Lecture 44: Stimulants Flashcards
On and off label indications for stimulants (6)
Exogenous obesity, ADHD, narcolepsy, fatigue, cessation of tobacco use, local anesthesia
Broadly, cocaine and amphetamine do what?
Increase synaptic levels of DA, NE, and 5HT
What is the mechanism of cocaine?
Inhibits DA reuptake
What is the dual effect of amphetamines? How does this increase DA in the synapse?
Compete w/ DA for reuptake and for vesicular packaging; leads to nonvesicular release of DA
What is the only FDA-approved use of cocaine?
Topical anesthetic
What are the peripheral effects of cocaine and the underlying mechanism
Potent vasoconstrictor because it increases NE at sympathetic synapses
Cocaine is eliminated where? (2) One important metabolite is useful for what function?
Plasma and hepatic esterases; metabolite can be detected in urine for up to a week after binge use
Name the four key amphetamines in order of increasing half-lives. Where are they eliminated?
Methylphenidate, amphetamine, methamphetamine, phentermine; kidney
Broadly, amphetamines are prescribe for two things…
ADHD and narcolepsy
Which two amphetamine can also be prescribed for exogenous obesity?
Methamphetamine and phentermine
Off-label, methylphenidate has been used…
To treat depression in medically ill older adults
The D amphetamine isomer is active where? What about L? Relevance for methamphetamine? How about amphetamine?
D = CNS, L = ANS; D-meth = prescribed form, L-meth = decongestant; amph = mix (75% D)
What are the cardio effects of amphetamines as they compare to cocaine?
Increase BP but variable effect on HR (can even see reflex bradycardia)
Describe two phases of amphetamine withdrawal
“Crash” (anxiety, craving) then withdrawal (fatigue)
Modafinil is prescribed for (3)…off label (2)…
Narcolepsy, shift disorder, sleep apnea; ADHD, fatigue in MS
How is Modafinil similar and different compared to the amphetamines?
Stimulant, but structurally unrelated (mechanism not well understood), low risk of addiction
Caffeine is a what at what receptor?
Adenosine receptor antagonist
Nicotine is a what at what receptor?
Full agnoist at nAChRs
CNS effects
Arousal, relaxation, enhanced mood, attention
PNS effects
Increase BP, HR, CO, vasoconstriction
At very high doses, what does nicotine cause?
Hypotension and bradycardia
What are synthetic cathinones derived from? Where are they found (on the streets) and what is their mechanism similar to?
Khat; bath salts; amphetamines
Hallucinogens do what at what receptor? (2 categories, name relevant drugs)
LSD, MDMA: partial agonist at 5HT2A receptor; PCP: NMDA glutamate receptor antagonist
Are there tolerance or withdrawal symptoms for LSD/MDMA?
Tolerance, yes; withdrawal, no
