Histaminic Agent.pptx
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This document discusses various types of antihistamine agents. It describes 20 first generation antihistamines that work by blocking the H1 receptor to relieve allergic symptoms. It also discusses 5 second generation antihistamines that are less sedating. Additionally, it covers 3 H2 receptor antagonists that decrease stomach acid production and 4 proton pump inhibitors that irreversibly block the gastric acid pump. The document provides details on the mechanism of action and uses of each type of antihistamine and acid reducer.
Histaminic Agent.pptx
- 1. BY - KARTIK TIWARI
- 2. Antihistaminic Agents ● Histamine:- ● Histamine are nitrogen containing compound of amine. Histamine produced in the animal cell which produce local immune response. ● They regulate physiological functions and act as neurotransmitter ● Synthesis:- ● Histamine is synthesized in Golgi apparatus by the principle of storage cell, mast cells and basophils. Histamine is formed from naturally occurring amino acid L-histidine.
- 3. Histamine stored as protein complexes in mast cells (complexed with heparin) and basophilic granulocytes (complexed with chondroitin). Protein complex stored in secretory granules and released by exocytosis in response to immune (antigen and antibody). ● Storage and release:- ● Biosynthesis of Histamine-:
- 4. ● Receptors and their distribution in Human body Type of receptor Location Mode of action Effect H1 Smooth muscle, vascular endothelial cells, heart, CNS. G protein link to Gq that activate phospholipase C. ● Bronchoconstriction ● gut mortality ● Stimulate sensory nerves H2 Gastric parietal cells, heart, uterus and smooth muscle. G protein link to Gs stimulate adenylcyclase and cAMP ● Increase gastric acid secretion ● Vasodilation H3 CNS with high level in thalmus, cortex and intestine G protein link to Gi inhibit adenylcyclase and cAMP ● Inhibition synthesis and release of histamine ● Modulate release 5HT and Dopamine H4 Express cell of immune system and mast cell, mediate chemotaxis of eosinophils G protein coupled which in cAMP ● Immunomodulation
- 5. ● Classification of Antihistaminic agents 1. First Generation Antihistaminics a. Highly sedative:- i. Diphenhydramine ii. Dimenhydrinate iii. Promethazine iv. Hydroxyzine b. Moderately sedative:- i. Pheniramine ii. Cyproheptadine iii. Cinnarazine c. Mild sedative:- i. Chlorpheniramine ii. Triprolidine iii. Clemastine 2. Second Generation Antihistaminics i. Fexofenadine ii. Cetrizine iii. Ebastine iv. Loratidine v. Levocetrizine vi. Rupatidine Diphenhydramine.Hcl
- 6. H1 Antagonist :- These are agent that block the H1 receptor. They are categorised into first generation and second generation Antihistaminic. 1. Diphenhydramine Hydrochloride Mode of Action :- It displaces histamine from H1 receptor which is a G protein couple receptors. Histamine leads to formation of IP3 and a release of stored Ca++ followed by a cascade of other event. H1 receptor blockade prevents this activity and leads to decrease in Ca++ inside of the cell. Uses :- ● Used in nausea, vomiting and dizziness ● Releave symptom of allergy, hay fever and rashes. Diphenhydramine Hydrochloride
- 7. Synthesis of Diphenhydramine hydrochloride
- 8. 2. Dimenhydrinate Mode of Action :- Dimenhydrinate competitively block H1 receptors preventing the action of histamine on bronchial smooth muscle capillaries and Gastrointestinal (GI) smooth muscle prevent bronchoconstriction and vasodilation, increase capillary permeability. Uses :- ● Used to prevent and treat nausea, vomiting and dizziness. 3. Doxylamine Succinate Mode of Action :- It act as an antagonist of H1 receptor. It antagonises the muscarinic acetylcholine receptor. Uses :- ● Used in relieve symptoms of allergy, hay fever and common cold. Dimenhydrinate Doxylamine Succinate
- 9. 4. Clemastine fumarate ● Used to relieve symptoms of nasal allergies including sneezing, runny nose. Mode of Action :- Selective H1 Antagonist bind to H1 receptor and block the action of histamine. Uses :- Clemastine fumarate 5. Diphenylphyraline Hydrochloride Diphenylphyraline Hydrochloride Mode of Action :- Competes with histamine for binding on the H1 receptor on effector cells relief from allergic symptoms. Uses :- ● Used to treat allergy, hay fever.
