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Anticholinergic agent

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Anticholinergic agent

  1. 1. Cholinergic Antagonist Presented by - Ashok Gautam Skb college of pharmacy
  2. 2. Cholinergic antagonist • These drugs block the response of Ach in the muscarine receptor by competitively binding to it and inhibiting any response. • They have opposite pharmacological response of Ach
  3. 3. SAR • The R1 or R2 groups must be carbocyclic or heterocyclic • The R3 group can be hydrogen, hydroxyl (-OH), hydroxymethyl (-CH2OH), amide • The X is mostly Ester in most potent derivatives but it can be a ether oxygen or absent completely • The N substituent cab be both quaternary ammonium salt or tertiary amine with different alkyl groups • The distance between the ring substituted carbon and nitrogen is not fixed but maximum potency requires about 2 carbon units • (Note: The SAR does not say anything about selectivity for muscarinic subtypes) C X (CH2) N substituent R1 R3 R2 General framework of Anticholinergics
  4. 4. • Medical use In Sooth muscle spasm In cold n flu (to reduce nasal secretion) Previously in ulcer (but now replaced by H2 antagonist and proton inhibitors) Overactive bladder (to much urination) Motion sickness Treat organophosphate poisoning Parkinson (brain disease where nerves start degrading and person slowly goes crazy)
  5. 5. SAR of Cholinergic Agent v/s and Anticholinergic Agent A) Nitrogen group • In agonist the N can only be quanternary but • In antagonist N can be both quanternary or tertiary Methacholone Orphendrine
  6. 6. B) Ethylene group • In agonist the no of ethylene is fixed at only 2 but • In antagonist no of ethylene can range from 2-4 Bethaneco l carbamat e Glycopyrrolate
  7. 7. C) Selectivity • In agonist the methyl substitution in ethylene group controls selectivity of muscarinic or nicotinic but • In antagonist no such feature is present. Still It only antagonizes muscarinic only Methacholone Muscarinic selective
  8. 8. Classification A)Solanaceous alkaloid and analogs • Atropine • Hyoscyamine • Scoplamine • Homatropine • Ipratropium and Tiotropium B) Synthetic Cholinergic blocking agent 1) Aminoalcohol Esters • Clinidium bromide • Cyclopentolate • Dicyclamine • Glycopyrrolate • Mepenzolate • Methantheline • Oxyphencyclimine • Propantheline • Oxybutynin • Solifenacin
  9. 9. 2) Aminoalcohol Ethers • Benztropine • Orphenadrin 3) Aminoalcohol • Biperiden • Procyclidine • Trihexethyl chloride • Tolterodine 3) Aminamides • Isopropamide • Tropicamide • Darifenacin 4) Miscellaneous • Diphemanil • Ethopropazine • Papaverine
  10. 10. Atropine Atropine • Anticholinergic, blocks muscarinic receptors • Alkaloid extracted from Solanaceae plant • first anticholinergic. • It is an Ester of tropine and tropic acid and used as a sulphate Salt in racemic from • At therapeutic does it can penetrate the brain and stimulate the CNS • Uses • Treat Bardycardia • Reduce secretion before surgery • Treat Iritis (painful inflammation of eye) • Organophosphate poisoning (only to decrease muscarinic action, not an antidote like PAM) • MOA – It competitively binds to muscarinic receptor and antagonizes it thus blocking all cholinergic effects
  11. 11. Hyoscyamine Hyoscyamine • It is the levorotary isomer of atropine USE: • various gastrointestinal disorders including spasms, peptic ulcers, irritable bowel syndrome, pancreatitis, and cystitis. • Used to relieve some heart problems, • control some of the symptoms of Parkinson's disease, • control of respiratory symptoms
  12. 12. Scopolamine Scopolamine • In the form of a levorotatory • Action on the higher nerve centers • Transdermal patch of scopolamine is available side effects: • include sleepiness, blurred vision, dilated pupils, and dry mouth Use: Postoperative nausea and vomiting and sea sickness, Motion sickness (where it is often applied as a transdermal patch behind the ear), Gastrointestinal spasms, Renal or biliary spasms, Aid in radiology and endoscopy, Irritable bowel syndrome, Clozapine-induced hypersalivation, Eye inflammation
  13. 13. Ipratropium bromide Ipratropium • It is a Quaternary ammonium derivative of atropine • used in inhalation therapy to produce dilation of bronchial smooth muscle for acute asthmatic attacks. • The drug produces bronchodilation by competitive inhibition of cholinergic receptors bound to smooth muscle of the bronchioles
  14. 14. Tiotropium bromide Tiotropium bromide • Used in an inhalation device to deliver the drug into the lungs. • It is indicated in the treatment of chronic obstructive pulmonary disease (COPD), including chronic bronchitis and emphysema • Long-acting, 24-hour
  15. 15. 1) Aminoalcohol Esters Clinidium bromide Clinidium bromide • Marketed alone and in combination with the minor tranquilizer chlordiazepoxide (Librium) in a product known as Librax. • For the treatment of GI complaints is the use of an anxiety-reducing agent together with an anticholinergic agent
  16. 16. Cyclopentolate Cyclopentolate • It is used only for its effects on the eye, • Acts as a parasympatholytic. • When placed in the eye, it quickly produces cycloplegia and mydriasis. • Usefulness in refraction studies. • Can be used, as a mydriatic in the management of iritis, iridocyclitis, keratitis
  17. 17. Dicyclamine Dicyclamine • Used for its spasmolytic effect on various smooth muscle spasms, particularly those associated with the GI tract. • It is also useful in dysmenorrhea, pylorospasm, and biliary dysfunction.
  18. 18. Glycopyrrolate Mepenzolate Methantheline Oxyphencyclimine
  19. 19. 2) Aminoalcohol Ethers Benztropine • Has anticholinergic, antihistaminic, and local anesthetic properties. • Its anticholinergic effect makes it applicable as an antiparkinson agent. • It is about as potent anticholinergic as atropine
  20. 20. Orphenadrin Orphenadrin • Closely related to diphenhydramine structurally but has much lower antihistaminic activity and much higher anticholinergic action • It does reduce voluntary muscle spasm, however, by a central inhibitory action on cerebral motor areas.
  21. 21. 3) Aminoalcohol Biperiden Biperiden • Has a relatively weak visceral anticholinergic, but a strong nicotinolytic action in terms of its ability to block nicotine induced convulsions • Has a relatively strong musculotropic action, which is about equal to that of papaverine, in comparison with most synthetic anticholinergic drugs
  22. 22. Procyclidine Procyclidine • Effective peripheral anticholinergic • Ability to relieve voluntary muscle spasticity by its central action • Treatment of Parkinson syndrome • Reduce muscle rigidity in postencephalitic, arteriosclerotic, and idiopathic types of the disease
  23. 23. 4) Aminoamides Isopropamide Isopropamide • Potent anticholinergic, • Producing atropine-like effects peripherally • Long duration of action. • A single dose can provide antispasmodic and antisecretory effects for as long as 12 hours. USE:- • It is used as adjunctive therapy in the treatment of peptic ulcer and other conditions of the GI tract associated with hypermotility and hyperacidity.
  24. 24. Tropicamide Tropicamide • Effective anticholinergic for ophthalmic use • Produces short acting mydriasis and cycloplegia • To achieve mydriasis, either 0.5% or 1.0% concentration may be used • Treatment of acute iritis, iridocyclitis, and keratitis
  25. 25. 5) Miscellaneous Diphemanil Ethopropazine Papaverine

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