Caffeine (redirected from Theine)

caffeine (kăfēn`), odorless, slightly bitter alkaloid found in coffee, tea, kola nuts (see cola), ilex plants (the source of the Latin American drink maté), and, in small amounts, in cocoa (see cacao). It can also be prepared synthetically from uric acid. While relatively harmless, it is the most commonly used mind-altering drug in the world. When used in moderation, caffeine acts as a mild stimulant to the nervous system, blocking the neurotransmitter adenosine and resulting in a feeling of well-being and alertness. It increases the heart rate, blood pressure, and urination and stimulates secretion of stomach acids; excessive intake can result in restlessness, insomnia, and heart irregularities. The effects of caffeine vary from person to person, as people excrete it at different rates. Physical dependence and unpleasant symptoms upon withdrawal (headache, fatigue, depression) are common in regular caffeine users.

Bibliography

See B. A Weinberg and B. K. Bealer, The World of Caffeine (2001).

---

caffeine

Heterocyclic compound that, like other alkaloids, has marked physiological effects. It occurs in coffee beans, tea leaves, kola nuts, cacao, maté, and guarana and in the products made from them. Its stimulating effect on the central nervous system, heart, cardiovascular system, and kidneys makes it medically useful in treating respiratory depression caused by overdose of barbiturates, morphine, or heroin. Its positive effects can include improved motor performance, decreased fatigue, increased alertness, and enhanced sensory activity. Excessive caffeine can produce irritability, anxiety, insomnia, and potentially serious symptoms such as heart irregularities and delirium. Much of the caffeine included in many over-the-counter stimulants, cold remedies, and painkillers has been extracted during production of decaffeinated coffee and tea.

---

caffeine, caffein

a white crystalline bitter alkaloid responsible for the stimulant action of tea, coffee, and cocoa: a constituent of many tonics and analgesics. Formula: C₈H₁₀N₄O₂

---

caffeine [′kaf‚ēn]

(organic chemistry)

C₈H₁₀O₂N₄·H₂O An alkaloid found in a large number of plants, such as tea, coffee, cola, and mate.

---

Caffeine 

a central nervous system stimulant; trimethylxanthine, an alkaloid found in tea leaves, coffee beans, and kola nuts and obtainable synthetically.

Caffeine is administered in tablet form in cases of central nervous system depression, weak cardiac activity, narcotic intoxication, hypotonia, and migraine. A solution of caffeine and sodium benzoate, containing 38 percent pure caffeine and administered subcutaneously, has similar pharmacological properties and indications.