3Caffeine 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.
4Caffeine Caffeine is a psychoactive drug that acts as a CNS stimulant Its chemical name is 1,3,7-trimethyl-1H-purine-2,6(3H,7H)-dioneIts generic name is CaffeineSome brand names are_______________
5Primary Uses Caffeine has many uses It does not affect all people in the same wayMost people who do consume caffeine do so on regular basisAthletes use caffeine to improve their performance and be on top of their game_________ sufferers use caffeine to alleviate their painNight shift employees or truck drivers may use it to make fewer mistakes as a result of being tired or to increase alertness during sleep deprivationStudents may use caffeine to stay up late studyingIt is primarily used as a mild CNS stimulant to aid in staying awake and restore mental alertness
6Behavioral EffectsThere are numerous behavioral effects for primary use and some major side effectsStudies demonstrated _________ effects in rodentsAt low doses it had stimulant effectsAt high doses rodents showed reduced activity levels.Humans do not show behavioral depression but they do experience tension and anxiety at higher dosesCaffeine 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
7Undesirable 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 nodeResults in a transient increase in heart rate, force of contraction, and cardiac outputSome 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.
8Background and History of Coffee ________________, a coffee plant with berriesArabian tale about Kaldi and his goatsThis shows early evidence that coffee provides energyThey think that coffee crossed the Red Sea early in its history, as early as A.D. 575It arrived in England in the early 1600s as a medicineFirst English coffeehouse opened in Oxford in 1650, and others soon after in LondonThere was some time of political turmoilIt has been said that “England’s great struggle for political liberty was fought and won in the coffeehouse*Kaldi saw his goats acting exuberantly on a hillside, and traced the cause to some berries where the goats were grazing. Kaldi tried the berries and soon he had joined the goats. He took the berries to a holy man, who said the drug would aid in prolonging the stamina of dervishes (a Muslim member, some of which carry on ecstatic observances, such as energetic dancing and whirling or vociferous chanting or shouting.)
9Background and History of Coffee By 1690, coffeehouses were firmly established in English lifeHelped reduce drunkenness during the gin epidemic in the early 1700sHowever, coffee consumption decreased from 3.1 cups a day for adults in 1960 to only 1.75 cups per day in 1991People were trying to be more health conscious*But coffee consumption has increased again due to gourmet coffee, and the fact that it is affordable and a socially acceptable drug.*If you would like to know how to make The Perfect Cup of Coffee, you can read the reserved reading #5 on Moodle ;)
10Mechanisms of ActionThe mechanisms of action, neurotransmitter systems, and the receptor subtypes are not completely clear, but much progress has been made with timeCaffeine is rapidly absorbedReaches peak concentration within ______ minutes.It is water-soluble and lipid-soluble, which allows it to cross the BBBIt has a wide distribution and an almost immediate effect on alertnessOriginally 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
11Mechanisms of ActionMore recent studies have led us to believe that it actually blocks A1 and _____ receptors for adenosineAdenosine plays a role in energy via adenosine triphosphate (ATP)Adenosine in the brain can serve a neurotransmitter-like functionCaffeine reduces the effects of adenosine by binding to adenosine receptors, but not activating themThere are four different adenosine receptor subtypes A1, A2A, A2B, and A3
12Mechanisms of ActionCaffeine is thought to block A1 and A2A receptor subtypes in laboratory animalsThese receptor subtypes are thought to mediate most of the behavioral effects of caffeineA1 and A2A receptorsA1 receptors thought to inhibit calcium uptakeA2A receptors are thought to play a role in behavioral control and interact with the _____ system_____ system is intertwined with reward and arousalGrowing evidence from animal studies demonstrate that adenosine is a sleep- or drowsiness- inducing factor released after a period of wakingExplains why caffeine use in humans causes increased alertness and suppression of sleep
13Absorption and Metabolism There are several factors related to route of administration, absorption, distribution, and fateCaffeine is rapidly absorbed. It is actually peaks minutes after administrationIt is widely distributed throughout the body, and metabolized in the liverMetabolites account for almost all caffeine excretionOnly 1 to 2% is excreted unchangedIn humans approximately ____% of caffeine metabolites are eliminated through urine, 2-5% through feces, and the remainder through body fluids like salivaMetabolism is influenced by prior ingestion of caffeine, gender, smoking status, and other drugs
14Interactions 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 caffeinePeople who are heavy smokers may need higher doses of caffeine, because it is metabolized by the same enzymeCaffeine also interacts with other drugsIt increases the effects of cimetidine and theophylline toxicity
15Half Life Caffeine’s half-life is _____ hours in adults The half life in neonates ranges from 36 to 144 hoursIt is also excreted in small amounts in the breast milkCaffeine is classified as a FDA pregnancy category B, meaning it freely crosses the placenta
16Caffeine ToleranceRegular caffeine use can lead to tolerance to some of caffeine’s subjective effects as well as disrupt sleepChronic caffeine use can produce tolerance to the cardiovascular and respiratory effects of the drugSome withdrawal symptoms are:Headache, lethargy, fatigue, impaired concentration, impaired psychomotor performance, and in some cases mild anxiety or depression
17Physiological Effects Heavy coffee drinking has been linked with increased blood pressure and a heightened risk of coronary heart diseaseHigh caffeine consumption has also been reported to be associated with low infant birth weight
18Other EffectsChronic 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.
19Addiction??? Components Model of Addiction (Griffiths) Excessive? Mood Modification?Salience?Tolerance?Withdrawal?Conflict?Relapse?
22ReferencesBerardi, R.R. (2009). Handbook of nonprescription drugs an interactive approach to self-care (16th ed.). Ann Arbor, MI :American Pharmacists AssociationHardman, 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 LangeReserved Reading #5 from Moodle