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Caffeine

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Caffeine

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  1. Caffeine Chapter 8

  2. Caffeine • Most used drug in the world • An alkaloid belonging to a class of compounds called METHYLXANTHINES • Caffeine • Theophylline • Theobromine

  3. History of Caffeine • Huge history of use • Tea dates back to 2737 B.C. in Chinese legend • Coffee uncertain, but cultivated in Ethiopia in 575 A.D. • clearly beans chewed & probably brewed way before • Tea comes from Far East • Coffee from the Middle East/North Africa

  4. History • Both coffee and tea historically used as religious drinks • Over time, became widely consumed throughout all levels of society • Played invaluable role in history of world • importance in European commerce and colonial development

  5. COFFEE • 1st coffeehouse in Constantinople in 1554 • England • First coffee house – Oxford - 1650 • 1700s London - 2000 coffee houses • Heavy association with political turmoil • Governments frequently tried to ban coffee houses, thinking they could suppress revolution

  6. COFFEE • Growth of coffee houses in 1700s played role in reducing gin epidemic • 17th & 18th century - Europeans shipped & cultivated coffee throughout colonial landholdings • Along with tea, was primary commodity of the European colonies

  7. TEA • Used in China for thousands of years before spreading throughout East • Medicinal use (3000 BC) • headaches • to keep awake during prayer • 1st brought to England by Dutch East India Company in 1657 • Spread throughout Europe by 1700

  8. Tea & East India Company • In 1773, East India Tea Company was granted permission by English Government to sell tea to American Colonies tax free • Gave them a way to bypass American merchants • So when first tea shipment arrived… • Dressed up as Indians & dumped tea in sea • Boston Tea Party • One of precipitating events in American Revolution & also reason U.S. primarily coffee drinking nation - became politically incorrect to drink tea

  9. Today • All forms of caffeine legal and fully integrated into most all societies • Most widely used psychotropic drug • HUGE industry • No illegal market

  10. Sources of Methylxanthines • Naturally Occurring Sources • Coffee • Tea • Chocolate • Kola Nut • Synthetic Sources • Cola • Pharmaceutical Preparations (alone and in combo)

  11. Sources of Methylxanthines • Chocolate - Little caffeine (less than 20 mg) • Little effect in producing arousal • Theobromine not very effective • Coffee (5 oz cup) 80-150 mg caffeine • Freeze dried - less • Drip - more • Decaffeinated - pretty much cleared out • Tea • Has half caffeine of coffee plus theophylline • Theophylline more potent than caffeine • Produces some of actions of tea not found in coffee

  12. Sources Methylxanthines • Soda – Originally from Kola Nut • Limited by law to 50 mg caffeine • Drugs • No Doz 100 mg • Vivarin 200 • Anacin 32 • Excedrin 65 • Caffeine & aspirin together make absorption much better • increases effectiveness • caffeine changes blood flow - helps headaches

  13. Route of Administration • Oral administration • Beverages: Coffee, tea, cocoa, chocolate milk, cola (fortified) • Chocolate • OTC preparations • Stimulants • Pain-killers (caffeine synergizes acetylsalicylic acid) • Diuretics and cold preparations

  14. Mechanisms of Action • Some blockade of GABA receptors • Effects are mediated by the blockade of ADENOSINE receptor • Adenosine is a neuromodulator. • Adenosine receptors coupled to other NT receptors to modulate effects of that NT. • Adenosine is an inhibitory NM. • Adenosine acts to modulate NE, DA, ACh, glutamate, and GABA. • Also leads to increased calcium in axon terminal

  15. CNS Effects • Normal doses (100-200 mg): • Alertness, sustained attention, faster thought • Reduced fatigue, lower need for sleep • Fine motor coordination, timing accuracy, and arithmetic may be impaired • Heavy dosing (1.5 grams a day) may produce agitation, anxiety, tremors, panting, and insomnia

  16. PNS Effects • Coronary artery vasodilator & bronchodilation (smooth muscle relaxer) • Increase HR (striated muscle constrictor) • Constricts cerebral arteries • Acts as diuretic (Gotta go pee)

  17. Side Effects of Caffeine • Indigestion, palpitations, tremor, insomnia, headache • Conflicting data on reproductive effects • May slow growth in utero, especially high dose • Caffeine may be harmful prior to conception • May increase the risk of spontaneous abortion • > 4 cups/day • Osteoporosis • Cholesterol increases

  18. Interactions • People smoke fewer cigarettes after drinking coffee • Smokers metabolize caffeine quicker • Caffeine only makes drunk people more awake IT DOES NOT INCREASE TIME TO SOBRIETY

  19. Toxicity • Caffeinism - 10 cups or more per day • Initial signs: insomnia, restlessness • muscle tension & shaking, tachycardia • sensory disturbances may also occur (ears ringing, light flashes) • Mild delirium & anxiety attacks may occur in predisposed individuals • Cardiac arrhythmias at 10 - 20 grams • Lethal Dose around 10 grams

  20. Tolerance • Probably does develop • Dispositional Tolerance?

  21. Dependence • Caffeine is dependence producing (2 weeks at 600mg/day) • Withdrawal effects due to increased adenosine receptor density and thus increased adenosine sensitivity • Withdrawal – Not fatal • Depression • Fatigue • Irritability • Muscle aches • Headaches