Each tablet also contains as inactive ingredients: FD&C blue #1, lactose monohydrate, magnesium stearate, mannitol, starch and stearic acid.

Levsin®/SL inhibits specifically the actions of acetylcholine on structures innervated by postganglionic cholinergic nerves and on smooth muscles that respond to acetylcholine but lack cholinergic innervation. These peripheral cholinergic receptors are present in the autonomic effector cells of the smooth muscle, cardiac muscle, the sinoatrial node, the atrioventricular node, and the exocrine glands. At therapeutic doses, it is completely devoid of any action on autonomic ganglia. Levsin®/SL inhibits gastrointestinal propulsive motility and decreases gastric acid secretion. Levsin®/SL also controls excessive pharyngeal, tracheal and bronchial secretions.

Levsin®/SL is absorbed totally and completely by sublingual administration as well as oral administration. Once absorbed, Levsin®/SL disappears rapidly from the blood and is distributed throughout the entire body. The half-life of Levsin®/SL is 2 to 3½ hours. Levsin®/SL is partly hydrolyzed to tropic acid and tropine but the majority of the drug is excreted in the urine unchanged within the first 12 hours. Only traces of this drug are found in breast milk. Levsin®/SL passes the blood brain barrier and the placental barrier. The tablets can be taken orally with the same pharmacological effects occurring; however, the effects may not occur as rapidly as with sublingual administration.