Chapter 13 Central Nervous System Stimulants and Related Drugs Flashcards
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
Major therapeutic uses of CNS Stimulants
anti–attention deficit disorder, antinarcoleptic, anorexiant, antimigraine, and analeptic drugs
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.
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.
Cataplexy
sudden acute skeletal muscle weakness. Associated symptom in at least 70% of narcolepsy cases. It involves sudden acute skeletal muscle weakness.
Analeptic-Responsive Respiratory Depression Syndromes
- Neonatal apnea
- Bronchopulmonary dysplasia
- Postanesthetic respiratory depression
- Drugs: analeptic drugs such as theophylline, aminophylline, caffeine, and doxapram
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
Amphetamines
Stimulate areas of the brain associated with mental alertness
CNS effects
- Mood elevation or euphoria
- Increased mental alertness and capacity for work
- Decreased fatigue and drowsiness
- Prolonged wakefulness
Respiratory effects
- Relaxation of bronchial smooth muscle
- Increased respiration
- Dilation of pulmonary arteries
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
Principal Drugs Used to Treat ADHD and Narcolepsy
- Amphetamines
- Nonamphetamine stimulants
- Atomoxetine: nonstimulant drug also used for ADHD
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.
Methylphenidate (Ritalin)
-First prescription drug indicated for ADHD
-Also used for narcolepsy
-Extended-release dosage forms
Ritalin SR
Concerta
Metadate CD
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
Anorexiants
-Used to treat obesity
-Anorexiants
phentermine (Ionamin)
benzphetamine (Didrex)
methamphetamine (Desoxyn)
diethylpropion (Tenuate)
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.
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
Adverse effects of obesity drugs
- Possible elevated blood pressure and heart palpitations
- Anxiety
- Agitation
- Dizziness
- Headache
Antimigraine Drugs
Antimigraine (serotonin agonists; also called triptans)
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
Triptans
- Stimulate 5-HT receptors in cerebral arteries, causing vasoconstriction and reducing headache symptoms
- Reduce the production of inflammatory neuropeptides
Adverse affects of triptans
- Vasoconstriction
- Irritation at injection site
- Tingling, flushing
Adverse affects of Ergot Alkaloids
Nausea and vomiting Cold or clammy hands and feet Muscle pain Dizziness Others
Sumatriptan (Imitrex)
- Original prototype drug for this class
- Seven triptans
- Slight pharmacokinetic differences exist between some of these products.
- Effects are comparable overall.
Analeptics
- Include doxapram and the methylxanthines aminophylline, theophylline, and caffeine. Sometimes used to treat neonatal and postoperative respiratory depression.
- Used less frequently
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.
Caffeine Found in:
- Analeptic
- Over-the-counter drugs: NoDoz
- Combination prescription drugs: Fioricet, Fiorinal
- Foods and beverages
Caffeine Use with caution in patients with a history of:
- Peptic ulcer
- Recent myocardial infarction
- Dysrhythmias
Methylxanthines
Mechanism of Action:
- Inhibit phosphodiesterase, leading to buildup of cyclic adenosine monophosphate (cAMP)
- Analeptic
Caffeine
Mechanism of Action:
-Antagonizes adenosine receptors
Analeptic Adverse Effects
-Vagal
Stimulation of gastric secretions, diarrhea, and
reflex tachycardia
-Vasomotor
Flushing, sweating
-Respiratory
Elevated respiratory rate
-Musculoskeletal
Muscular tension and tremorsNursing 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
Nursing Implications:
Anorexiants
- Follow instructions for diet and exercise.
- Take in the morning.
- Avoid caffeine
- Fat-soluble vitamin supplementation may be needed.
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.
Nursing Implications:
Ergot alkaloids
Chest pain, confusion, slurred speech, and vision changes need immediate medical attention.
Nursing Implications:
Analeptics
Pay close attention to the ABCs because of the patient’s diminished sensorium
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
