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Caffeine Chapter 8. Caffeine Most used drug in the world An alkaloid belonging to a class of...

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Caffeine Chapter 8
Transcript

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 - 1650 1700s London - 2000 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) 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

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

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 (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

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 awakeIT 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 10 - 20 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


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