CAFFEINE

Question 1

caffeine

Answer 1

• most widely consumed psycho-trophic drug in world
• psychoactive drug
• methylxanthine family (theophylline & theobromine too)

Question 2

caffeine history

Answer 2

• origin not well understood
• naturally occuring
• isolated from coffee 1820
• mild stimulant

Question 3

caffeine sources

Answer 3

• coffee beans
• cocao pod
• kola nuts
• tea
• headache pills
• stay awake pills
• varying levels

Question 4

ubiquitous use signficance

Answer 4

• cradle to grave → non-medical use at all ages
• highest consumption in Scandinavia
• highest dose/weight consumed by children
• 2nd highest dose/weight in 18 yrs and older

Question 5

caffeine therapeutic uses

Answer 5

• headache medication → relieves headache, caffeine withdrawal, helps painkillers work better
• stimulate breathing → treatment of apnea in newborn babies

Question 6

caffeine PK

Answer 6

• rapidly absorbed from gut
• crosses BBB & peaks 15-45mins
• metabolized via liver
• excreted in urine
• half-life 3-7hrs so stays in system for awhile
• metabolism influenced by liver disease, pregnancy, contraceptive

Question 7

factors influencing metabolism

Answer 7

• liver disease ↓
• pregnancy ↓
• contraceptive use dependent on BC ↓ or ↑
• smoking ↑
• age ↓

Question 8

caffeine mechanism of action

Answer 8

• competitive antagonist at adenosine receptors
• binds to active site, preventing ligand (adenosine) from binding
• compete for same spot
• inhibitory → prevents effects of adenosine
• increases ACh, DA, NE, 5-HT
• decreases GABA (main inhibitory)

Question 9

adenosine receptors

Answer 9

• G-coupled protein
• CNS & PNS
• activation = sedation, oxygen regulation, dilation of coronary/cerebral vessels
• caffeine prevents activation
• blocked receptors → stimulant-like effects
• decreases ACh, DA, NE, 5-HT
• increase GABA (main inhibitory)

Question 10

small dose PNS effects

Answer 10

• increases: metabolism, breathing, urination, BP, vasodilation, sympathomimetic

Question 11

small dose CNS effects

Answer 11

• elevates activity
• postpones fatigue
• enhances simple task performance
• delays sleep onset, shortens sleep

Question 12

large dose effects

Answer 12

• produces headaches
• jitteriness
• rapid HR
• caffeinism
• overdoses rare but often from too many caffeine pills
• 10g adults, 100mg children

Question 13

caffeinism

Answer 13

• typically experienced after 1000mg
• resembles state of diabetic without insulin
• light-headedness, tremors, breathlesness, irregular heartbeat, high blood sugar

Question 14

caffine toxic effects

Answer 14

• don’t appear under 500mg/day
• > 500mg/day start to see effects
• chronic insomnia
• persistent anxiety & depression
• stomach ulcers
• raises cholesterol (depends on how prepared)

Question 15

caffeine withdrawal

Answer 15

• rapid tolerance to stimulating effects
• headaches, irritability, nausea, fatigue, sedation
• associated >350mg/daily
• appears with abrupt cessation of as little as 1-2cups/day
• effects within 12-24hrs
• lasts up to a week post last caffeine intake

Question 16

methylxanthines medical benefits

Answer 16

• cerebral stimulation → caffeine
• coronary dilation → theophylline (tea)
• diuresis → theobromine (cocoa)
• respiratory stimulant → caffeine

Question 17

energy drinks

Answer 17

• VERY high caffeine levels
• consumed rather quickly
• not FDA regulated
• marketed to adolescents
• common to mix with alcohol → try to counteract motor impairment/sedative effects of alc
• with alc, reduced perception of headaches, weakness, & motor impairment but no real change

Question 18

mouse study

Answer 18

• adolescent exposure to alcohol & caffeine → cross-tolerance with cocaine
• increased natural reward consumption (i.e.)
• increased markers of neuronal activity in NAC