Transcript
PARASYMPATHOLYTICSBY
SYED FAYYAZUDDIN
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CONTENTSINTRODUCTION
CLASSIFICATION
PHARMACOLOGICAL ACTIONS
DRUGS
USES
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INRODUCTIONAcetylcholine.
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Receptor Location
M1 CNS, Postganglionic neurons.
M2 Myocardium, Smooth muscles.
M3 Exocrine glands, Smooth muscles.
M4 CNS
M5 CNS
M6 CNS
M7 CNS
M8 CNS
M9 CNS
M10 HEART
M11 BRONCHI
M12 BRONCHI
M13 CNS
NN Postganglionic neurons.
NM Skeletal muscles.
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MECHANISM OF ACTION
IP3 DAG cAMP Na+/K+
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Blocks action of Ach on autonomic effectors through
muscarinic receptors.
Competitive antagonists.
Prototype Atropine.
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Classification1. Natural alkaloids:
AtropineHyoscine
2. Semisynthetic derivatives:HomatropineHyoscine butyl bromideAtropine methonitrate.
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3. Synthetic compounds:
A.Mydriatics:
Tropicamide
B.Antisecretory-antispasmodic:
Dicyclomine.
Propanthaline.
Biperden.
C.Antiparkinsonian:
Tryhexyl phenidyl.
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GANGLIONIC BLOCKING AGENTS.
COMPETATIVE BLOCKERS
Hexamethonium
Mecamylamine
PERSISTANT DEPOLARISING BLOCKERS
Nicotine
Anticholinesterases04/10/2023 11
PHARMACOLOGICAL ACTIONSCNS
Stimulates many medullary centres. Vagal, respiratory and vasomotor. Anti-motion sickness property.
High dose cause Restlessness Disorientation Hallucinations Respiratory depression Coma.
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CVSprimarily in modifications of the heart rate:very low dose, it can give a slight cardiac slowingtherapeutic dose there is generally cardiac accelerationIt does not have vascular effects since there is no
parasympathetic tonus on the vessels but it inhibits vasodilatation caused by an intravenous injection of acetylcholine.
It does not induce modifications of arterial pressure in spite of increased cardiac rate.
in very high or toxic dose, it induces a fall of the arterial pressure by depression of the vasomotor centers
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PHARMACOLOGICAL ACTIONSEYS
MydriasisCycloplegiaPhotophobia.
SMOOTH MUSCLESRelaxationM3 BlokadeTone is reducedConstipationBronchodilation (asthma)
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PHARMACOLOGICAL ACTIONSGLANDS
SweatBronchial secretionsLacrinal secretions.Acid, pepsin and mucus in stomach.
BODY TEMPERATUREInhibition of sweatingTemperature regulatory centre in hypothalamusAtropine fever
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Sensitivity
Gastric glands and smooth muscle.
Smooth muscle intestine and bladder.
Eye, bronchial muscle and heart.
Saliva , sweat, bronchial secretions.
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TROPICAMIDEBlocks the response of sphincter muscle of iris and ciliary
muscles to cholinergic stimulation thus causing mydriasis.Stronger preparation also paralyzes accommodation.Acts within 15-30 m and duration is 3-8 h.typically used during eye examinations such as the dilated
fundus examination, but it may also be used before or after eye surgery.
ADVERSE REACTIONS: Blurred visionPhoto phobiaIncreased intraocular pressureDry mouthTachycardiaHeadacheAllergic reactionsNausea Vomiting
DICYCLOMINEIt is a smooth muscle relaxant. Irritable Bowel Syndrome (also known as spastic colon). It relieves muscle spasms and cramping in the gastrointestinal
tract by blocking the activity of acetylcholine on cholinergic (muscarinic) receptors on the surface of muscle cells.
ADVERSE REACTIONS:
Dry mouthTachycardiaHeadacheAllergic reactionsNausea Vomitingconfusion agitation
HEXAMETHONIUMGanglionic blockerN receptor antagonist, acts in autonomic ganglia.Does not have any effect on muscarinic Ach receptors.Acts at receptors at neuromuscular junction responsible for
skeletal muscle motor response.
ADVERSE EFFECTS : ConstipationUrinary retentionGlaucomaBlurry visionDecreased lacrymal secretionDry mouth (xerostomia)
USESAntisecretory
PreanaesthticThe main reasons for using anticholinergic drugs were
drying of secretions and protection against vagal over activity.
Blocks responses to vegal refluxes induced by sergical manipulations of visceral organs.
Peptic ulcerPulmonary embolism
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AntispasmodicSpactic constipationNervous and drug induced diarrhoea.
Asthama, COPD
Cardiac vagolytic Bradycardia
Central actionsParkinsonismMotion sickness
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ReferencesTripathi KD. Anticholinergic drugs.In Essentials of medical
Pharmacology. 5th ed. JP Brothers Medical publishers (P) Ltd: New Delhi; 2003. pp. 93-102.
Katzung, Bertram.G, Basic and clinical pharmacology.10th ed. Mc Graw Hill. USA(NY); 2006. pp. 482-9.
Goodman & Gilman’s, The Pharmacological Basis Of Therapeutics. 11th ed. Mc Graw Hill. USA(NY); 2006. pp. 121-9.
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