CNS stimulants Flashcards
Caffeine is a _______, which is structurally similar to purines.
methylxanthine
What are two methylxanthine related molecules found in tea?
theophylline
theobromine
What is the mechanism of caffeine?
at normal dose
competitive agonist of adenosine receptors
=> postsynaptic receptors produce IPSP
=> presynaptic receptors inhibit glutamate
*dis-inhibition leading to CNS stimulation
What is the mechanism of caffeine at higher doses?
inhibit cAMP phosphodiesterase
=> increase in cAMP
beneficial effects in asthma
also induces release of Ca++ from intracellular ER
=>stimulate medullary respiratory and CV centers (tachycardia)
Cocaine is active in the _____ form, predominant in ____ pH.
unionized/unprotonated form (B)
predominates in high pH
Cocaine has a _____ half-life of about ___ minutes.
Short half-life about 50 minutes.
in CNS even shorter about 10-30 minutes.
What is the mechanism of cocaine?
inhibitor of reuptake of NE, dopamine, serotonin
Reinforcing effects of cocaine are due to ____ in the synapse.
Dopamine
Increase in NE due to cocaine can cause what peripherally and centrally?
peripheral sympathomimetic - vasoconstrict, tachycardic
centrally cause alertness, vigilance
Fetal effects of cocaine? (3)
low birth weight
learning and emotional problems
attachment disorder
Cocaine is often used as local anesthetic in the _______.
upper respiratory tract (surgery of the nose)
anesthetic & vasoconstrict!
Amphetamine and methamphetamine are structurally similar to _____.
norepinephrine
Unlike cocaine, amphetamine and methamphetamine are well absorbed ______ and has _____ half-life.
orally, longer
What are the mechanisms of action for amphetamine and methamphetamine? (4)
-release NE, DA, 5HT from neurons
-block reuptake
-partial agonist of alpha receptors
-MAO inhibitor at high doses
(more NE-life effect than cocaine)
What are some clinical uses for amphetamine and methylphenidate? (2)
- narcolepsy
- ADHD
What are the side effects of amphetamine and methylphenidate (6)
- insomnia
- abdominal pain
- anorexia, weight loss
- suppression of growth
- fever
- facial ticks
What are the toxicities of amphetamine and methylphenidate? (5)
sympathomimetic psychosis neurotoxic meth mouth abuse
Why is methamphetamine more liable to abuse?
gets into brain better!
Nicotine affects autonomic ganglia and causes (sympathetic & parasympathetic)
- sympathetic: release of epinephrine from adrenal
- parasympathetic: GI effects (nausea, increased motility)
Nicotine produces neuronal excitation through _____ ______.
membrane depolarization
Nicotine activates dopamine signaling in _____ ______ in the CNS; making it reinforcing.
nucleus accumbens
What “zone” does nicotine activate and cause nausea?
chemoreceptor trigger zone
Describe in ONE word why the first cigarette of the day is the best.
tachyphylaxis
Nicotine withdrawal symptoms include (5)
- irritability, hostility, impatience
- anxiety
- depression
- difficulty concentrating
- increased appetite, weight gain
Name two pharmacotherapies for nicotine dependence
bupropion, varenicline
How does bupropion work?
reduces craving and lessen withdrawal symptoms
-antidepressant
How does varenicline work?
partial agonist of nicotinic receptors
-blocks effects of nicotine (since it’s partial)
What is the major concern with varenicline?
increased suicidal thoughts and depression!
