Ans Medications PDF

ADRENERGIC MEDICATIONS  Adrenergic agonists A. Direct acting : 1. Alpha agonists 2. Beta agonists – The direct acting drugs can also be divided in to catecholamine and non- catecholamine B. Indirect acting 1. Releasers 2. Reuptake inhibitors  A. Direct act...

ADRENERGIC MEDICATIONS  Adrenergic agonists A. Direct acting : 1. Alpha agonists 2. Beta agonists – The direct acting drugs can also be divided in to catecholamine and non- catecholamine B. Indirect acting 1. Releasers 2. Reuptake inhibitors  A. Direct acting I. Catecholamines 1. Epinephrine: – α (all types) and β (all types) agonist used to treat anaphylaxis and with local anesthesia – Side effect: hyperglycemia, arrhythmias, hypertension 2. Norepinpherine: – α (all types) and only β1 agonist used to treat neurogenic shock, last resort therapy in shock patient 3. Dopamine: – Stimulate D1, β1 and α1 receptors 4. Dobutamine: – β 1 agonist.  II. Noncatecholamines α1 agonist: Phenylephrine α2 agonist: clonidine Β1 agonist: No drug (just catecholamines) β2 agonist: salbutamol & ritodrine  B. Indirect acting sympathomimetic Indirect acting sympathomimetic drugs cause: 1. Norepinephrine release from presynaptic terminals or 2. Inhibit the uptake of norepinephrine. They potentiate the effect of NE ,but do not directly affect post-synaptic receptors. Amphetamine, Ephedrine and Pseudoephedrine.  Adrenergic antagonist (sympatholytic)  Adrenoceptors blocking agents 1. Agents block both α and β receptors Labetalol and carvedilol 2. Non selective α blocking agents: Phenoxybenzamine 3. Selective α1 blockers. Prazosin, terazosin, doxazosin and tamsulosin 4. Non -selective beta antagonist Block both types of beta receptors Propranolol, timolol and nadolol. 5. Selective beta 1 antagonist Acebutolol, atenolol, metoprolol Cholinergic Agonists  Cholinergic agonists A. Direct acting: 1. Acetylcholine 2. Bethanechol 3. Carbachol 4. Pilocarpine B. Indirect acting: 1. Reversible 2. Irreversible  Uses: Only few muscarinic agonists are used in clinical practice Pilocarpine is used as an eye drops to treat glaucoma because it reduces the intraocular pressure. Bethanechol used to stimulate bladder emptying  B. Indirect acting muscarinic agonists (reversible anticholinesterase) Neostigmine,Pyridostigmine,Physostigmi ne, Donepezil Anticholinesterases drugs: these drugs inhibit Acetylcholinesterase (true cholinesterase) and Butyrylcholinesterase (pseudocholinesterase) equally. The inhibited Acetylcholinesterase and Butyrylcholinesterase in the peripheral system can be reversed by pralidoxime.  Clinical uses of reversible anticholinesterase It is use to reverse the action of non- depolarizing neuromuscular blockers. Treatment of myasthenia gravis Treatment of Glaucoma. First line in treatment of Alzheimer's disease. Cholinergic Antagonist  1. Atropine Uses: Used clinically to cause mydriasis in and cycloplegia to facilitate examination of the eye in ophthalmology GIT relaxant so it is used as antispasmodic Used for children with involuntary enuresis In the heart it is used for treatment of heart block It can also be used to produce drying of secretion in bronchi before anesthesia It is also used as an antidote for cholinergic agonist. Side effects CNS stimulation, restlessness, confusion and hallucination Increase in body temperature because it inhibit sweating Dry eye, dry mouth, blurred vision "sandy eyes”, tachycardia, urinary retention and constipation. 2. Scopolamine ( Hyosine ) USES: antispasmodic and for motion sickness It blocks the short term memory (amnesic drug) so it is important adjunct drug in anesthetic procedure. In contrast to atropine this drug cause sedation and euphoria. This drug is subject for abuse.  3. Ipratropium Used as bronchodilator in asthmatic patients When given by inhaler it acts locally in the lung producing no adverse systemic effects  Drugs affecting nicotinic receptors 1. At Neuromuscular junction (Nm) A. Neuromuscular junction blockers 2. At autonomic ganglia (Nn) A. Ganglionic blocking agents B. Ganglion stimulating agents Neuromuscular Junction Muscle Relaxants Blockers (Neuromuscular blocking drugs) Neuromuscular blocking drugs block cholinergic transmission between motor nerve endings & the nicotinic receptors on the neuromuscular end plate of skeletal muscle.  Muscle Relaxants 1. Depolarizing muscle relaxant – Succinylcholine 2. Nondepolarizing muscle relaxants A.Long acting Pancuronium B. Intermediate acting Atracurium C. Short acting Mivacurium  1. Depolarizing Muscle Relaxant (Non-Competitive blockers) Succinylcholine Mechanism of action: – Continuous end-plate depolarization causes muscle relaxation Clinical use: – Most often used to facilitate intubation –  2. Non depolarizing Muscle Relaxants (Competitive Mechanism of action: blockers) – Compete with Acetylcholine at the binding sites – Do not depolarized the motor endplate – Act as competitive antagonist – Act at presynaptic sites, prevent movement of Acetylcholine to release sites Good luck