Associate Professor in Pharmacology, AUTACOIDS Dr A. Shyam Sundar, Associate Professor in Pharmacology, University of Nizwa, Sultanate of Oman

UNIT 9: Autacoid Pharmacology UNIT INSTRUCTIONAL OUTCOMES: At the end of this unit, the student should be able to, List names of autacoids of pharmacological interest State vital information about the drugs act by modifying autacoids Apply pharmacological knowledge gained in the clinical scenario.

Overview Autacoids are local hormones which are produced locally, exert their actions locally and degraded locally. They can be derivatives of 1. Amines (Histamine and Serotonin). 2. Peptides (Bradykinin,Angiotensin). 3. Lipids (Prostaglandins, Leukotrienes and Platelet activating factor) Histamine , Serotonin will be discussed in detail in this lecture. We have already discussed the actions of Angiotensin in the chapter anti-hypertensive drugs and Leukotrienes were discussed during anti asthmatic lectures.

HISTAMINE- RECEPTORS LOCATION AND ACTIONS Lippincott's Illustrated Reviews: Pharmacology, 4th Edition.

HISTAMINE RECEPTOR BLOCKERS AND THEIR CLINICAL USES H1 receptor blockers: First generation: Azelastine Chlorpheniramine cyproheptadine Diphenhydramine Hydroxyzine Phenindamine Promethazine Tripelenamine Second generation : Cetirizine Desoratadine Fexofenadine Loratadine Clinical uses of H1 receptor blockers Urticaria Hypersensitivity reactions Hypersensitive reactions: An inappropriate and excessive reaction to an allergen (as pollen or dust or animal hair or certain foods); severity ranges from mild allergy to severe systemic reactions leading to anaphylactic shock Urticaria: An itchy skin eruption… Anand, M.D. Ramachandran, Pharmacology Recall, Second Edition, Wolters Kluwer

ADRs of H1 antagonists Vertigo: A sensation of dizziness Drowsiness: Dull with sleepiness Dizziness: Having a whirling(to rotate/spin) sensation and tendency to fall Lippincott's Illustrated Reviews: Pharmacology, 4th Edition.

HISTAMINE RECEPTOR BLOCKERS AND THEIR CLINICAL USES Peptic Ulcer Zollinger-Ellison Syndrome Acute Stress ulcers Gastroesophagal reflex disease Lippincott's Illustrated Reviews: Pharmacology, 4th Edition.

SEROTONIN Serotonin is an indole ethylamine found in both plant and animal tissues. 90% of serotonin is present in GI tract and 10% present in CNS. Serotonin exert its action through seven major 5-HT cell membrane receptor subtypes. Physiological actions of Serotonin: Anand, M.D. Ramachandran, Pharmacology Recall, Second Edition, Wolters Kluwer

Sumatriptan is a serotonin agonist used to treat migraine headaches. Dizziness, Neck pain and muscle weakness are the adverse effects of sumatriptan. SEROTONIN ANTAGONISTS AND THEIR CLINICAL USES Anand, M.D. Ramachandran, Pharmacology Recall, Second Edition, Wolters Kluwer

PROSTAGLANDINS Therapeutic Uses of Prostaglandins: Impotence Several of the naturally occurring prostaglandins, such as dinoprost , dinoprostone , and carboprost , find use as abortifacients . Misoprostol in combination with methotrexate is particularly effective in terminating pregancy in the first trimester. Misoprostol is a synthetic prostaglandin E1 analog used to inhibit the secretion of hydrochloric acid in the stomach. It produces inhibition of gastric acid and pepsin secretion and enhances mucosal resistance to injury. Misoprostol is particularly useful in patients with gastric ulcer who are chronically taking nonsteroidal anti-inflammatory agents Therapeutic Uses of Prostaglandins: Alprostadil injected into the corpus cavernosum of the penis provides effective treatment of some forms of male impotence. Impotence Anand, M.D. Ramachandran, Pharmacology Recall, Second Edition, Wolters Kluwer