Chapter 13 Central Nervous System Stimulants and Related Drugs Flashcards Preview

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Flashcards in Chapter 13 Central Nervous System Stimulants and Related Drugs Deck (38):
1

CNS Stimulants

-Drugs that stimulate a specific area of the brain or spinal cord
-Neurons contain receptors for excitatory neurotransmitters, including dopamine (dopaminergic drugs), norepinephrine (adrenergic drugs), and serotonin (serotonergic drugs)
-Sympathomimetic drugs

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Major therapeutic uses of CNS Stimulants

anti–attention deficit disorder, antinarcoleptic, anorexiant, antimigraine, and analeptic drugs

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Attention Deficit Hyperactivity Disorder (ADHD)

-Most common psychiatric disorder in children, affecting 4% to 10% of school-age children
-Boys are affected from two to nine times more often than girls.
-Drug therapy for both childhood and adult ADHD is the same.

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Narcolepsy

Incurable neurologic condition in which patients unexpectedly fall asleep in the middle of normal daily activities. These “sleep attacks” are reported to cause car accidents or near-misses in 70% or more of patients.

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Cataplexy

sudden acute skeletal muscle weakness. Associated symptom in at least 70% of narcolepsy cases. It involves sudden acute skeletal muscle weakness.

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Analeptic-Responsive Respiratory Depression Syndromes

-Neonatal apnea
-Bronchopulmonary dysplasia
-Postanesthetic respiratory depression
-Drugs: analeptic drugs such as theophylline, aminophylline, caffeine, and doxapram

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Drugs for Attention Deficit Hyperactivity Disorder (ADHD) and Narcolepsy

-Amphetamines: methylphenidate
-Nonamphetamine stimulants
Pemoline and Modafinil
Atomoxetine: nonstimulant drug that is also used to treat ADHD
Lisdexamfetamine (Vyvanse) prodrug for dextroamphetamine

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Amphetamines


Stimulate areas of the brain associated with mental alertness

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CNS effects

-Mood elevation or euphoria
-Increased mental alertness and capacity for work
-Decreased fatigue and drowsiness
-Prolonged wakefulness

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Respiratory effects

-Relaxation of bronchial smooth muscle
-Increased respiration
-Dilation of pulmonary arteries

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Adverse Effects of Stimulants

-Wide range; dose related
-Tend to “speed up” body systems
-Common adverse effects include:
Palpitations, tachycardia, hypertension, angina, dysrhythmias, nervousness, restlessness, anxiety, insomnia, nausea, vomiting, diarrhea, dry mouth, increased urinary frequency, others

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Principal Drugs Used to Treat ADHD and Narcolepsy

-Amphetamines
-Nonamphetamine stimulants
-Atomoxetine: nonstimulant drug also used for ADHD

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Atomoxetine (Strattera)

-Approved for treating ADHD in children older than 6 years of age and in adults
-In September 2005, the FDA issued a warning describing cases of suicidal thinking and behavior in small numbers of adolescent patients receiving this medication.

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Methylphenidate (Ritalin)

-First prescription drug indicated for ADHD
-Also used for narcolepsy
-Extended-release dosage forms
Ritalin SR
Concerta
Metadate CD

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Modafinil (Provigil)

-Use: improvement of wakefulness in patients with excessive daytime sleepiness associated with narcolepsy and with shift work sleep disorder
-Less abuse potential than amphetamines and methylphenidate
-Schedule IV drug
-Armodafinil (Nuvigil): similar to modafinil

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Anorexiants

-Used to treat obesity
-Anorexiants
phentermine (Ionamin)
benzphetamine (Didrex)
methamphetamine (Desoxyn)
diethylpropion (Tenuate)

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Orlistat (Xenical)

-related nonstimulant drug used to treat obesity
Mechanism of action: works locally in the small and large intestines, where it inhibits absorption of caloric intake from fatty foods.

