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29 Cards in this Set

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What is the definition of a CNS stimulant
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
What are methylxanthines
A group of psychomotor stimulants including:
Caffeine
Theophylline
Theobromine (found in cocoa but of little interest)
None
How do methylxanthines work
Research indicates that methylxanthines increase cGMP and cAMP by inhibiting phosphodiesterase and blocking adenosine receptors
What are the physiologic effects of caffeine
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
What are the adverse effects of chronic caffeine use
At low dose—Insomnia and agitation can occur
At higher doses (8-10g)—Emesis, convulsions, and even cardiac arrhythmias can occur
None
Do methylxanthines cross the placenta
Yes, and they are secreted into the mother’s milk. Patients should be advised to avoid them during pregnancy and while nursing
What is the therapeutic role of theophylline
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
How are the physiological effects of nicotine related to the dose
In low doses, nicotine causes ganglionic stimulation by depolarization. At high doses is causes ganglionic blockade
What are the physiologic actions of nicotine on the CNS
At low doses—arousal, relaxation, and improved attention
At high doses—central respiratory paralysis caused by disruption of medullary function
None
How does nicotine affect the peripheral nervous system
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
What are nicotine’s therapeutic uses
Nicotine has no therapeutic uses
What is nicotine’s rout of administration
Absorption occurs through oral mucosa, by inhalation, and transdermally
What are nicotine’s adverse effects
CNS—irritability and tremors
Peripheral—intestinal cramps, diarrhea, and increased heart rate and blood pressure
None
What withdrawal symptoms do nicotine addicts experience
A craving for tobacco is accompanied by irritability, restlessness, anxiety, and gastrointestinal pain
Name three examples of amphetamines
Methylphenidate (Ritalin)
Methamphetamine (Methedrine)—“speed”
Dextroamphetamine (Dexedrine)
None
How do amphetamines work
Amphetamines work by releasing neuronal stores of catecholamines, especially norepinephrine and dopamine
What are the physiologic actions of amphetamines
Euphoria
Decrease in fatigue
Increase in blood pressure
Increase in rate of respiration
Decrease in appetite
None
What is the clinical use of amphetamines
ADHD—Methylphenidate is used to alleviate this problem
Appetite control—Amphetamines decrease appetite by blocking the receptors in the lateral hypothalamus
Narcolepsy
None
What is the route of administration for amphetamines
Oral
Where are amphetamines metabolized
In the liver
Does physiologic and psychological dependence occur with amphetamine use
Yes—amphetamines can be very addictive
What are the adverse effects of amphetamines
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
Amphetamines are contra-indicated with what group of drugs
The MOA inhibitors
How is amphetamine overdose managed
Chlorpromazine is beneficial in amphetamine overdose because it blocks the α receptors which are responsible for the CNS disturbances and hypertension
What is the mechanism of action of amphetamines
Increases the release of catecholamines from presynaptic nerve endings
What is cocaine’s mechanism of action
Cocaine blocks the reuptake of norepinephrine, serotonin, and dopamine into presynaptic nerve terminals. This blockade results in enhanced activity of these neurotransmitters
What physiologic changes occur as a result of cocaine use
Cocaine causes mydriasis, increases heart rate, alertness, and self confidence, and induces a temporary state of euphoria by stimulating the limbic system
What are the signs of cocaine overdose
Excitation
Hallucinations and psychosis
Seizures
Respiratory depression
Arrhythmias secondary to coronary vasospasm
Coma
None
Does cocaine have any clinical use
Yes—it is used as a local anesthetic and vasoconstrictor during ENT procedures