Transcript Caffeine
Nikki, Bryan, Kyla Caffeine • Caffeine is one of the most widely used drugs in the world. • It is estimated that ______% of adults in the United States regularly drink caffeinated beverages. • It has also been estimated that the average adult caffeine intake in the United States is 200 to 400 mg per day. • Caffeine can be found in all sorts of things like coffee, energy drinks, soft drinks, chocolate, migraine medicine, tea, dietary supplements, etc. • Caffeine is normally consumed orally through the beverages or food in which it is present. Caffeine • Caffeine is a psychoactive drug that acts as a CNS stimulant • Its chemical name is 1,3,7-trimethyl-1Hpurine-2,6(3H,7H)-dione • Its generic name is Caffeine • Some brand names are_______________ Primary Uses • Caffeine has many uses – It does not affect all people in the same way – Most people who do consume caffeine do so on regular basis • Athletes use caffeine to improve their performance and be on top of their game • _________ sufferers use caffeine to alleviate their pain • Night shift employees or truck drivers may use it to make fewer mistakes as a result of being tired or to increase alertness during sleep deprivation • Students may use caffeine to stay up late studying • It is primarily used as a mild CNS stimulant to aid in staying awake and restore mental alertness Behavioral Effects • There are numerous behavioral effects for primary use and some major side effects • Studies demonstrated _________ effects in rodents – At low doses it had stimulant effects – At high doses rodents showed reduced activity levels. • Humans do not show behavioral depression but they do experience tension and anxiety at higher doses • Caffeine does more than just increase arousal. There are a variety of positive subjective effects, such as: – Feelings of well-being, enhanced energy or vigor, increased alertness and ability to concentrate, self-confidence, increased work motivation, enhanced sociability, and reduced tension Undesirable Side Effects • There are multiple unwanted or undesirable side effects as well, such as: – increased blood pressure and respiration rate, enhanced water excretion, etc. • Caffeine has a positive ionotropic effect on the myocardium and chronotropic effect on the sinoatrial node – Results in a transient increase in heart rate, force of contraction, and cardiac output • Some additional side effects are as follows but not limited to; nervousness, insomnia, restlessness, irritability, confusion, agitation, delirium, twitching, tremors, convulsions, tingling of face, flushing, palpitation, nausea, vomiting, epigastric discomfort, gastric irritation, diarrhea, etc. Background and History of Coffee • ________________, a coffee plant with berries – Arabian tale about Kaldi and his goats – This shows early evidence that coffee provides energy • They think that coffee crossed the Red Sea early in its history, as early as A.D. 575 • It arrived in England in the early 1600s as a medicine • First English coffeehouse opened in Oxford in 1650, and others soon after in London • There was some time of political turmoil – It has been said that “England’s great struggle for political liberty was fought and won in the coffeehouse Background and History of Coffee • By 1690, coffeehouses were firmly established in English life • Helped reduce drunkenness during the gin epidemic in the early 1700s • However, coffee consumption decreased from 3.1 cups a day for adults in 1960 to only 1.75 cups per day in 1991 – People were trying to be more health conscious Mechanisms of Action • The mechanisms of action, neurotransmitter systems, and the receptor subtypes are not completely clear, but much progress has been made with time • Caffeine is rapidly absorbed – Reaches peak concentration within ______ minutes. • It is water-soluble and lipid-soluble, which allows it to cross the BBB • It has a wide distribution and an almost immediate effect on alertness • Originally it was thought that it directly influenced catecholamine systems, and that it was an inhibitor of cAMP phosphodiesterase. It was thought that it blocked GABA(A) receptors and that it stimulated CA++ release within cells Mechanisms of Action • More recent studies have led us to believe that it actually blocks A1 and _____ receptors for adenosine • Adenosine plays a role in energy via adenosine triphosphate (ATP) • Adenosine in the brain can serve a