This document discusses anticholinergic drugs, with a focus on atropine as the prototype drug. It describes how anticholinergic drugs act by blocking muscarinic acetylcholine receptors in the autonomic nervous system and central nervous system. Specifically, it summarizes atropine's pharmacological actions, including stimulating the CNS and heart rate, causing dilation of the pupils, relaxing smooth muscles, decreasing secretions from glands, and slightly raising body temperature. It also lists some common anticholinergic drugs and their uses, such as treating peptic ulcers, intestinal spasms, asthma, and as a pre-anesthetic medication.

1. ANTICHOLINERGIC DRUGS
Mangesh Bansod
Asst. Prof.,
SDDVCPRC, Panvel

2. ANTICHOLINERGIC DRUGS
(Muscarinic receptor antagonists,
Atropinic, Parasympatholytic)
 The term ‘anticholinergic drugs’ is restricted to those which block
actions of Ach on autonomic effectors and in the CNS exerted
through muscarinic receptors.
 Nicotinic receptor antagonists also block certain actions of
ACh, they are generally referred to as ‘ganglion
blockers’ and ‘neuromuscular blockers’.
 Atropine, the prototype drug of this class, is highly selective for
muscarinic receptors

4. PHARMACOLOGICAL ACTIONS(Atropine as prototype)
 1. CNS - Atropine has an overall CNS stimulant action.
• Atropine stimulates many medullary centres —vagal, respiratory, vasomotor.
• It depresses vestibular excitation and has antimotion sickness property.
probably there is a cholinergic link in the vestibular pathway, or it may be
exerted at the cortical level.
• By blocking the relative cholinergic overactivity in basal ganglia, it suppresses
tremor and rigidity of parkinsonism.
• High doses cause cortical excitation, restlessness, disorientation,
hallucinations and delirium followed by respiratory depression and coma.

5.  2. CVS – Heart- The most prominent effect of
atropine is tachycardia. It is due to blockade of
M2 receptors on the SA node through which
vagal tone decreases HR.
 3. Eye - Topical instillation of atropine causes
mydriasis, abolition of light reflex
and cycloplegia lasting 7–10 days.This results
in photophobia and blurring of near vision
PHARMACOLOGICAL ACTIONS(Atropine as prototype)

6.  4. Smooth muscles - All visceral smooth muscles that receive
parasympathetic motor innervation are relaxed by atropine (M3
blockade).
 Tone and amplitude of contractions of stomach and intestine are
reduced; the passage of chyme is slowed—constipation may occur,
spasm may be relieved.
 Atropine causes bronchodilatation and reduces airway resistance,
especially in COPD and asthma patients.
 Atropine has relaxant action on ureter and urinary bladder; urinary
retention can occur in older males with prostatic hypertrophy.
PHARMACOLOGICAL ACTIONS(Atropine as prototype)

7.  5. Glands - Atropine markedly decreases sweat, salivary,
tracheobronchial and lacrimal secretion (M3 blockade). Skin and eyes
become dry, talking and swallowing may be difficult.
 Atropine decreases secretion of acid, pepsin and mucus in the
stomach
 6. Body temperature - Rise in body temperature occurs at higher
doses. It is due to both inhibition of sweating as well as stimulation of
temperature regulating centre in the hypothalamus.
 7. Local anaesthetic - Atropine has a mild anaesthetic action on the
cornea.
PHARMACOLOGICAL ACTIONS(Atropine as prototype)

8.  Ipratropium bromide - ipratropium is effective in COPD
 Propantheline -it was a popular anticholinergic drug used for peptic ulcer and
gastritis.
 Oxyphenonium -similar to propantheline, recommended for
peptic ulcer and gastrointestinal hypermotility
 Clidinium -antisecretoryantispasmodic has been used in combination with
benzodiazepines for nervous dyspepsia, gastritis, irritable bowel syndrome, colic,
peptic ulcer, etc.
 Isopropamide -indicated in hyperacidity, nervous dyspepsia, irritable bowel
and other gastrointestinal problems
 Dicyclomine - It exerts antispasmodic action , Dysmenorrhoea and irritable bowel are
other indications
ATROPINE SUBSTITUTES

9.  Oxybutynin - This newer antimuscarinic has high affinity for receptors
in urinary bladder and salivary glands alongwith additional smooth
muscle relaxant and local anaesthetic properties.
 Because of vasicoselective action, it is used for detrusor
instability resulting in urinary frequency and urge incontinence.
 Beneficial effects have been demonstrated in post-prostatectomy
vasical spasm, neurogenic bladder, spina bifida and nocturnal
enuresis.
Vasicoselective drugs

10. Mydriatics
 Atropine is a potent mydriatic but its slow and
long-lasting action is undesirable for refraction testing.
 Tropicamide- It has the quickest (20–40 min) and briefest (3–6
hours) action, but is a relatively unreliable cycloplegic.

11. USES
 I. As antisecretory
1. Preanaesthetic medication - When irritant general anaesthetics (ether) were used, prior
administration of anticholinergics (atropine,
hyoscine, glycopyrrolate) was imperative to check increased salivary and
tracheobronchial secretions.
 2. Peptic ulce
 II. As antispasmodic –
1. Intestinal and renal colic, abdominal cramps:
symptomatic relief
2. Nervous, functional and drug induced diarrhoea
3. Spastic constipation, irritable bowel syndrome:
4.To relieve urinary frequency and urgency, enuresis in children
III. Bronchial asthma, asthmatic- bronchitis, COPD
IV. As mydriatic and cycloplegic

12. USES
 V. For central action
 1. Parkinsonism
 2. Motion sickness
 VI.To antagonise muscarinic effects of drugs and poisons

13. Thank you…….