Sibutramine (si-BYOO-tra-meen) is used together with a reduced-calorie diet to help you lose weight and to help keep the lost weight from returning. Sibutramine is thought to work by increasing the activity of certain chemicals, called norepinephrine and serotonin, in the brain. This medicine is approved for use only in people who are very overweight.

This medicine is available only with your doctor's prescription, in the following dosage form:

Oral

• Capsules (U.S.)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For sibutramine, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to sibutramine. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Sibutramine has not been studied in pregnant women. However, studies in animals have shown that sibutramine causes birth defects when used in doses many times higher than the usual human dose. Before taking this medicine, make sure your doctor knows if you are pregnant or if you may become pregnant.

Breast-feeding—It is not known whether sibutramine passes into breast milk. Although most medicines pass into breast milk in small amounts, many of them may be used safely while breast-feeding. A mother who is taking this medicine and who wishes to breast-feed should discuss this with her doctor.

Children—Studies on this medicine have been done only in adult patients, and there is no specific information comparing use of sibutramine in children with use in other age groups.

Older adults—Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults. Although there is no specific information comparing use of sibutramine in the elderly with use in other age groups, this medicine is not expected to cause different side effects or problems in older people than it does in younger adults.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking sibutramine, it is especially important that your health care professional know if you are taking any of the following:

• Appetite suppressants, other (benzphetamine [e.g., Didrex], diethylpropion [e.g., Tenuate], mazindol [e.g., Sanorex], phendimetrazine [e.g., Phendiet], phentermine [e.g., Ionamin])—The effects of using sibutramine in combination with another appetite suppressant are not known

• Bromocriptine (e.g., Parlodel) or

• Buspirone (e.g., BuSpar) or

• Certain tricyclic antidepressants (amitriptyline [e.g., Elavil], clomipramine [e.g., Anafranil], imipramine [e.g., Tofranil]) or

• Dextromethorphan (cough medicine) or

• Levodopa (e.g., Sinemet) or

• Lithium (e.g., Eskalith) or

• Meperidine (e.g., Demerol) or

• Nefazodone (e.g., Serzone) or

• Pentazocine (e.g., Talwin) or

• Selective serotonin reuptake inhibitors (citalopram [e.g., Celexa], fluoxetine [e.g., Prozac], fluvoxamine [e.g., Luvox], paroxetine [e.g., Paxil], sertraline [e.g., Zoloft]) or

• Street drugs (LSD, MDMA [e.g., ecstasy], marijuana) or

• Sumatriptan (e.g., Imitrex) or

• Tramadol (e.g., Ultram) or

• Trazodone (e.g., Desyrel) or

• Tryptophan or

• Venlafaxine (e.g., Effexor)—Using these medicines with sibutramine may increase the chance of developing a rare, but very serious, unwanted effect known as the serotonin syndrome. Symptoms of this syndrome include confusion, diarrhea, fever, poor coordination, restlessness, shivering, sweating, talking or acting with excitement you cannot control, trembling or shaking, or twitching. If you develop these symptoms, contact your doctor as soon as possible

• Moclobemide (e.g., Manerex)—Taking moclobemide and sibutramine together or less than 3 days apart may increase the chance of developing serious unwanted effects, including the serotonin syndrome, and is not recommended

• Monoamine oxidase (MAO) inhibitor activity (isocarboxazid [e.g., Marplan], phenelzine [e.g., Nardil], procarbazine [e.g., Matulane], selegiline [e.g., Eldepryl], tranylcypromine [e.g., Parnate])— Do not take sibutramine while you are taking or within 2 weeks of taking an MAO inhibitor, and do not take an MAO inhibitor within 2 weeks of taking sibutramine . If you do, you may develop severe seizures, extremely high blood pressure, or the serotonin syndrome. Allow at least 2 weeks to pass between taking one of these medicines (sibutramine or an MAO inhibitor) and taking the other

Other medical problems—The presence of other medical problems may affect the use of sibutramine. Make sure you tell your doctor if you have any other medical problems, especially:

• Anorexia nervosa (an eating disorder) or

• Glaucoma, narrow angle or

• High blood pressure (or history of)—Sibutramine may make these conditions worse

• Brain disease or damage, or mental retardation or

• Seizures (history of)—Sibutramine may increase the chance of having seizures

• Gallstones (or history of)—Weight loss may make this condition worse

• Heart disease (or history of) or

• Stroke (or history of)—Increased blood pressure or heart rate caused by sibutramine may make these conditions worse

• Kidney disease (severe) or

• Liver disease (severe)—Higher blood levels of sibutramine may occur, increasing the chance of having unwanted effects

Take this medicine only as directed. Do not take more of it, do not take it more often, and do not take it for a longer time than directed by your doctor. To do so may increase the chance of developing unwanted effects, such as high blood pressure.

