Antispasmodic agent, atropine

Atropine has a mild antispasmodic action on the gallbladder and bile ducts. It has been superseded in gastroenterology by agents with fewer adverse effects. 

Mechanism of Action An anticholinergic agent that exerts an atropine-like action and produces an antispasmodic effect on smooth muscle, is a potent mydriatic, and inhibits salivation. Therapeutic Effect Relieves symptoms of Parkinson s disease and drug-induced extrapyramidal symptoms. 

Tertiary amines used for their antispasmodic properties are dicyclomine hydrochloride (Ben-tyl, others), oxyphencyclimine hydrochloride (daricon), flavoxate hydrochloride (Uripas), and oxyburynin chloride (Ditropan). The latter two are indicated specifically for urological disorders. These agents appear to exert some nonspecific direct relaxant effect on smooth muscle. In therapeutic doses they decrease spasm of the gastrointestinal tract, biliary tract, ureter, and uterus characteristic atropine-like effects on the salivary glands and the eye also are seen with oxybutynin. 

As a class, anticholinergics include the antihistamines, atropine and homatropine anti-Parkinsonian agents like benzotropine, procyclidine, and trihexyphenidyl the antimuscarinics of which atropine is the prototype and antispasmodics like dicyclomine and oxybutymin. Most antimuscarinics are amino-alcohols or their derivatives (usually esters or ethers), aminoamides, or other amines. Antimuscarinics can be divided into two groups. These are the naturally occurring alkaloids and their semisynthetic derivatives like atropine, homatropine, scopolamine, and hyoscyamine and the synthetic amine compounds such as anisotropine, dicyclomine, and ipratropium. 

Atropine (1) [a racemic mixture of (-i-)-and (-)-hyoscyamine (2)] and scopolamine [(-)-hyoscine] (3) are tropane-type alkaloids found in certain plants in the Solanaceae (nightshade) family nsed medicinally for centuries in Europe, such as Atropa belladonna, Hyos-cyamus niger, and Datura stramonium [7]. The antispasmodic activities of atropine are due to competitive antagonism of acetylcholine at the muscarinic receptor site. Scopolamine is also an anticholinergic agent, and most commonly used for the prevention of nausea and motion... 

Finally, one of the newer preparations which many people take with them on trips out of the country is a mixture of (1) a neuromuscular blocking agent (diphenoxylate hydrochloride) and (2) atropine, an antispasmodic drug. 

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