Caffeine Chapter 8

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

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

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

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

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

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

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

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

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

Sources of Methylxanthines Chocolate - Little caffeine (less than 20 mg) Little effect in producing arousal Theobromine not very effective Coffee (5 oz cup) 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

Sources Methylxanthines Soda – Originally from Kola Nut Limited by law to 50 mg caffeine Drugs No Doz100 mg Vivarin200 Anacin 32 Excedrin 65 Caffeine & aspirin together make absorption much better increases effectiveness caffeine changes blood flow - helps headaches

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

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

CNS Effects Normal doses ( 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

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

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

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

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 grams Lethal Dose around 10 grams

Tolerance Probably does develop Dispositional Tolerance?

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