Antimuscarinics

Question 1

How do AM’s work?

Answer 1

Competitive antagonists of ACH at muscarinic. Post ganglionic target tissues innervation by PNS primarily and SNS to sweat glands.

Therefore primarily reduce activity of PNS

Question 2

What are the clinical uses of AM’s?

Answer 2

A: bronchodilator
C: bradycardia
D: mydriatic, anti-Parkinson’s, premed (sedation and amnesia)
G: anti sialagogue and anti spasmodic

Question 3

Give a vague overview of the three AM drugs we commonly use?

Answer 3

All metab9lised by liver esterases and excreted via the kidneys.

Hyoscine: tertiary amine (crosses), large amounts of sedation, anti-sialagogue and mydriasis, some anti emesis.

Atropine: tertiary, large amounts of tachy and less of everything else.

Glyco: quaternary, so medium amounts of tachy, bronchodilation and anti spit.

Question 4

What is anticholinergic syndrome?

Answer 4

Cross BBB to cause an acute central syndrome

Central: altered mental status, hallucinations, ataxia, coma.

Peripheral: dry mouth, mydriasis, blurred vision, ileus, urinary retention and hot dry vasodilator skin.