Follow a reduced-calorie diet while taking sibutramine, as directed by your doctor.

Sibutramine may be taken with or without food, on a full or empty stomach. However, if your doctor tells you to take it in a certain way, take it as directed.

You must follow a reduced-calorie diet while taking sibutramine in order to lose weight and keep the lost weight from returning.

Dosing—

The dose of sibutramine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of sibutramine. If your dose is different, do not change it unless your doctor tells you to do so.

The number of capsules that you take depends on the strength of the medicine.

• For oral dosage form (capsules):

  • For weight loss:

    • Adults—At first, 10 milligrams (mg) one time a day, usually in the morning. Your doctor may increase or decrease your dose if needed. However, the dose is usually not more than 15 mg a day.

    • Children—Use and dose must be determined by the doctor.

Missed dose—

If you miss a dose of sibutramine and you remember it within 2 to 3 hours, take it as soon as possible. If you do not remember the missed dose until later, skip the missed dose and return to your regular dosing schedule. Do not double doses.

Storage—

To store this medicine:

• Keep out of the reach of children.

• Store away from heat and direct light.

• Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.

• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

It is important that your doctor check your progress at regular visits. Sibutramine may increase blood pressure or heart rate and your doctor will check for these effects. Your doctor may need to adjust your dose.

If sibutramine does not seem to be working well, do not increase your dosage. Check with your doctor.

Do not take sibutramine while you are taking or within 2 weeks of taking medicines with monoamine oxidase (MAO) inhibitor activity , such as isocarboxazid (e.g., Marplan), phenelzine (e.g., Nardil), procarbazine (e.g., Matulane), selegiline (e.g., Eldepryl), or tranylcypromine (e.g., Parnate). Do not take an MAO inhibitor within 2 weeks of taking sibutramine. To do so may cause severe seizures, extremely high blood pressure, or a life-threatening adverse effect called the serotonin syndrome.

Do not drink excess alcohol while taking sibutramine.

Notify your doctor as soon as possible if you develop a skin rash, hives, or other allergic symptoms.

Sibutramine may cause dizziness, drowsiness, or poor judgment. Be sure you know how you react to this medicine before you drive, operate machinery, or do other things that could be dangerous if you are not alert and able to think clearly.

Sibutramine may cause dryness of the mouth. For temporary relief, use sugarless candy or gum, melt bits of ice in your mouth, or use a saliva substitute. However, if your mouth continues to feel dry for more than 2 weeks, check with your medical doctor or dentist. Continuing dryness of the mouth may increase the chance of dental disease, including tooth decay, gum disease, and fungus infections.

Side Effects of This Medicine

Along with its needed effects, a medicine may cause some unwanted effects. Some of these effects, such as high blood pressure, may not have signs or symptoms that you can see or feel. While you are taking sibutramine, your doctor will check your blood pressure and heart rate at regular visits.

Although not all of these side effects may occur, if they do occur they may need medical attention.

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

• Less common

  • Achiness;  chills;  fast or irregular heartbeat;  increased blood pressure ;  mental depression;  painful menstruation;  swelling of body or of feet and ankles  

  
   

• Rare

  • Bruising or red spots or patches on skin;  convulsions (seizures);  excessive bleeding following injury;  headache (severe);  rapidly changing moods;  skin rash;  weight gain (unusual) 

  
   

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

• More common

  • Anxiety;  constipation;  dizziness;  dryness of mouth;  headache;  irritability or unusual impatience ;  nervousness;  stuffy or runny nose;  trouble in sleeping 

  
   

• Less common

  • Abdominal pain;  back pain;  burning, itching, prickling, or tingling of skin;  change in sense of taste;  diarrhea;  drowsiness;  increase in appetite;  increased sweating;  increased thirst ;  indigestion;  nausea;  unusual warmth or flushing of skin 

  
   

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

In the U.S.—

• Appetite suppressant