Lecture 2: Sympathetic Nervous System Pharmacology PDF

by Dr/ Eman Aboelyazeed Lecturer in Clinical Pharmacology Pharmacological actions of Due to adrenergic receptors sympathomimetics: stimulation  Indications of sympathomimetics: “NGBHA” 1- Allery and anaphylactic shock e.g. adrenaline (IM). 2-...

by Dr/ Eman Aboelyazeed Lecturer in Clinical Pharmacology Pharmacological actions of Due to adrenergic receptors sympathomimetics: stimulation  Indications of sympathomimetics: “NGBHA” 1- Allery and anaphylactic shock e.g. adrenaline (IM). 2- CVS: Hypotension and shock e.g. dobutamine, phenylephrine,noradrenaline. 3- Congestive heart failure e.g. dobutamine. 4- Cardiac arrest e.g. adrenaline intracardiac 5-Heart block e.g. isoprenaline. 6- With local anesthesia e.g. adrenaline. 7- Respiratory: Bronchial asthma e.g. Salbutamol, terbutaline. 8- Eye: Glaucoma e.g. adrenaline. 9- CNS: Narcolepsy and obesity e.g. amphetamine. Preparations: Adrenaline (inhalation, SC.) noradrenaline (IV) isoprenaline (inhalation, Sl., IV, oral) Salbutamol, terbutaline (inhalation, oral). Adverse Tachycardia/ arrhythmias. effects: Angina. Hypertension. Ischemia-necrosis. Restlessness. Tremors. Insomnia anxiety. Contraindications: Hypertension. Angina. Digitalization. Thyrotoxicosis. Halothane anesthesia. Beta-adrenergic blockers  Pharmacological actions Heart: Decrease all properties of the heart including decrease heart rate, contractility, cardiac output (COP) , and automaticity. Blood vessels: Decrease blood pressure by decrease COP, central sympathetic discharge to CVS, decrease renin release, some beta blockers have vasodilator effect. Respiratory system: Bronchospasm. Eye: Decrease IOP. Metabolic effect: disturbance decrease glycogenolysis so increase hypoglycemia of insulin and other antidiabetic drugs, inhibit lipolysis, increase plasma triglycerides. Indications: Cardiac Non-cardiac Hypertension Gastrointestinal bleeding in hepatic cirrhosis Angina pectoris Hyperthyroidism Myocardial infarction Glaucoma Cardiac arrhythmias. Anxiety and tremors. Acute dissecting aortic aneurysm Hypertrophic obstructive cardiomyopathy. Adverse effects: (BAD FISH) B→ Bradycardia, Bronchospasm. A→ AV block/arrhythmias. D→ Depression, Dizziness. F→ Fatigue. I→ Impotence. S→ signs of hypoglycemia masked H→ hypotension Contraindications: (ABCDEF) A→Asthma, allergy. B→ Heart Block, low blood pressure. C→COPD (chronic obstructive pulmonary disease). D→Diabetes mellitus, Depression. E→ electrolyte disturbance (hyperkalemia). F→Failure of heart. Preparations: 1-Propranolol is a nonselective B-antagonist, act on both B1 and B2 receptors, potent, passes to CNS. 2-Metoprolol, atenolol, acebutolol: selective B-antagonist, atenolol and acebutolol do not pass to CNS. 3- Nadolol: longer duration of action than other B-blockers. 4- Timolol: nonselective B-blockers, has excellent ocular effects. 5- Pindolol: nonselective B-blockers with partial agonist activity. Evaluate apical-radial pulse blood pressure electrolytes (k+) blood glucose, cholesterol and triglycerides levels. Teach avoiding abrupt withdrawal avoiding driving or operating hazardous machinery. Rapid Dental Hint The use of local anesthetics + epinephrine for patients taking nonselective beta blockers (e.g., propranolol) →severe elevations in blood pressure Cause: inability of epinephrine to bind to the β2 receptors and consequently, cause an exaggerated effect at the α1receptors. Therefore, limit the amount of epinephrine ‫ياالقوموا امشوا‬