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29 Cards in this Set
- Front
- Back
- 3rd side (hint)
What is the definition of a CNS stimulant
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A CNS stimulant is a drug that increases motor activity, causes excitement, and decreases feelings of fatigue. CNS stimulants include the methylxanthines, nicotine, and the amphetamines
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What are methylxanthines
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A group of psychomotor stimulants including:
Caffeine Theophylline Theobromine (found in cocoa but of little interest) |
None
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How do methylxanthines work
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Research indicates that methylxanthines increase cGMP and cAMP by inhibiting phosphodiesterase and blocking adenosine receptors
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What are the physiologic effects of caffeine
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Caffeine affects a number of organ systems within the body:
CNS—Caffeine increases motor activity and alertness Cardiovascular—Caffeine increases heart rate and contractility Smooth muscle—Caffeine and its derivatives relax the smooth muscles of the bronchioles Genitourinary—Caffeine can act as weak diuretic and increase urinary output of Na+, Cl-, and K+ Gastrointestinal—Caffeine stimulates secretion from the gastric mucosa. Therefore, patients who have peptic ulcer disease should be counseled to avoid caffeine |
None
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What are the adverse effects of chronic caffeine use
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At low dose—Insomnia and agitation can occur
At higher doses (8-10g)—Emesis, convulsions, and even cardiac arrhythmias can occur |
None
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Do methylxanthines cross the placenta
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Yes, and they are secreted into the mother’s milk. Patients should be advised to avoid them during pregnancy and while nursing
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What is the therapeutic role of theophylline
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Theophylline can be used in the treatment of asthma, but currently it is not being used frequently because it has a very narrow therapeutic index and is not as effective as the new β agonists
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How are the physiological effects of nicotine related to the dose
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In low doses, nicotine causes ganglionic stimulation by depolarization. At high doses is causes ganglionic blockade
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What are the physiologic actions of nicotine on the CNS
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At low doses—arousal, relaxation, and improved attention
At high doses—central respiratory paralysis caused by disruption of medullary function |
None
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How does nicotine affect the peripheral nervous system
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At low doses—increase in blood pressure and heart rate; constriction of blood vessels to the digits and impairment of flow
At high doses—decrease in blood pressure and in action of GI and GU tract due to ganglionic blockade |
None
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What are nicotine’s therapeutic uses
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Nicotine has no therapeutic uses
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What is nicotine’s rout of administration
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Absorption occurs through oral mucosa, by inhalation, and transdermally
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What are nicotine’s adverse effects
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CNS—irritability and tremors
Peripheral—intestinal cramps, diarrhea, and increased heart rate and blood pressure |
None
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What withdrawal symptoms do nicotine addicts experience
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A craving for tobacco is accompanied by irritability, restlessness, anxiety, and gastrointestinal pain
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Name three examples of amphetamines
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Methylphenidate (Ritalin)
Methamphetamine (Methedrine)—“speed” Dextroamphetamine (Dexedrine) |
None
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How do amphetamines work
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Amphetamines work by releasing neuronal stores of catecholamines, especially norepinephrine and dopamine
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What are the physiologic actions of amphetamines
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Euphoria
Decrease in fatigue Increase in blood pressure Increase in rate of respiration Decrease in appetite |
None
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What is the clinical use of amphetamines
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ADHD—Methylphenidate is used to alleviate this problem
Appetite control—Amphetamines decrease appetite by blocking the receptors in the lateral hypothalamus Narcolepsy |
None
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What is the route of administration for amphetamines
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Oral
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Where are amphetamines metabolized
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In the liver
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Does physiologic and psychological dependence occur with amphetamine use
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Yes—amphetamines can be very addictive
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What are the adverse effects of amphetamines
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Amphetamines, like caffeine and nicotine, affect multiple organ systems:
CNS—insomnia, irritability, convulsions; chronic use can lead to a psychotic state resembling schizophrenia Gastrointestinal—anorexia, nausea, dry mouth Cardiovascular—palpitations, angina, arrhythmias, hypertension |
None
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Amphetamines are contra-indicated with what group of drugs
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The MOA inhibitors
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How is amphetamine overdose managed
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Chlorpromazine is beneficial in amphetamine overdose because it blocks the α receptors which are responsible for the CNS disturbances and hypertension
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What is the mechanism of action of amphetamines
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Increases the release of catecholamines from presynaptic nerve endings
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What is cocaine’s mechanism of action
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Cocaine blocks the reuptake of norepinephrine, serotonin, and dopamine into presynaptic nerve terminals. This blockade results in enhanced activity of these neurotransmitters
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What physiologic changes occur as a result of cocaine use
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Cocaine causes mydriasis, increases heart rate, alertness, and self confidence, and induces a temporary state of euphoria by stimulating the limbic system
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What are the signs of cocaine overdose
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Excitation
Hallucinations and psychosis Seizures Respiratory depression Arrhythmias secondary to coronary vasospasm Coma |
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Does cocaine have any clinical use
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Yes—it is used as a local anesthetic and vasoconstrictor during ENT procedures
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