3. • Origin:
– Atropa belladona
– Datura stramonium
• Ester of tropic acid and tropine
• MoA
– Block muscarinic effects of Ach (competitive
antagonist)
– Do not interfere with release of Ach at cholinergic
nerve endings
– Does not distinguish between the M 1 , M 2 , and M 3
DR GEETANJALI VERMA
5. PHARMACOKINETICS
• Absorbed from the gut, parenteral sites and
mucous membranes
• Distribution: widely distributed in the body
• Metabolism: in liver (conjugation)
• 60% excretes unchanged in urine
• Effects disappear quickly within 2 Hrs except eye
• Crosses placental barrier & secreted in milk &
saliva
DR GEETANJALI VERMA
6. PHARMACODYNAMICS
SECRETIONS
• Salivary: dry mouth, difficult swallowing
• Gastric: reduces vol & total acidity
– Psychic, gastric & intestinal phases of gastric secretion
blocked partially
– Reduced secretion of mucin & gastric enzymes
• Others:
– Reduces secr in nose, mouth, pharynx, bronchi (viscid)
– Decr sweat
– No lacrimal inhibition
– Little effect on pancreatic & intestinal juices & bile
DR GEETANJALI VERMA
7. SMOOTH MUSCLE
• GI
– Reduces tone & motility (antispasmodic)
– Doesn’t interfere significantly with normal peristalsis
• Biliary tract : weak anti spasmodic
• Urinary tract: reduce tone of fundus of bladder &
enhance tone of trigonal sphincter -- uri retention
• Bronchi: relaxes musc of bronchi & bronchioles
• Uterus : -
• Eye: mydriasis (sphincter of iris & ciliary musc) –
paralysis of accomodation or cyclopegia
DR GEETANJALI VERMA
8. CVS
• Initially decreases HR – partial agonist of Ach
or stimulation of vagal nuclei
• Foll by tachy (↑ by 30-40 bpm) – blocking of
M2 ® in SA node
• Toxic doses: dilatation of cutaneous blood
vessels – atropine flush & hypotension
(depression of vasomotor center or periph
vasomotor paralysis)
DR GEETANJALI VERMA
9. CNS
• Mild stimulation of medullary vagal nuclei &
higher cerebral centres – ↓HR,↑ rate & depth
of resp
• Toxic doses: marked excitation
• Mod doses: controls tremors & rigidity in
parkinsonism
DR GEETANJALI VERMA
12. ADVERSE EFFECTS
• Due to extension of its pharma actions
– Dryness of mouth, difficult swallowing
– tachycardia
– Fever
– Constipation
– Blurring of vision, ppts glaucoma (elderly)
– Retention of urine (elderly)
– Local allergy: dermatitis, conjunctivitis, swelling of
eyelids
– Drugs causing synd of acute atropine intox: TCAs,
phenothiazines, anti histaminics
DR GEETANJALI VERMA
13. ACUTE BELLADONA POISONING
• Lethal dose: children 10-30mg, adults: 80-130mg
• Periph muscarinic blockade
– Dryness of mouth, difficult swallowing, thirst
– Tachy, palpitations
– Hyperpyrexia (inhibitino of sweating)
– Dil of pupils, blurred vision, photophobia
– Uri urgency, difficult micturition, retention
– Rash –face, neck , upper trunk
• Central actions
– Excitement, restlessness
– Motor incoord
– Slurring of speech, memory disturbance
– Confusion, hallucination, mania, delirium
– n/v, HTN
– Coma, paralysis of resp centre
DR GEETANJALI VERMA
14. • Diagnosis
Adding drop of pt’s urine in cat’s eye
pupillary dilatation
• t/t:
– Ingestion: gastic lavage
– Physostigmine 1-4mg (children 0.5-1mg) IV (pref
in CNS symp)
– Neostigmine 2-5mg sc
– Repeated at intervals of 1-2hrs
– Other symptomatic mgmt (dark room, tepid
sponging, oxygen, artificial vent, catheterisation)
DR GEETANJALI VERMA