- 10. 6. Tripelennamine Hydrochloride Tripelennamine Hydrochloride Mode of Action :- Binds to the H1 receptor and block the action of endogenous histamine relieving the symptoms caused by histamine. Uses :- ● Used to treat sneezing, runny nose, Itching, watery eyes, hives, rashes. 7. Chlorcyclizine Hydrochloride Mode of Action :- It antagonise the histamine receptor and inhibit the histamine release. Tripelennamine Hydrochloride Uses :- ● Used in allergic symptoms like rhinitis, urticaria ● Used in treating hepatitis C.
- 11. 8. Meclizine Hydrochloride Mode of Action :- It inhibit the H1 receptor and prevent the histamine action such as bronchial, Gastrointestinal smooth muscle. Its anticholinergic action ( vasodilation, bronchoconstriction). Meclizine Hydrochloride Uses :- ● Used as antihistaminic to prevent nausea, vomiting and dizziness. ● Used in relieve vertigo. 9. Buclizine Hydrochloride Buclizine Hydrochloride Mode of Action :- Mechanism by which buclizine exerts its antiemetic and antimotion sickness effect is not precisely know but may be related to central anticholinergic actions. Uses :- ● Uses as antivertigo and antiemetic agent
- 12. 10. Chlorpheniramine maleate Mode of Action :- It binds to H1 receptors and inhibit the action of histamine and relieving the negative symptoms produced by histamine. Uses :- ● Used in relieving the symptoms of allergy, hay fever, common cold, rashes, watery eyes, runny nose. Chlorpheniramine maleate 11. Triprolidine Hydrochloride Mode of Action :- It binds to H1 receptors and inhibit the action of histamine and relieving the negative symptoms produced by histamine. Uses :- ● Used in relieve of allergic and non allergic rhinitis, allergic conjunctivitis. Triprolidine Hydrochloride
- 13. ● Synthesis of Triprolidine hydrochloride :-
- 14. 12. Pheniramine Tartrate Mode of Action :- It competes with histamine H1 receptor sites on effector cells. It binds to H1 receptors and inhibit the action of histamine and relieving the negative symptoms produced by histamine. Uses :- ● Used as relieve the symptoms of sneezing, runny nose, Itching, watery eyes, hives, rashes. Pheniramine Tartrate 13. Promethazine Hydrochloride Mode of Action :- It selectively inhibit the peripheral H1 receptors and inhibit the central histaminic receptors depress reticular system causes sedative and hypnotic effect. Uses :- ● Used in curing vertigo ● Used in treating symptoms of allergy. Promethazine Hydrochloride
- 15. ● Synthesis of promethazine Hydrochloride :-
- 16. 14. Trimeprazine Tartrate Mode of Action :- It selectively inhibit the peripheral H1 receptors and inhibit the central histaminic receptors depress reticular system causes sedative and hypnotic effect. Uses :- Trimeprazine Tartrate 15. Cyproheptadine Hydrochloride Cyproheptadine Hydrochloride Mode of Action :- It selectively inhibit the peripheral H1 receptors and inhibit the central histaminic receptors depress reticular system causes sedative and hypnotic effect. Uses :- ● Used as relieve the symptoms of sneezing, runny nose, Itching, watery eyes, hives, rashes. ● Used as relieve the symptoms of sneezing, runny nose, Itching, watery eyes, hives, rashes.
- 17. 16. Azatidine maleate Mode of Action :- It binds to H1 receptors and inhibit the action of histamine and relieving the negative symptoms produced by histamine. Uses :- ● Used in curing vertigo ● Used in treating symptoms of allergy. Azatidine maleate 17. Astemizole Mode of Action :- It binds to H1 receptors and inhibit the action of histamine and relieving the negative symptoms produced by histamine. Uses :- ● Used in relieve of allergic and non allergic rhinitis, allergic conjunctivitis. Astemizole
- 18. 18. Loratidine Mode of Action :- It binds to H1 receptors and inhibit the action of histamine and relieving the negative symptoms produced by histamine. ● Used as relieve the symptoms of sneezing, runny nose, Itching, watery eyes, hives, rashes. Uses :- Loratidine 19. Cetrizine Mode of Action :- It binds to H1 receptors and inhibit the action of histamine and relieving the negative symptoms produced by histamine. Uses :- Cetrizine ● Used as antihistaminic to prevent nausea, vomiting and dizziness. ● Used in relieve vertigo.
