Adult: Patients w/ BMI ≥30 kg/m2 or ≥27 kg/m2 in the presence of other risk factors: Initially, 10 mg once daily, may increase to 15 mg once daily after 4 wk; 5 mg dose may be given to patients who cannot tolerate the 10 mg dose. Max: 15 mg daily. Elderly: >65 yr Contraindicated.
Renal Impairment
Severe: Contraindicated.
Hepatic Impairment
Severe: Contraindicated.
Administration
May be taken with or without food.
Contraindications
Major eating disorder (anorexia nervosa or bulimia nervosa), inadequately controlled HTN (>145/90 mmHg). History of coronary artery disease, CHF, arrhythmias, stroke. Patients >65 yr of age. Severe renal or hepatic impairment. Lactation. Concomitant use w/ MAOIs and other centrally acting wt loss drugs.
Special Precautions
Patient w/ narrow angle glaucoma, seizure disorder and those at risk of bleeding events. Mild to moderate renal or hepatic impairment. Pregnancy.
Symptoms: Tachycardia, HTN, headache, dizziness. Management: Symptomatic and supportive treatment. Establish a patent airway. β-blockers may be considered to control HTN or tachycardia, but caution is advised.
Drug Interactions
Increased plasma concentration w/ CYP3A4 inhibitors (e.g. ketoconazole, erythromycin). Potentially Fatal: Risk of serotonin syndrome w/ MAOIs (e.g. phenelzine, selegiline). Increased risk of cardiac valve dysfunction w/ other centrally-acting wt loss agents.
Action
Description: Mechanism of Action: Sibutramine inhibits the reuptake of norepinephrine and serotonin, and to a lesser extent, dopamine. Pharmacokinetics: Absorption: Rapidly absorbed from the GI tract. Time to peak plasma concentration: W/in 3-4 hr. Distribution: Rapidly and extensively distributed into body tissues. Plasma protein binding: 97%. Metabolism: Undergoes hepatic metabolism principally by CYP3A4 isoenzyme to desmethyl metabolites, M1 and M2, further metabolised via hydroxylation and conjugation to inactive metabolites. Excretion: Mainly via urine (77%, as inactive metabolites). Elimination half-life: 14 hr (M1); 16 hr (M2).