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Mechanism of Action for Obesity Drugs

-Suppress appetite control centers in the brain
-Increase the body’s basal metabolic rate
-Mobilization of adipose tissue stores
-Enhanced cellular glucose uptake
-Reduce dietary fat absorption

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Adverse effects of obesity drugs

-Possible elevated blood pressure and heart palpitations
-Anxiety
-Agitation
-Dizziness
-Headache

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Antimigraine Drugs

Antimigraine (serotonin agonists; also called triptans)

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Ergot alkaloids

-Were the mainstay of treatment of migraine headaches but have been replaced by the triptans for first-line therapy
-Dihydroergotamine mesylate (D.H.E. 45): injectable form and as a nasal spray (Migranal)
-Ergotamine tartrate with caffeine (Cafergot): tablet form
-Narrow or constrict blood vessels in the brain

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Triptans

-Stimulate 5-HT receptors in cerebral arteries, causing vasoconstriction and reducing headache symptoms
-Reduce the production of inflammatory neuropeptides

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Adverse affects of triptans

-Vasoconstriction
-Irritation at injection site
-Tingling, flushing

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Adverse affects of Ergot Alkaloids

Nausea and vomiting
Cold or clammy hands and feet
Muscle pain
Dizziness
Others

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Sumatriptan (Imitrex)

-Original prototype drug for this class
-Seven triptans
-Slight pharmacokinetic differences exist between some of these products.
-Effects are comparable overall.

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Analeptics

-Include doxapram and the methylxanthines aminophylline, theophylline, and caffeine. Sometimes used to treat neonatal and postoperative respiratory depression.
-Used less frequently

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Doxapram (Dopram)

-Treatment of respiratory depression associated with anesthetic drugs and drugs of abuse, COPD-induced hypercapnia
-Monitor deep tendon reflexes, in addition to vital signs and heart rhythm, to prevent overdosage of this drug.

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Caffeine Found in:

-Analeptic
-Over-the-counter drugs: NoDoz
-Combination prescription drugs: Fioricet, Fiorinal
-Foods and beverages

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Caffeine Use with caution in patients with a history of:

-Peptic ulcer
-Recent myocardial infarction
-Dysrhythmias

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Methylxanthines
Mechanism of Action:

-Inhibit phosphodiesterase, leading to buildup of cyclic adenosine monophosphate (cAMP)
-Analeptic

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Caffeine
Mechanism of Action:

-Antagonizes adenosine receptors

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Analeptic Adverse Effects

-Vagal
Stimulation of gastric secretions, diarrhea, and
reflex tachycardia
-Vasomotor
Flushing, sweating
-Respiratory
Elevated respiratory rate
-Musculoskeletal
Muscular tension and tremors

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Nursing Implications:
Drugs for ADHD

-Last daily dose should be given 4 to 6 hours before bedtime to reduce insomnia.
-Take on an empty stomach 30 to 45 minutes before meals.
-Drug “holidays” may be ordered.
-Instruct parents to keep a journal to monitor the child’s response to therapy.
-Monitor the child for continued physical growth, including height and weight

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Nursing Implications:
Anorexiants

-Follow instructions for diet and exercise.
-Take in the morning.
-Avoid caffeine
-Fat-soluble vitamin supplementation may be needed.

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Nursing Implications:
Selective Serotonin Receptor Agonists (SSRAs)

-Dissolvable wafers, nasal spray, and self-injectable forms
-Provide specific teaching about correct administration.
-Instruct patients to keep a journal to monitor response to therapy.

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Nursing Implications:
Ergot alkaloids

Chest pain, confusion, slurred speech, and vision changes need immediate medical attention.

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Nursing Implications:
Analeptics

Pay close attention to the ABCs because of the patient’s diminished sensorium

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Nursing Implications:
Monitor for therapeutic responses

-ADHD: decreased hyperactivity, increased attention span and concentration
-Anorexiant: appetite control and weight loss
-Narcolepsy: decrease in sleepiness
-Serotonin agonist: decrease in frequency, duration, and severity of migraines