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CLINICAL PHARMACOLOGY 2003 (PART 12B)

Chronic consumption For benefits of chronic alcohol consumption, see page 187. Central nervous system. The development of dependence on alcohol appears to involve alterations in central nervous system neurotransmission. The acute effect of alcohol is to block NMDA receptors for which the normal agonist is glutamate, the main excitatory transmitter in the brain. Chronic exposure increases the number of NMDA receptors and also 'L type' calcium channels, while the action of the (inhibitory) GABA neurotransmitter is reduced. The resulting excitatory effects may explain the anxiety, insomnia and craving that accompanies sudden withdrawal of alcohol (and may explain why resumption of. | 10 NONMEDICAL USE OF DRUGS SECTION For benefits of chronic alcohol consumption see page 187. Central nervous system. The development of dependence on alcohol appears to involve alterations in central nervous system neurotransmission. The acute effect of alcohol is to block NMDA receptors for which the normal agonist is glutamate the main excitatory transmitter in the brain. Chronic exposure increases the number of NMDA receptors and also L type calcium channels while the action of the inhibitory GABA neurotransmitter is reduced. The resulting excitatory effects may explain the anxiety insomnia and craving that accompanies sudden withdrawal of alcohol and may explain why resumption of drinking brings about relief perpetuating dependence . Malnutrition. With heavy continuous drinking subjects take all the calories they need from alcohol cease to eat adequately and develop deficiency of B group vitamins particularly. The malnutrition complicates the long-term effects of alcohol itself. Organ damage. Chronic heavy alcohol use is associated with hepatic cirrhosis deteriorating brain function psychotic states dementia seizures Wernicke s encephalopathy episodes of loss of memory peripheral neuropathy and separately myopathy including cardiomyopathy cancer of the upper alimentary and respiratory tracts many alcoholics also smoke heavily and this contributes hepatic carcinoma and breast cancer in women chronic pancreatitis cardiomyopathy bone marrow depression including megaloblastosis due to the alcohol and to alcohol-induced folate deficiency deficiency of vitamin K-dependent blood clotting factors due to liver injury psoriasis multiple effects on the hypothalamic pituitary endocrine system endocrine investigations should be interpreted cautiously Dupuytren s contracture. Hypertension. Heavy chronic use of alcohol is an important cause of hypertension and this should always be considered in both diagnosis and management. Cessation of use may be sufficient to eliminate or