{"id":6548,"date":"2024-11-16T12:25:52","date_gmt":"2024-11-16T12:25:52","guid":{"rendered":"https:\/\/workhouse.sweetdishy.com\/?p=6548"},"modified":"2024-11-16T12:25:52","modified_gmt":"2024-11-16T12:25:52","slug":"cholinergic-drugs","status":"publish","type":"post","link":"https:\/\/workhouse.sweetdishy.com\/index.php\/2024\/11\/16\/cholinergic-drugs\/","title":{"rendered":"CHOLINERGIC DRUGS"},"content":{"rendered":"\n<p><br>Cholinergic drugs are also called parasympathomimetics because their effect mimics the effect<br>of parasympathetic nerve stimulation. Administration of these drugs will result in an increase in<br>the parasympathetic activities in the systems innervated by cholinergic nerves.<br>There are two groups of cholinergic drugs:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>Direct-acting: bind to and activate muscarinic or nicotinic receptors (mostly both) and<br>include the following subgroups:<br>a. Esters of choline: methacholine, carbachol, betanechol<br>b. Cholinergic alkaloids: pilocarpine, muscarine, arecoline, nicotine<\/li>\n\n\n\n<li>Indirect-acting: inhibit the action of acetylcholinesterase enzyme<br>a. Reversible: neostigmine, physostigmine, edrophonium<br>b. Irreversible: Organophosphate compounds; echothiophate<br>The actions of acetylcholine may be divided into two main groups: &#8211;<\/li>\n\n\n\n<li>Nicotinic actions- those produced by stimulation of all autonomic ganglia and the<br>neuromuscular junction<\/li>\n\n\n\n<li>Muscarinic actions- those produced at postganglionic cholinergic nerve endings<\/li>\n<\/ol>\n\n\n\n<p><strong>ESTERS OF CHOLINE<br>ACETYLCHOLINE <\/strong>is the prototypical cholinergic agent. It functions as a neurotransmitter at all<br>cholinergic sites in the body; because of its unique pharmacokinetic properties, it has never<br>been used in medical therapeutics; the discussion which follows is for academic exercise.<br><strong>Pharmacokinetics<\/strong><br>Acetylcholine is poorly absorbed from the gastric mucosa; therefore it is ineffective if given<br>orally. The recommended way of administration is parenteral. In the blood it is rapidly<br>hydrolyzed by the enzyme cholinesterase into acetic acid and choline; this makes its duration of<br>action very short and unreliable for therapeutic purposes.<br><strong>Pharmacodynamics<\/strong><br>As mentioned earlier it has two types of actions: nicotinic and muscarinic; the muscarinic actions<br>are of main interest and are discussed below.<br><\/p>\n\n\n\n<p><strong>Blood vessels\u00c6 vasodilator<\/strong><br><strong>Blood pressure\u00c6<\/strong> falls because of the effect on the heart and blood revels<br><strong>i) Gastrointestinal tract<br><\/strong>It stimulates the tone and motility of the Gl tract but the sphincters will be relaxed<br><strong>ii) Urinary tract<br><\/strong>It stimulates the detrusor muscle and relaxes the internal urethral sphincter resulting in<br>evacuation of bladder<br>iii) <strong>Bronchioles<\/strong><br>It increase bronchial secretion and brings about bronchoconstriction<br>iv) Eye- It has two effects- miosis and accommodation for near objects because of stimulation of<br>the constrictor pupillae and ciliary muscles respectively.<br>v) Exocrine glands- it stimulates salivary, gastric, bronchial, lachrymal and sweat gland<br>secretions.<br>SYNTHETIC CHOLINE ESTERS. These are synthetic derivatives of choline and include<br>metacholine, carbachol and beta<\/p>\n\n\n\n<p><strong>CARBACHOL<\/strong><\/p>\n\n\n\n<p><strong>Pharmacokinetics<br><\/strong>It is completely absorbed from the gastro intestinal tract and is stable towards hydrolysis by<br>cholinesterase enzyme; therefore it can be given both orally and parenteraly with almost similar<br>dosage.<br><strong>Pharmacodynamics<br><\/strong>It has similar actions to those of acetylcholine with pronounced effects on the gastro intestinal<br>tract and the urinary bladder<br>Indications<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Glaucoma<\/li>\n\n\n\n<li>Retention of urine (postoperative)<\/li>\n\n\n\n<li>Paralytic ileus<\/li>\n<\/ul>\n\n\n\n<p><strong>BETANECHOL<\/strong><br>This drug is similar to carbachol in all parameters, i.e., pharmacokinetics, pharmacodynamics<\/p>\n\n\n\n<p>and clinical indications; it has a better advantage over carbachol because it has fewer side<br>effects as a result as lack of nicotinic actions.