Dicyclomine (Bentyl)
Bentyl® | Barmine™
Classification:
Autonomic Agents
Gastrointestinal Agents
Description: Dicyclomine is an antimuscarinic, anticholinergic drug. It is used as an antispasmodic agent in the treatment of diarrhea-predominant irritable bowel syndrome. Although dicyclomine is a tertiary amine, it does not produce characteristic atropine-like effects on the salivary or sweat glands, or on the cardiovascular system. Dicyclomine is an old drug, but it remains one of the more frequently prescribed agents among the many antimuscarinics currently marketed. There is a black box warning against the use of this drug in infants < 6 months of age, due to reports of severe adverse effects of dicyclomine in very young infants (See Contraindications) when the drug was used to treat symptoms of colic. Dicyclomine was approved by the FDA in 1950.
Mechanism of Action: Dicyclomine is an antimuscarinic, anticholinergic agent. The underlying mechanism of activity is unknown, but it is believed to exert a nonspecific, local, direct spasmolytic (musculotropic) action on the smooth muscle of the GI tract, thereby decreasing muscular tone and motility. Dicyclomine also can relieve GI smooth muscle spasm via effects exerted at the acetylcholine muscarinic receptor. Dicyclomine has 1/8 the milligram potency of atropine.
Antimuscarinic agents usually will readily inhibit the increases in GI tract tone and motility resulting from emotional trauma, insulin-induced hypoglycemia, or the administration of parasympathomimetic agents. Other causes of increased GI tone and motility, including those secondary to histamine or vasopressin, may not respond to antimuscarinic agents.
Bentyl Capsules(Cap 10 mg)
Pharmacokinetics: Dicyclomine is absorbed rapidly from the GI tract and reaches peak plasma concentrations within 1 - 1.5 hours following oral administration. Intramuscular dicyclomine is nearly twice as bioavailable as oral dicyclomine. The volume of distribution is 3.65 L/kg. The specific mechanisms of elimination have not been determined. Approximately 80% of an oral dose is excreted in the urine and about 9% in the feces. The elimination half-life is roughly 9 - 10 hours.
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[ Revised 4/6/2006 1:48:00 PM ]
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