Sibutramine can cause mydriasis, therefore use with caution in patients with narrow angle glaucoma. Sibutramine is not recommended for use during breast feeding since excretion into human breast milk has not been determined. Patients with mild to moderate hepatic impairment or renal insufficiency do not require dosage adjustment. Sibutramine is not recommended for use in patients with severe hepatic dysfunction or severe renal impairment. Safety and efficacy in patients under 16 years old have not been established.
Caution is recommended due to possible additive negative effects on blood pressure or heart rate.
Sibutramine inhibits the reuptake of norepinephrine, serotonin, and dopamine from synapses in brain tissue. Sibutramine does not act by release of these monoamines. Both sibutramine and its metabolites down-regulate cortical B2 receptors. By these mechanisms, sibutramine and its metabolites have been shown to reduce food intake. Peak plasma concentrations of the active metabolites are reached within 3-4 hours.