Clinical Pharmacology Lecture 5 & 6 Adrenergic Drugs-1 PDF

 COURSE NAME: CLINICAL PHARMACOLOGY COURSE CODE: BSRITCP BSMUTCP COURSE CREDIT HOURS : 02 INSTRUCTOR : MYEDA SAEED  ADRENERGIC AGONISTS AND ANTAGONISTS Learning outcomes Classification of adrenergic agonists Location of adrenergic r...

 COURSE NAME: CLINICAL PHARMACOLOGY COURSE CODE: BSRITCP BSMUTCP COURSE CREDIT HOURS : 02 INSTRUCTOR : MYEDA SAEED  ADRENERGIC AGONISTS AND ANTAGONISTS Learning outcomes Classification of adrenergic agonists Location of adrenergic receptors and their actions Mechanism of action of classified drugs Therapeutic uses Pharmacokinetics Adverse effects and contraindications Classification of adrenergic antagonists Mechanism of action of classified drugs Therapeutic uses and pharmacokinetics Adverse effects and contraindications  ADRENERGIC DRUGS Drugs of Sympathetic Nervous System Adrenergic agonists ( Drugs stimulating the Alpha and Beta receptors) Adrenergic antagonists ( Drugs blocking the Alpha and Beta receptor)  ADRENERGIC AGONISTS Albuterol (Ventolin) Epinephrine (Epipen) Norepinephrine (Levophed) Isoproterenol (Isuprel) Dobutamine (Dobutrex) Formoterol (Foradil) Salmeterol (Serevent diskus) Cocaine  Epinephrine Epinephrine is synthesized in adrenal medulla and released, along with small quantities of norepinephrine, into the bloodstream. Epinephrine interacts with both α and β receptors.  Actions: The major actions of epinephrine are on the cardiovascular system. Epinephrine strengthens the contractility of the myocardium. Epinephrine causes powerful bronchodilation by acting directly on bronchial smooth muscle.  Pharmacokinetics: Epinephrine has a rapid onset and a brief duration of action (due to rapid degradation).  Therapeutic uses: Bronchospasm: Epinephrine is the primary drug used in the emergency treatment of any condition of the respiratory tract when bronchoconstriction has resulted. Thus, in treatment of acute asthma and anaphylactic shock, epinephrine is the drug of choice. Cardiac arrest: Epinephrine may be used to restore cardiac rhythm in patients with cardiac arrest. Adverse effects: CNS disturbances: Epinephrine can produce adverse CNS effects that include anxiety, fear, tension, headache, and tremor. Cardiac arrhythmias Pulmonary edema  Norepinephrine Pharmacokinetics: Norepinephrine may be given IV for rapid onset of action. The duration of action is 1 to 2 minutes. It is a potent vasoconstrictor. Therapeutic uses: Norepinephrine is used to treat shock, because it increases blood pressure. Adverse effects: CNS disturbances: Nor Epinephrine can produce adverse CNS effects that include anxiety, fear, tension, headache, and tremor. Cardiac arrhythmias Pulmonary edema  Isoproterenol Isoproterenol stimulates both β1- and β2-adrenergic receptors. It Increases cardiac output Therapeutic uses: Isoproterenol can be used to stimulate the heart in emergency situations. Adverse effects: CNS disturbances: Isoproterenol can produce adverse CNS effects that include anxiety, fear, tension, headache, and tremor. Cardiac arrhythmias Pulmonary edema  Dobutamine Actions: It increases cardiac rate and output. Therapeutic uses: Dobutamine is used to increase cardiac output in acute congestive heart failure Adverse effects: Tachyarrhythmia  Albuterol Short-acting β 2 agonist Therapeutic use: Primarily as bronchodilator and administered by a metered-dose inhaler. Adverse effects: Tremors and restlessness.  Salmeterol and formoterol Salmeterol and formoterol are b2-adrenergic agonists that are long-acting bronchodilators. It provides sustained bronchodilation over 12 hours. Therapeutic use: Salmeterol and formoterol are the agents of choice for treating nocturnal asthma in symptomatic patients taking other asthma medications Adverse effects: These agents should not be used in excess. Death has been reported in overuse of the drug.  Cocaine Is a widely available and highly addictive drug Therapeutic uses: cocaine is applied topically as a local anesthetic during eye, ear, nose, and throat surgery. Adverse effects: Depression  Adrenergic antagonists α BLOCKERS Phenoxybenzamine (Dibenzyline) Phentolamine (Regitine) Prazosin (Minipress) Terazosin (Hytrin)  β BLOCKERS Esmolol (Brevibloc) Nadolol (Corgard) Propranolol (Inderal LA) Timolol (Betimol)  α BLOCKERS Phenoxybenzamine The actions of phenoxybenzamine last about 24 hours after a single administration. Therapeutic uses: Phenoxybenzamine is used in the treatment of pheochromocytoma Adverse effects: Postural hypotension, Nausea, Vomiting  Phentolamine Produces a competitive block of α1 and α2 receptors. This drug’s action lasts for approximately 4 hours after a single administration. Therapeutic use: used for the short-term management of pheochromocytoma. Adverse effects: postural hypotension  β blockers Propranolol Propranolol blocks both β 1 and β 2 receptors. Actions: Vasoconstriction Bronchoconstriction  Pharmacokinetics: It is subjected to first-pass effect, and only about 25 percent of an administered dose reaches the circulation  For Example, If 40 mg of propranolol is administered to a hypertensive patient, how much of the administered dose will reach systemic circulation? Calculation: 25/100 X 40 mg = 10 mg  Therapeutic effects: Hypertension Angina pectoris Heart attack Adverse effects: Bronchoconstriction Arrhythmias Depression  Timolol and nadolol These agents are more potent than propranolol. Nadolol has a very long duration of action. Therapeutic use : Used topically in the treatment of chronic glaucoma and, occasionally, for treatment of hypertension. Adverse effects: Bronchoconstriction Arrhythmias  REFERENCES Lippincott’s Pharmacology 5th edition Bertram G. Katzung basic and clinical pharmacology 13th edition WebMD Drugs.com Medscape