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[Fr. café, coffee + -ine]
C8H10N4O2; an alkaloid present in coffee, chocolate, tea, many cola drinks, cocoa, and some over-the-counter medicines. The amount of caffeine in beverages varies from 40 to 180 mg in 6 oz (180 mL) of coffee, from 2 to 5 mg in decaffeinated coffee, and from 20 to 110 mg in 5 oz (150 mL) of tea. The caffeine in cola drinks ranges from 30 to 90 mg in a 360-mL (12-oz) serving. The pharmacological action of caffeine includes stimulation of the central nervous system (CNS), improvements in respiratory function, increases in the secretion of gastric acid and pepsin, elevation of free fatty acids in plasma, diuresis, increase in the basal metabolic rate, decrease in total sleep time, and possible increase in blood glucose level. Caffeine is used in neonatal intensive care to facilitate and sustain successful weaning from mechanical ventilation. It is considered an ergogenic aid in athletics because it tends to enhance endurance and improves reaction time. Adverse effects include drug dependence and withdrawal in some habitual users.
SEE: caffeine intoxication; SEE: caffeine withdrawal headache.

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