Class (23) Alpha Adrenergic Receptor Blockers |Medicinal Chemistry 01 | Alpha Receptor Blockers

Download the "Solution Pharmacy" Mobile App to Get All Uploaded Notes, Model Question Papers, Answer Papers, Online Tests and other GPAT Materials - https://play.google.com/store/apps/de... Solution Pharmacy will cover this syllabus of medicinal chemistry 01 for B.Pharmacy 4th semester Unit 02 – (01) Drug acting on the autonomic nervous system (02) Adrenergic neurotransmitters – biosynthesis and catabolism of catecholamine, adrenergic receptors, alpha-adrenergic receptor and beta-adrenergic receptor and the distribution of alpha and beta-adrenergic receptors (03) Sympathomimetic agents structure-activity relation (SAR) of sympathomimetic agents like direct acting – Nor-epinephrine, epinephrine, Phenylephrine, dopamine, methyldopa, clonidine, dobutamine, isoproterenol, terbutaline, salbutamol, bitolterol, naphazoline, oxymetazoline, and xylometazoline. (04) Indirect-acting agents – Hydroxy amphetamine, Pseudoephedrine, propylhexedrine, (05) Agents with a mixed mechanism (06) Adrenergic antagonist – (07) Alpha adrenergic blocker, tolazoline, Phentolamine, Phenoxybenzamine, prazosin, dihydroergotamine, mtyhlesergide. (08) Beta-adrenergic blockers – SAR of beta blockers, Propranolol, Metipranolol, Atenolol, Bisoprolol, esmolol, metoprolol, labetalol, carvedilol Selective a- blockers Prazosin Prazosin is quinazoline alpha 1 - blocker. As a result of its greater alpha 1 - receptor selectively, the quinazoline class of a-blockers exhibits greater clinical utility. Mechanism of action: It has potent alpha 1 - adrenoreceptor blocking activity. It is potent and effective antihypertensive agent and maybe usefully combined with the beta- adrenoreceptor blockers, and thiazide diuretics. SAR 1. Structurally prazosin consists of three components - the quinazolme ring the piperazine ring and acyl moieity 2. The 4- amino group on quinazolin ring is very important for a receptor affinity. 3. The piperazine moiety can be replaced with other heterocyclic moieties (eg piperidine moiety) without loss of affinity. 4. The nature of the acyl group has a significant effect on the pharmacokinetic properties Therapeutic Uses: Used in the treatment of hypertension and heart attack. Also, help to improve the urination flow rate Dihydroergotamine Ergot is a parasitic fungus on rye and certain grains. Two major actions of ergot alkaloids are: to stimulate smooth muscles and block alpha-adrenoceptors. Mechanism of action Dihydroergotamine increases the a - blocking potency and reduces the smooth muscle stimulant activity. Metabolism Metabolism of dihydroergotamine by a cytochrome P-450 similar to that involved in the metabolism of macrolide antibiotics. Therapeutic uses: Dihydroergotamine is used to treat migraine. The pain of migraine and vascular headache is associated with vasodilation, and edema, hydroergotamine is effective due to its action on vascular smooth muscle and should be given during vasoconstriction phase. Methysergide It is structurally identical to methyl ergonovine except methyl group to indole nitrogen. All ergot alkaloids are amide derivative of lysergic acid but diethyl amine lysergic acid produce profound hallucinatory effect. Mechanism of action Methysergide interacts with serotonin (5-HT) receptors. Its therapeutic effect in migraine prophylaxis has been associated with its antagonism at the 5-HT2B receptor. It is an antagonist at the 5-HT2C receptor, while at the 5-HTIA receptor it serves as a partial agonist. It is known to have partial agonist effects on some of the other 5-HT receptors as well. It antagonizes the effects of serotonin in blood vessels and gastrointestinal, smooth muscle, but has few of the properties of other ergot alkaloids. Therapeutic uses: It is used to treat headache, carcinoid syndrome and serotonin syndrome. E-Mail for official and other work - solutionpharmacy@gmail.com #solutionpharmacy #Pharmacologyclass #Pharmacognosyvideos #GPAT