Levsin (Hyoscyamine Sulfate) - Description and Clinical Pharmacology

Rx Only

DESCRIPTION

Levsin® injection (hyoscyamine sulfate injection USP) is a sterile solution containing 0.5 mg hyoscyamine sulfate per mL in water for injection.

Levsin® is one of the principal anticholinergic/antispasmodic components of belladonna alkaloids. The empirical formula is (C₁₇H₂₃NO₃)₂•H₂SO₄•2H₂O and the molecular weight is 712.85. Chemically, it is benzeneacetic acid, alpha-(hydroxymethyl)-,8-methyl-8-azabicyclo [3.2.1.] oct-3-yl ester, [3(S)-endo]-, sulfate (2:1), dihydrate with the following structure:

The 1 mL ampuls contain as inactive ingredients: water for injection, pH is adjusted with hydrochloric acid when necessary.

CLINICAL PHARMACOLOGY

Levsin® 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. It is completely devoid of any action in the autonomic ganglia. Levsin® inhibits gastrointestinal propulsive motility and decreases gastric acid secretion. Levsin® also controls excessive pharyngeal, tracheal and bronchial secretions.

Levsin® disappears rapidly from the blood and is distributed throughout the entire body. The half-life of Levsin® is 3½ hours. Levsin® 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® passes the blood brain barrier and the placental barrier.