Caffeine Flashcards
Caffeine is the ______ widely used psychoactive drug worldwide.
most
What properties does it have?
It is a hydrophobic molecule, hence it has the ability to cross the BBB. It is also a psychotropic drug that can affect neurophysiology.
What effects does caffeine have on the nervous system?
Decreases fatigue, increases mental alertness/concentration, and improves performance on motor and memory tasks.
What other effects can caffeine possibly have?
- increase heart rate and blood pressure
- mild diuretic
- vaso constricts cerebral blood vessels and can provide headache relief
- it can stimulate acid release, and cause hunger, especially if consumed on an empty stomach
How does caffeine act on the body?
In the body, ATP converts food into energy. If ATP is depleted in response to cellular energy demands, ADP is produced. When the cell is low on energy, too much ADP is made, and you start to feel tired. Caffeine is an Adenosine antagonist and it blocks ADP from binding and forming. This allows the body replenish its energy stores.
Toxicity from caffeine occurs when THESE symptoms occur…….
Heart: Rapid heart rate Gastric: Nausea Muscular: Trembling Respiratory: Rapid breathing CNS: irritability, anxiety, insomnia
Caffeine causes these unpleasant side effects with these three mechanisms
- Phosphodiesterase inhibition
- GABA antagonism
- Ca2+ release
What occurs when Phosphodiesterase is inhibited?
Phosphodiesterase is an enzyme necessary to inhibit the SNS. By inhibiting Phosphodiesterase, it causes the body to be hyper-aroused.
What occurs when GABA is inhibited?
GABA is a neuron that limits nerve transmission. It provides relaxation and sedation when stimulated. Inhibition of GABA causes hyper-excitability. (increased heart rate, rapid breathing, irritability).
What occurs when Ca2+ are released?
Release of calcium ions cause muscle contractions. Caffeine causes an influx of calcium to be releases by binding to muscle fibres. This can increase heart beat, cause muscle twitching, and irregular heart rhythms.
How is the effect of caffeine different for some people?
- genetics
- taking on an empty stomach
- amount in plasma concentration
- CYP enzyme (induce or inhibit)
- sensitivity to caffeine
What is the absorption process for caffeine?
- taken orally
- reaches peak concentration within 15 mins to two hours
What is the distribution process?
-hydrophobic, can readily distribute to BBB
What is the metabolism process?
- stays for 3-7 hours
- may be different for pregnant woman
Is caffeine used in other drugs?
yes as an analgesic for headache relief and for respiratory issues
Is caffeine addictive?
It can have some form of dependence but is not enough to threaten well being.
Can withdrawal occur?
Yes, it can occur in as little as 1-2 days but is alleviated within 3 days with caffeine intake.
What are the withdrawal symptoms?
- fatigue
- irritability
- headache
Is caffeine bad?
No, it does pose a life threatening risk.
What is meta-analysis?
Combines many, similar, smaller studies to find a “common truth.”
What are the advantages of meta-analysis?
increased precision with more data to a generalized population
What are the disadvantages of meta-analysis?
- several, small studies are not as good as one large study
- no compensation for poor study design
- conclusions are subject to publication bias and “cherry picking.”
How come studies on caffeine cannot be proven for sure?
most studies look into coffee rather than caffeine. Other extraneous factors are not monitored. (i.e. milk, sugar, how much is actually consumed)
loop holes: prevents diabetes –> maybe person doesn’t like sugar, hence they don’t consume it regardless of coffee consumption
- reduces cardiovascular risk –> person may just walk to coffee shop
