Nikki, Bryan, Kyla

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Nov 12, 2013 (3 years and 4 months ago)

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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
-
1H
-
purine
-
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 neurotransmitter
-
like 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 (
16
th

ed
.).

Ann Arbor, MI :American Pharmacists
Association


Hardman, J. G., Limbird, L.E. (Eds). (2001).
The pharmacological basis of
therapeutics



(10
th

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


(
29
th

ed
.)
. Montvale, NJ: Thomson Healthcare Inc.


Shannon, M.T., Stang, C.L., Wilson, B. A. (1995).
Drugs and nursing
implications (
8
th

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???