- 19. 20. Cromolyn sodium Mode of Action :- It binds to H1 receptors and inhibit the action of histamine and relieving the negative symptoms produced by histamine. Cromolyn sodium Uses :- ● Used to prevent and treat nausea, vomiting and dizziness.
- 20. ● H2 Antagonists H2 receptor blockers are a class of medications that can be used to treat conditions that cause excess stomach acid. These medications are available over the counter and by prescription. Common H2 receptor blockers include: nizatidine (Axid) famotidine (Pepcid, Pepcid AC) cimetidine (Tagamet, Tagamet HB) H2 receptor blockers are most commonly used to treat gastritis, or inflamed stomach, and to treat peptic ulcers. Peptic ulcers are painful sores that form in the lining of the stomach, lower esophagus, or duodenum, which is the first part of the small intestine. They often develop as a result of inflammation and excess stomach acid. Doctors may also recommend H2 receptor blockers to keep peptic ulcers from returning. H2 receptor blockers are also frequently used to relieve the symptoms of gastroesophageal reflux disease (GERD). GERD is a chronic form of acid reflux, which causes acidic stomach contents to flow back up into the esophagus. The frequent exposure to stomach acid can irritate the esophagus and lead to uncomfortable symptoms, such as heartburn, nausea, or trouble swallowing. H2 blockers may also be used to treat less common conditions such as Zollinger-Ellison syndrome, a condition that causes an increased production of stomach acid
- 21. 1. Cimitidine Cimitidine Mode of Action :- Block histamine by competitively binding to H2 receptors ( membrane of gastric parietal cells ). They inhibit the gastric acid secretion Uses :- ● Prevent stomach ulcers ● To treat peptic ulcer disease. 2. Famotidine Mode of Action :- Famotidine Block histamine by competitively binding to H2 receptors ( membrane of gastric parietal cells ). They inhibit the gastric acid secretion Uses :- ● Prevent stomach ulcers ● To treat peptic ulcer disease.
- 22. 3. Ranitidine Mode of Action :- Ranitidine Histamine is released from ECL cells prevent binding to H2 receptors on parietal cell that stimulate acid secretion. Uses :- ● Prevent stomach ulcers ● To treat peptic ulcer disease.
- 23. ● Gastric proton pump inhibitors ● These are irreversible inhibitors of gastric parietal cell proton pump. These enzyme promotes the exchange of H+ or K+ ion which are required for HCl secretion. ● They reduce acid production by blocking enzyme present in the stomach wall. Basic moeity of gastric proton pump inhibitors H+/K+ ATPase proton pump inhibitor inactivate the H+/K+ ATPase pump which is present in apical membrane of parietal cell responsible for acid secretion. They have sulphinyl group in a bridge between substituted benzimidazole and pyridine rings so, They are chemical stable and lipid soluble weak bases. Mode of Action :- Uses :- ● To treat ulcer caused by H. Pylori. ● To reduce the acid secretion. ● Maintain ulcer bed. (This mechanism used for all GPPIs.)
- 24. 3. Omeprazole Omeprazole Uses :- ● To treat excessive production of stomach acid. ● Healing of oesophagus by PPIs. ● Prevent oesophageal cancer. ● To treat heart burn. ● To treat ulcer caused by H. Pylori. 2. Lansoprazol Uses :- ● To treat Gasto Esophageal Reflux Disease (GERD). ● To treat ulcer caused by H. Pylori. Lansoprazol 3. Rabeprazole Uses :- ● To treat Gastro Esophageal Reflux Disease. ● To treat duodenal ulcer caused by H. Pylori. Rabeprazole
- 25. 4. Pantoprazole Uses :- ● Injection of drug to patient having GERD. ● Used to treat zollinger Ellison syndrome. Pantoprazole !!!! Th@nk-you !!!!