastrointestinal lipase inhibitor for obesity management that acts by inhibiting the absorption of dietary fats.
Orlistat is (S)-2-formylamino-4-methyl-pentanoic acid
(S)-1-[[(2S, 3S)-3-hexyl-4-oxo-2-oxetanyl] methyl]dodecyl ester. Its empirical
formula is C29H53NO5, and its molecular weight
is 495.7. It is a single diastereomeric molecule that contains four chiral
centers, with a negative optical rotation in ethanol at 529 nm. The structure
is:
 |
Orlistat is a white to off-white crystalline powder. Orlistat is practically insoluble in water, freely soluble in chloroform, and very soluble in methanol and ethanol. Orlistat has no pKa within the physiological pH range.
XENICAL is available for oral administration as a dark-blue or turquoise hard-gelatin capsule. The dark blue capsule is imprinted with light blue and the turquoise capsule is imprinted with black. Each capsule contains a pellet formulation consisting of 120 mg of the active ingredient, orlistat, as well as the inactive ingredients microcrystalline cellulose, sodium starch glycolate, sodium lauryl sulfate, povidone, and talc. The dark blue capsule shell contains gelatin, titanium dioxide, and FD&C Blue No. 1, with printing of pharmaceutical glaze NF, titanium dioxide, and FD&C Blue No. 1 aluminum lake. The turquoise capsule shell contains gelatin, titanium dioxide, and FD&C Blue No. 2 with black printing ink containing pharmaceutical grade shellac, dehydrated alcohol, isopropyl alcohol, butyl alcohol, propylene glycol, strong ammonium solution, potassium hydroxide and black iron oxide.
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Stop taking orlistat and call your doctor at once if you have severe pain in your upper stomach spreading to your back, nausea and vomiting, and a fast heart rate. These could be signs of pancreatitis.
The following side effects occur commonly with the use of orlistat. They are the natural effects of orlistat's fat-blocking action and are actually signs that the medication is...
Read All Potential Side Effects and See Pictures of Xenical »
Before taking orlistat, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: certain digestive problem (chronic malabsorption syndrome), certain gall bladder problem (cholestasis).
Before using this medication, tell your doctor or pharmacist your medical history, especially of: underactive thyroid (hypothyroidism), kidney stones/problems (e.g., calcium oxalate kidney stones, hyperoxaluria), certain eating disorders (anorexia...
Last reviewed on RxList: 2/7/2012
This monograph has been modified to include the generic and brand name in many instances.
Here is a collection of user reviews for the medication Xenical sorted by most helpful.
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
Find out what women really need.
Copyright © 2012 by WebMD, LLC.
RxList does not provide medical advice, diagnosis or treatment. See additional information.
Updated & New