neurotransmitterlike function • Caffeine reduces the effects of adenosine by binding to adenosine receptors, but not activating them • There are four different adenosine receptor subtypes A1, A2A, A2B, and A3 Mechanisms of Action • Caffeine is thought to block A1 and A2A receptor subtypes in laboratory animals – These receptor subtypes are thought to mediate most of the behavioral effects of caffeine • A1 and A2A receptors – A1 receptors thought to inhibit calcium uptake – A2A receptors are thought to play a role in behavioral control and interact with the _____ system – _____ system is intertwined with reward and arousal • Growing evidence from animal studies demonstrate that adenosine is a sleep- or drowsiness- inducing factor released after a period of waking – Explains why caffeine use in humans causes increased alertness and suppression of sleep Absorption and Metabolism • There are several factors related to route of administration, absorption, distribution, and fate • Caffeine is rapidly absorbed. It is actually peaks 15-45 minutes after administration • It is widely distributed throughout the body, and metabolized in the liver • Metabolites account for almost all caffeine excretion – Only 1 to 2% is excreted unchanged • In humans approximately ____% of caffeine metabolites are eliminated through urine, 2-5% through feces, and the remainder through body fluids like saliva • Metabolism is influenced by prior ingestion of caffeine, gender, smoking status, and other drugs Interactions With Other Drugs • Cigarette smoke used repeatedly causes an increase in a liver enzyme known as ________________________ – This speeds up the rate of biotransformation/metabolism of caffeine – People who are heavy smokers may need higher doses of caffeine, because it is metabolized by the same enzyme • Caffeine also interacts with other drugs – It increases the effects of cimetidine and theophylline toxicity Half Life • Caffeine’s half-life is _____ hours in adults • The half life in neonates ranges from 36 to 144 hours – It is also excreted in small amounts in the breast milk • Caffeine is classified as a FDA pregnancy category B, meaning it freely crosses the placenta Caffeine Tolerance • Regular caffeine use can lead to tolerance to some of caffeine’s subjective effects as well as disrupt sleep • Chronic caffeine use can produce tolerance to the cardiovascular and respiratory effects of the drug • Some withdrawal symptoms are: – Headache, lethargy, fatigue, impaired concentration, impaired psychomotor performance, and in some cases mild anxiety or depression Physiological Effects • Heavy coffee drinking has been linked with increased blood pressure and a heightened risk of coronary heart disease • High caffeine consumption has also been reported to be associated with low infant birth weight Other Effects • Chronic ingestion of excessive amounts of caffeine can lead to a syndrome called ____________. • Caffeinism is characterized by restlessness, nervousness, insomnia, and physiological disturbances, such as tachycardia and gastrointestinal upset. • Extremely high doses of caffeine may produce even more severe psychiatric effects. • Caffeine consumption causes physical dependence and can also lead to a compulsive use pattern. • Caffeine is reinforcing to regular users. Caffeine reinforcement is related to a combination of functional enhancement and relief from withdrawal symptoms. Addiction??? • Components Model of Addiction (Griffiths) – Excessive? – Mood Modification? – Salience? – Tolerance? – Withdrawal? – Conflict? – Relapse? References • Berardi, R.R. (2009). Handbook of nonprescription drugs an interactive approach to self-care (16th ed.). Ann Arbor, MI :American Pharmacists Association • Hardman, J. G., Limbird, L.E. (Eds). (2001). The pharmacological basis of therapeutics • (10th ed.). New York, NY: McGraw Hill Medical Publishing Division. • Meyer, J.S., Quenzer, L.F (2005). Psychopharmacology drugs, the brain, and behavior. Sunderland, MA: Sinauer Associates, Inc. • Murray, L. (Ed.). (2008).PDR for nonprescription drugs, dietary supplements, and herbs • (29th ed.). Montvale, NJ: Thomson Healthcare Inc. • Shannon, M.T., Stang, C.L., Wilson, B. A. (1995). Drugs and nursing implications (8th ed.). Norwalk, CT: Appleton and Lange. • Shannon, M.T., Stang, C.L., Wilson, B. A. (1998). Nurses drug guide. Stanford, CT: • Appleton and Lange • Reserved Reading #5 from Moodle Questions???