Atropin

Question 1

Receptors of parasympathetic System

Answer 1

1) Muscarnic receptors (MR) - > More common
2) Nicotinic receptors (NR

Question 2

Classification, succording to selectivit

Answer 2

1-Non-selective Muscarinic Antagonists: they block all types of muscarinic receptors.
2-Selective Muscarinic Antagonists

Question 3

Source and chemistry

Answer 3

natural from plant origin (Atropa belladonna).

Question 4

Absorption

Answer 4

1. Oral
   2.i.M
   3.i.V
2. Local eye drops

Question 5

Distribution

Answer 5

pass B.B.B.

Question 6

Metabolism

Answer 6

partly metabolized by the liver

Question 7

Excretion

Answer 7

partly excreted in urine unchanged.

Question 8

Why rabbits don’t effect by atropine

Answer 8

atropinase

Question 9

M.o. action:

Answer 9

non-selective competitive muscarinic antagonist.

Question 10

Local actions:

Answer 10

A- On skin: local anesthetic action

On eye:
1- Passive mydriasis
2- Loss of light reflex.
3- Cycloplegia
4- Increase IOP.
5- Xerophthalmia-> decrease lacrimal secretion

Question 11

Systemic Actions heart

Answer 11

Tachycardia
Atropine may cause initial transient bradycardia followed by tachycardia if given by IV

Question 12

Give reason for the intial bradycardia

Answer 12

1. Central action: atropine stimulates vagal cardio-inhibitory center (CIC)
2. Block of presynaptic M2 receptors (before blocking post-synaptic M2 receptors) leading
   to stimulation of acetylcholine release which acts on post-synaptic M2 receptors causing
   initial bradycardia.

Question 13

When tachycardia happens

Answer 13

Tachycardia occurs when atropine blocks post-synaptic M2 receptors

Question 14

Systematic action on blood vessels

Answer 14

1.Therapeutic doses of atropine have no effect on most blood vessels.
2.Large and toxic doses of atropine cause vasodilatation ( Atropine flush), especially in
children affecting face and neck. This may be due to histamine release.

Question 15

Bronchi

Answer 15

bronchodilatation.

Question 16

GIT

Answer 16

Inhibition in stomach secrétions

Question 17

Urinary bladder

Answer 17

relaxation of the wall and contraction of the sphincter

Question 18

Effect on gland بينشفها علي الكل 5

Answer 18

A)Lacrimal glands: decreases lacrimation causing dryness of the eye (Xerophthalmia).
B) Salivary glands: decreases salivary secretion leading to dry mouth (Xerostomia)
C)Bronchial glands: atropine decreases watery secretion leading to thick viscid secretion
D) Gastric glands: atropine decreases gastric secretion (both volume of secretion and HCl
F)Sweat glands: atropine decreases sweat secretion causing atropine fever

Question 19

CNS Actions (Stimulant actions:)

Answer 19

1-Stimulation of Respiratory center (R.C).
2- Stimulation of cardio-inhibitory center (C.I.C.)
3- Large doses stimulate the cerebral cortex leading to restlessness, anxiety,

Question 20

CNS Actions: Depressant actions

Answer 20

1-Antiemetic action: by blocking M receptors in the vomiting center.
2- Antiparkinsonian action: by blocking M receptors in the basal ganglia

Question 21

Therapeutic uses:
1- CNS:

Answer 21

Treatment of parkinsonism
II. Anti-emetic.
III. Pre-anaesthetic medication to:
Prevent bradycardia
Decrease in salivary and bronchial secretion to avoid pneumonia.
Avoid vomiting that may cause aspiration pneumonia

Question 22

Therapeutic uses: CVS

Answer 22

treatment of bradycardia and heart block.

Question 23

Respiratory system:

Answer 23

prevention bronchial asthma

Question 24

GIT:

Answer 24

Antispasmodic, antidiarrheal and treatment of peptic ulcer

Question 25

Urinary System

Answer 25

urinary incontinence

Question 26

Exocrine Glands:

Answer 26

Hyperhidrosis

Question 27

Adverse effects

Answer 27

1- Tachycardia,
2-Xerostomia.
3-increased IOP
4-contract the urinary sphincter
5-increases skin temperature due to decrease sweat secretions
6-decrease muco-ciliary effect

Question 28

Contraindications

Answer 28

1-Angina pectoris.
2-Constipation.
3-Glaucoma.
4- fever

Question 29

Synthetic Atropine Substitutes

Answer 29

1-Homatropine : Shorter duration of action.
And Less cycloplegia
2-Hyoscine butyl bromide (Buscopan): Treatment of intestinal colic and peptic ulcer
3-Benztropine: improves tremors.
4-Oxybutynin: treatment of urinary incontinence
5-Ipratropium- Tiotropium- Oxytropium: used for bronchial asthma

Question 30

Advantage of atropine 5

Answer 30

1-They are given by inhalation.
2-They do not cause dryness of bronchial secretion.
3- They do not decrease muco-ciliary activity.
4-don’t effect CNS