Sibutramine is a medication that assists with weight-loss by altering neurotransmitters within the brain. Neurotransmitters are chemicals that are produced and released by nerves in order to communicate with other nerves. Released neurotransmitters may attach to other nerves or they may be taken up again by the nerves that release them a process termed reuptake. Sibutramine blocks the reuptake of the neurotransmitters dopamine norepinephrine and serotonin. Blocking the reuptake of neurotransmitters alters the balance of neurotransmitters within the nerve cells and thereby affect nerve function and interaction.

Patients taking sibutramine may achieve a 5-10 reduction from their baseline weight. Additionally sibutramine-assisted weight loss has been accompanied by improvement in blood lipids e.g cholesterol. Sibutramine was approved by the FDA in 1997.

Sibutramine is taken once daily generally in the morning. Therapy usually is started with one 10mg tablet per day. The dose may be increased to 15mg by the physician after several weeks to achieve the desired effect. Doses of up to 60mg have been studied. Sibutramine may be taken with or without food.

In general sibutramine is well-tolerated. The most common side effects have been constipation inability to sleep headache and dry mouth. Other side effects include abdominal pain acne rash chest pain anxiety joint pain back pain excitation depression sweating dizziness drowsiness changes in taste irregular or painful menstrual periods flu-like syndrome increased cough muscle pain nausea vomiting neck pain nervousness palpitations tingling of the extremities sore throat and sinus congestion.

Abnormal liver tests have been reported in 1 in 60 persons who receive sibutramine.

Sibutramine must be converted in the liver to its active form. This conversion is inhibited by ketoconazole Nizoral cimetidine Tagamet and erythromycin Erytab Eryc Ilosone and use of these drugs can result in decreased conversion and effectiveness of sibutramine. Several other drugs may have a similar effect. These other drugs include clarithromycin Biaxin danazol Danocrine diltiazem Cardizem Tiazac Dilacor fluconazole Diflucan fluoxetine Prozac itraconazole Sporanox propoxyphene Darvon troleandomycin Tao and verapamil Verelan Covera Calan Isoptin.

In patients receiving one of the drugs from a class of drugs known as selective serotonin reuptake inhibitors SSRIs--e.g. fluoxetine Prozac fluvoxamine Luvox paroxetine Paxil sertraline Zoloft--at the same time as monoamine oxidase inhibitor drugs MAO inhibitors there have been reports of serious reactions serotonin syndrome. The serotonin syndrome may include one or more of the following: agitation anxiety dizziness confusion excessive sweating disorientation painful joints vomiting hyperexcitement fever loss of coordination loss of consciousness shivering fast heart rate tremor and weakness. As discussed previously sibutramine like the SSRIs blocks the reuptake of serotonin and may also cause the serotonin syndrome. Therefore sibutramine should not be used with MAO inhibitors and there should be at least a 2-week interval between stopping an MAO inhibitor and starting sibutramine. Similarly there should be at least a 2-week interval after stopping sibutramine and starting an MAO inhibitor. Serotonin syndrome also has been reported with the use of SSRIs at the same time as medications used for migraines such as sumatriptan Imitrex zolmitriptan Zomig and dihydroergotamine DHE as well as dextromethorphan found in many cough medications such as Robitussin-DM meperidine Demerol pentazocine Talwin and fentanyl Duragesic or lithium Eskalith. Therefore these drugs should not be used with sibutramine.

Sibutramine is used for weight loss in conjunction with a low calorie diet. Specific populations for whom the medication is recommended are those with an initial body mass index of more than 30 kg/m2 27 mg/m2 if they also have other risk factors such as diabetes mellitus high cholesterol or hypertension.

Capsules should be stored at 25°C 77°F. Brief periods at higher or lower temperatures i.e. 15-30°C 59-86°F are permitted. The medication should be stored in a tight light-resistant container. The capsules should be protected from heat and moisture.