CNS Pharmacology - Chapter 10 PDF

Part 1 1: CNS S Stimullants Classiffication: █ RES SPIRATOR RY STIMUL LANTS (A ANALEPTIC CS) Definittion: drugss that stimu ulate the d...

Part 1 1: CNS S Stimullants Classiffication: █ RES SPIRATOR RY STIMUL LANTS (A ANALEPTIC CS) Definittion: drugss that stimu ulate the d depressed respiratory y center (R RC). Classiffication: Spe ecific analleptics:  Naloxon and a nalorph hine → usedd to treat opiates o res spiratory d depression.  Flumazenil → used to o treat ben nzodiazepin nes toxicity y. Non n-specific c analeptic cs:  Direct RC stimulatio on: e.g. Xa anthines (c caffeine, theophyllinne) – Etham mivan - Heptamino ol. They an ntagonize tthe GABA--mediated RC depresssion.  Indirect RC C stimulation (reflex)): e.g. Nico otine and lobeline. T They stimulate RC indirectly through t stiimulation o of the chem morecepto ors in the ccarotid bod dy.  Both (direcct and indirect): Nikeethamide - Doxapram m Therap es: all case peutic use es of RC ddepression n (postanaesthetic, C CNS depre essants, COPD and some premature e babies) 327  Adverse effects – Tachypnea, tachycardia and hypertension. – High doses can cause convulsions. Contraindications – Epilepsy (to avoid CNS stimulation). – Severe hypertension, arrhythmia or IHD (to avoid cardiac arrhythmia). – Thyrotoxicosis. – Severe bronchial asthma. █ PSYCHOMOTOR STIMULANTS Definition: drugs that induce euphoria with increased motor activity. Classification Amphetamine and related drugs: see ANS Cocaine – Cocaine inhibits tissue uptake of catecholamines. – Behavioral effects of cocaine are very similar to amphetamine. – Cocaine is used topically as a local anesthetic eye drops. Xanthines: see respiratory pharmacology. Antidepressants: see later. █ PSYCHOTOMIMETIC DRUGS (HALLUCINOGENS) Definition: drugs that affect thought, perception and mood with no effect on motor activity. They have no clinical applications but important for drug abuse. Examples and Mechanisms  LSD (Lysergic acid diethylamide): It stimulates central 5-HT receptors and affects catecholamine action → severe hallucinations and delusions resembling acute schizophrenia.  Cannabis (hashish, marijuana): It acts on cannabinoid receptors in the CNS (CB1) causing loss of judgment of time & place and dream-like state. It does not cause physical dependence but psychological dependence. CB2 receptors are found in peripheral tissue and immune system.  Phencyclidine: It stimulates -opioid receptors and blocks the NMDA receptors and may interact with other neurotransmitter systems. 328