<br>Contra indications to the use of choline esters<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>Bronchial asthma because they may induce bronchial constriction and increase bronchial<br>secretions<\/li>\n\n\n\n<li>Hyperthyroidism because of the danger of inducing atrial fibrillation<\/li>\n\n\n\n<li>Peptic ulcer disease because of the increase in gastric acid secretion<\/li>\n\n\n\n<li>Coronary insufficiency because the hypertension produced will further compromise coronary<br>blood flow<\/li>\n\n\n\n<li>Mechanical intestinal and urinary outlet obstruction<br>CHOLINERGIC ALKALOIDS<\/li>\n\n\n\n<li>Those with chiefly nicotinic actions include nicotine, lobeline etc.<\/li>\n\n\n\n<li>Those with chiefly muscarinic actions include muscarine, pilocarpine, etc.<br>PILOCARPINE<br>Pharmacokinetics<br>This drug is readily absorbed from the gastrointestinal tract and it is not hydrolyzed by<br>cholinesterase enzyme. It is excreted partly destroyed and partly unchanged in the urine.<br>Pharmacodynamics<br>The drug directly stimulates the muscarinic receptors to bring about all the muscarinic effects of<br>acetylcholine.<br>Indications<\/li>\n<\/ol>\n\n\n\n<p><strong>ANTICHOLINESTERASE DRUGS<\/strong><br>The commonly used cholinesterase inhibitors fall into three chemical groups:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>Simple alcohols bearing quaternary amines, e.g., edrophonium<\/li>\n\n\n\n<li>Carbamate and related quaternary or tertiary amines, e.g., neostigmine, physostigmine<\/li>\n\n\n\n<li>Organic derivatives of phosphates, e.g., isofluorophate, echothiophate<\/li>\n<\/ol>\n\n\n\n<p><strong>PHYSOSTIGMINE<\/strong><br><strong>Pharmacokinetics<\/strong><br>This drug is completely absorbed from the gastrointestinal and is highly distributed throughout<br>the body; it can pass the blood brain barrier.<br><strong>Pharmacodynamics<\/strong><br>Inhibits the enzyme cholinesterase; therefore, it increases and prolongs the effect of<br>endogenous acetylcholine at the different sites.It has no direct effect on cholinergic receptors.<br><strong>Indications<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Glaucoma<\/li>\n\n\n\n<li>Atropine over dosage<br><strong>NEOSTIGMINE<\/strong><br>Pharmacokinetics<br>This drug is poorly absorbed from the gastro intestinal tract and is poorly distributed throughout<br>the body; it cannot pass the blood brain barrier.<br><strong>Pharmacodynamics<\/strong><br>Just like physostigmineit inhibits cholinesterase enzyme; but unlike physostigmine, it has a<\/li>\n\n\n\n<li>direct nicotinic action on skeletal muscles.<\/li>\n\n\n\n<li><strong>Indications<\/strong><\/li>\n\n\n\n<li>Myasthenia gravis<\/li>\n\n\n\n<li>Paralytic Ileus<\/li>\n\n\n\n<li>Reversal of effect of muscle relaxants, e.g. tubocurarine<\/li>\n\n\n\n<li>Post operative urine retention<br><strong>Organophosphates<\/strong> such as echothiophate, isofluorophate, etc. combine with cholinesterase<br>irreversibly and thus hydrolysis is very slow.<br>They may be used in glaucoma. Other organophosphates like parathion and malathion are used<br>as insecticides. Poisoning with organophosphates is an important cause of morbidity and<br>mortality all over the world. It usually results from:<\/li>\n\n\n\n<li>Occupational exposure as in persons engaged in spraying insecticides,<\/li>\n\n\n\n<li>Accidental exposure, and<\/li>\n\n\n\n<li>Ingestion of any of these compounds with suicidal intent.<\/li>\n<\/ul>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Cholinergic drugs are also called parasympathomimetics because their effect mimics the effectof parasympathetic nerve stimulation. Administration of these drugs will result in an increase inthe parasympathetic activities in the systems innervated by cholinergic nerves.There are two groups of cholinergic drugs: ESTERS OF CHOLINEACETYLCHOLINE is the prototypical cholinergic agent. It functions as a neurotransmitter at allcholinergic [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":6502,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[690],"tags":[],"class_list":["post-6548","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-drugs-acting-on-autonomic-nervous-system"],"jetpack_featured_media_url":"https:\/\/workhouse.sweetdishy.com\/wp-content\/uploads\/2024\/11\/drugs.png","_links":{"self":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts\/6548","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/comments?post=6548"}],"version-history":[{"count":1,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts\/6548\/revisions"}],"predecessor-version":[{"id":6549,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts\/6548\/revisions\/6549"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/media\/6502"}],"wp:attachment":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/media?parent=6548"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/categories?post=6548"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/tags?post=6548"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}