Transcript Caffeine

Nikki, Bryan, Kyla
• 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 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,
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
• 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
– It is also excreted in small amounts in the breast
• Caffeine is classified as a FDA pregnancy
category B, meaning it freely crosses the
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
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.
• Components Model of Addiction (Griffiths)
– Excessive?
– Mood Modification?
– Salience?
– Tolerance?
– Withdrawal?
– Conflict?
– Relapse?
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• Reserved Reading #5 from Moodle