stimulants, anorexigenics and hallucinogens Flashcards
What is the mechanism of action of cocaine?
inhibits reuptake by presynaptic neuron of dopamine, serotonin and norepinephrine by blocking the transporter (DAT, SERT, NET) on the presynaptic membrane
What are the amphetamine-like drugs? What is their mechanism of action?
amphetamine, methamphetamine, methylphenidate (ritalin), phentermine
1) They are competing substrates for the reuptake transporter of dopamine (DAT) thereby inhibiting the reuptake by the presynaptic neuron.
2) compete with dopamine for the vesicular monoamine transporter (VMAT) that loads dopamine into vesicles. Less dopamine gets loaded into vesicles and more dopamine is released non-vesicularly into the synapse
what is the mechanism of action of caffeine?
is a competitive antagonist of adenosine receptors
increasing adenosine levels promote sleep
what is the mechanism of nicotine?
agonist of central nicotinic acetylcholine receptors
What are the signs of stimulant withdrawal?
“crash” period with intense drug craving, depression, anxiety and agitation
Intermediate phase - fatigue, loss of mental energy, decreased interest in environment
What are the effects of cocaine outside the CNS? What are the effects of amphetamines outside the CNS?
cocaine - increased cardiac contractility, heart rate and blood pressure (can cause stroke with chronic use); coronary vasoconstriction (increases norepi in the synapse of alpha receptors in blood vessels). High risk of arrhythmias and heart attacks
amphetamines - increased blood pressure with possible bradycardia. High risk of arrhythmias
How is cocaine eliminated? How are amphetamines eliminated?
cocaine - metabolized by esterases in the plasma and liver to benzoylecgonine and excreted by the kidney
amphetamines - not metabolized. Excreted unchanged by the kidney
What combination of drugs are FDA approved for weight loss?
phentermine and topiramate
What is the treatment for ADHD?
amphetamine, methamphetamine or methylphenidate
What are the indications for modafinil?
a stimulant for excessive sleepiness due to narcolepsy, obstructive sleep apnea and shift work sleep disorder
off label treatment for ADHD
What are the indications for caffeine?
episodes of apnea and bradycardia in premature infants
lumbar puncture headaches
augmentation of seizure induction for electroconvulsive therapy for depression
What are the CNS effects of nicotine? Peripheral effects?
CNS effects - arousal, relaxation, enhances mood, attention and reaction time.
Peripheral effects - low doses: increased HR, BP, CO and vasoconstriction. high doses: releases adrenal catecholamines
What are the synthetic cathinones? What is the mechanism of action of the synthetic cathinones?
mephedrone, methylone
stimulates monoamine neurotransmitter release and inhibiting its reuptake from the synaptic cleft
What are the CNS effects of synthetic cathinones? Peripheral effects?
CNS: paranoia, auditory and tactile hallucinations, psychosis, myoclonus
Peripheral: hyperthermia, hyponatremia, tachycardia, rhabdomyolysis and compartment syndrome
Which amphetamine has the longest half life?
phentermine, the long half life lowers its potential for abuse
What are the indications for amphetamine?
ADHD, narcolepsy
What are the indications for methamphetamine?
ADHD, narcolepsy, exogenous obesity
What are the indications for methylphenidate?
ADHA, narcolepsy, depression in medically ill older adults
What are the indications for phentermine?
exogenous obesity
What are the major groups of hallucinogens? What important drugs fall into these major groups?
5HT2A partial agonists - LSD, MDMA, mescaline in peyote, psilocybin in mushrooms
Glutamate antagonists - PCP
muscarinic antagonists - no important drugs
What are the peripheral effects of hallucinogens?
mydriasis, increased BP and HR
How are LSD and MDMA eliminated? How long are their half-lives/
by the liver.
half life of LSD = 4 hours, MDMA = 7 hours
Which drugs are abused but not addictive/won’t produce withdrawal symptoms?
the 5HT2A partial agonists, LSD and MDMA
What are the symptoms of LSD and MDMA use?
visual hallucinations, synesthesias (crossing of sensory modalities like smelling colors), dilation of time, feelings of oneness with the universe
What are the symptoms of PCP use? At high toxic doses?
hostile or combative behavior visual and auditory hallucinations numbness and insensitivity to pain Increased HR, BP and sweating At high toxic doses: general anesthesia, coma with paralytic mydriasis, catatonia
What type of drug is dronabinol? What are its indications?
Dronabinol is an synthetic cannabinoid that is used for anorexia in patients with AIDS, last resort antiemetic for cancer patients, prophylaxis and treatment of post-surgical nausea
What are the proposed medical uses of medical marijuana?
nausea
apetite stimulation
reduction of intraocular pressure (nonsense according to Blitzer)
reduction of spasticity of patients with multiple sclerosis
What drug is a cannabinoid receptor antagonist? What are its indications?
rimonabant is a CB1 receptor antagonist that is used to treat obesity and help patients lose weight
