Sibutramine is known as a satiety enhancer. It is used as part of a weight management program, along with a calorie-reduced diet, to help people lose weight. It works in the brain by affecting certain chemicals that control your appetite, and helps you eat less by making you feel full sooner. It may also increase the way your body uses energy (thermogenesis).

This medication should only be used by people who have not been successful in losing sufficient weight on a low calorie diet alone, and who have a body mass index (BMI) of 30 or higher, or by people with a BMI of 27 or higher who also have other conditions such as high blood pressure, type 2 diabetes, or high cholesterol.

BMI is calculated by dividing your body weight in kilograms by the square of your height in metres. For example, if you weigh 150 lb. (68 kg) and are 5'8" (1.73 m) tall, divide 68 by (1.73 × 1.73), or 2.99. The result is a BMI of 22.74 kg/m².

Your doctor may have suggested this medication for conditions other than the ones listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

The usual adult dose of sibutramine is 10 mg once daily, taken in the morning. The doctor may increase or decrease the dose as needed, but the daily dose does not usually exceed 15 mg. Children's doses must be individually determined by the doctor. Sibutramine may be taken with or without food as directed by your doctor.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are using the medication without consulting your doctor.

It is important to use this medication exactly as prescribed by your doctor. It is also important to follow the diet as recommended by your health professional very closely. If you miss a prescribed dose of this medication and you remember within two or three hours, take the medication as soon as you remember. If you do not remember until later, skip the missed dose and resume your prescribed schedule. Do not take a double dose to make up for a missed one.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

Store this medication in a dry place and away from heat and light.

Meridia® is available in two different strengths.

10 mg: Each blue-and-white capsule, marked "MERIDIA" on the cap and "10" on the body, contains 10 mg of sibutramine. Nonmedicinal ingredients: colloidal silicon dioxide, lactose, magnesium stearate, and microcrystalline cellulose; capsule shell: FD&C Blue No. 2, gelatin, silicon dioxide, sodium lauryl sulfate, and titanium dioxide.

15 mg: Each yellow-and-white capsule, marked "MERIDIA" on the cap and "15" on the body, contains 15 mg of sibutramine. Nonmedicinal ingredients: colloidal silicon dioxide, lactose, magnesium stearate, and microcrystalline cellulose; capsule shell: D&C Yellow No. 10, gelatin, silicon dioxide, sodium lauryl sulfate, and titanium dioxide.

Sibutramine should not be used by anyone who:

• is allergic to sibutramine or any of the ingredients in this medication
• is taking (or has taken within the last 14 days) any of the medications known as MAO inhibitors (e.g., phenelzine, selegeline, tranylcypromine, moclobemide)
• has a history of or is currently suffering from anorexia nervosa or bulimia nervosa
• is taking other weight management medications that act on chemicals of the brain (e.g., phentermine)
• has high blood pressure that is not properly controlled
• has had coronary artery disease, congestive heart failure, abnormal heart rhythms, stroke, or TIA (transient ischemic attack, or "mini-stroke")
• has a psychiatric illness
• is taking (or has taken within the last 14 days) medications for the treatment of psychiatric illness (e.g., antidepressants, antipsychotics, St. John's wort)
• is taking or has taken the antidepressant fluoxetine in the last five weeks
• is pregnant or planning to become pregnant
• is breast-feeding
• develops seizures or convulsions while taking the medication
• has kidney disease or severe liver disease

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your health professional. They may be able to help you to deal with some of the effects.

The following side effects may go away as your body becomes used to the medication; check with your doctor if they continue or become bothersome.

More common
• constipation
• dry mouth
• headache

Less common
• abdominal pain
• anxiety
• back pain
• diarrhea
• dizziness
• drowsiness
• increase or decrease in appetite
• increased blood pressure
• increased sweating
• increased thirst
• joint pain
• nervousness
• upset stomach
• stuffy or runny nose
• trouble sleeping
• unusual warmth or flushing of skin

Call your doctor as soon as possible if any of the following side effects occur:

• blackouts or confusion
• bruising or red spots or patches on skin
• chest pain
• depression
• eye pain or bleeding
• fast, irregular or pounding heartbeat
• nausea and vomiting
• seizures
• severe headache
• shortness of breath
• skin rash
• swelling of body or feet and ankles

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Bleeding disorders: In rare cases, sibutramine can cause abnormal bleeding. It should be used with caution by people who use medications that affect blood clotting and by people who have a history of bleeding disorders.

Blood pressure: Sibutramine can cause blood pressure to increase, worsening heart disease and increasing the risk of stroke. Make sure that you see your doctor for regular blood pressure checks while taking sibutramine.

Breast-feeding: It is not known whether sibutramine passes into breast milk. It is not recommended while nursing.

Children: The safety and effectiveness of sibutramine have not been established for children under 18 years of age. It is not recommended for use by this age group.

Depression: Sibutramine should be used with caution by people who have a history of depression or currently suffer from depression.

Eye disorders: Sibutramine can cause long-lasting abnormal dilation of the pupil of the eye. It should be used with caution by people with narrow-angle glaucoma.

Gallstones: Weight loss can cause gallstone formation or make a pre-existing gallstone condition worse.

Pregnancy: The safety and effectiveness of sibutramine have not been established for pregnant women. It is not recommended for use during pregnancy. Women should use reliable birth control while taking this medication. Talk to your doctor if you become pregnant, or if you plan to become pregnant, while taking this medication.

Seizures: In rare cases, sibutramine can cause seizures. It should be used with caution by people who have a history of epileptic seizures. Anyone who develops seizures should stop using sibutramine and consult their doctor.

Seniors: The safety and effectiveness of sibutramine have not been established for people over 65 years of age. It is not recommended for use by this age group.

The following medications may affect how sibutramine works or increase the risk of side effects:

• certain opioid medications (e.g., meperidine, pentazocine, fentanyl)
• erythromycin
• fentanyl
• ketoconazole
• levodopa
• lithium
• MAO inhibitors (e.g., dihydroergotamine, moclobemide, phenelzine, selegeline, tranylcypromine)
• meperidine
• migraine medications (e.g., rizatriptan, sumatriptan, zolmitriptan, dihydroergotamine)
• other weight management medications (e.g., mazindol, phentermine)
• over-the-counter cold remedies such as decongestants (e.g., pseudoephedrine) and cough suppressants (dextromethorphan)
• pentazocine
• SSRI antidepressants (e.g., fluoxetine, sertraline, citalopram, fluvoxamine, paroxetine)
• St. John's wort
• tricyclic antidepressants (e.g., amitriptyline)
• tryptophan

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. In many cases, interactions are intended or are managed by close monitoring. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.