Accepted Uses of Anticholinergic Drugs

-peptic ulcer (adjunct agent)

-irritable bowel syndrome: suggests excess parasympathetic bowel activity

-hypermotility of bladder (cystitis)

-urinary incontinence

-hypersecretory syndrome (inc. anesthetic induced)

-sialorrhea

-drug-induced or other causes of bradycardia : emergency use of atropine

-anticholinesterase toxicity

-muscarine toxicity

-motion sickness

-biliary tract spasm: smooth muscle of biliary tract, mimics acute appendicitis

-enuresis: bed-wetting

-chronic rhinitis

-diarrhea

-Parkinson’s disease (adjunct)

*”adjunct” means that this wouldn’t be the primary drug class to treat this disorder

Appropriate chemical classification of these agents; depending on whether these structures are tertiary amines or quaternary ammonium derivatives, the ability to penetrate the CNS varies. For example, Ipratropium to treat asthmatics shouldn’t be able to get into the brain or produce all the bizarre side effects. So as a result, the quaternary ammonium structure does very well—doesn’t affect the CNS. This is a synthetic compound, not a Belladonna alkaloid. Tertiary amines such as atropine have tremendous CNS effects, even at therapeutic doses. At toxic levels, very significant bizarre CNS effects. Tertiary amines are not synthetic, and are belladonna alkaloids.

You’re not responsible for structures, however you are responsible for the names. Shown are some classical belladonna alkaloids, atropine and scopolamine. Right below it, there are some drugs that are never classified as anticholinergics or antimuscarinics, but they have significant anticholinergic side effects. So diphenhydramine (brand name: Benadryl) is an antihistamine, blocks the H1 receptor. Benadryl has a notorious anticholinergic side effect, close to 80-90% of pts will complain of dry mouth, dry eyes, sedation. Diphenhydramine is used in cold meds and in sleep aids.

Some drugs used in psychiatry are the so-called tricyclic antidepressants. They are never classified as anticholinergics, yet have profound anticholinergic side effects.

Category: Pharmacology Notes