Anticholinergic drugs work by competitively blocking acetylcholine from binding to muscarinic receptors. This results in various effects including mydriasis, cycloplegia, increased intraocular pressure, bronchodilation, decreased gastrointestinal motility and secretions, urinary retention, and inhibition of certain central nervous system functions. Anticholinergic drugs have therapeutic uses such as facilitating eye exams, treating conditions like heart block, motion sickness, and Parkinson's disease, and preventing side effects from anesthesia. However, they can cause adverse effects like dry mouth, blurred vision, constipation, and tachycardia.

1. AnticholinergicAnticholinergic
drugsdrugs
Dr Heba A. Mahmoud

3. Anti-muscarinic drugsAnti-muscarinic drugs
Mode of action:
Competitive antagonist compete with acetyl
choline for muscarinic receptors

4. Actions ofActions of Anti-CholinergicsAnti-CholinergicsActions ofActions of Anti-CholinergicsAnti-Cholinergics
Eye: blocks all cholinergic activity on the eye, resulting in
 passive mydriasis
 cycloplegia (inability to focus for near vision).
 Increase intraocular pressure
CVS: ↑HR (after initial HR)↓
↑ AVN conduction
Large dose atropine flush
Respiratory system: bronchodilatation
↓ secretions

5. Actions of Anti-CholinergicsActions of Anti-Cholinergics
GIT: antispasmodic reduce gastrointestinal tract motility
↓ gastric secretion
dry mouth and constipation
Urinary system: Relax bladder and retention of urine
Secretions: decrease all secretions (except milk, bile)
CNS: excitatory , inhibition of Vomiting centre ,
antiparkinsonian.
Anti-motion sickness

6. Therapeutic uses of Anti-CholinergicsTherapeutic uses of Anti-Cholinergics
Fundus examination and iridocyclitis (Mydriatic )
Atropine
Tropicamide is used but short acting, 2 - 4 hrs
Antidote for cholinergic agonists e.g. Organophosphorus
poisoning (Atropine )
 Heart block, vasovagal attack (Atropine )
Intestinal, biliary and renal Colic (hyoscine butyl
bromide)
Motion sickness (hyoscine)
Peptic ulcer: pirenzepine

7. Therapeutic uses of Anti-CholinergicsTherapeutic uses of Anti-Cholinergics
(cont.)(cont.)
Nocturnal enuresis and urinary incontinence
(emebronium is better) .
Parkinsonism (benztropine)
Bronchial asthma ipratropium is used by inhalation
Preanesthetic medication to stimulate respiratory
center , prevents vomiting, prevent excess
bronchial and salivary secretions and protect heart
from excess vagal tone
(Hyoscine)

8. Anti-CholinergicsAnti-Cholinergics adverse effectsadverse effects
 Dry mouth
 Blurred vision, xero-ophthalmia (dry eye), glaucoma
 Tachycardia
 Constipation
 Retention of urine
 Hot and flushed skin
Anti-CholinergicsAnti-Cholinergics contraindicationcontraindication
 Glaucoma
 Tachycardia
 Paralytic ileus
 Senile hypertrophy of prostate
 Allergy to atropine