Pharmacology Chapter 13 (Unit 1) Flashcards
(32 cards)
- This is a very complex system in the human body
- Many drugs work either work in the CNS or cause adverse effects in the CNS
-CNS activity is regulated by a “checks-and- balances system”
-Excitatory and inhibitory neurotransmitters
- Receptors in the CNS
-CNS Stimulation results from either excessive stimulation or excitatory neurons or blockade of inhibitory neurons
Central Nervous System
- A broad class of drugs that stimulate specific areas of the brain or spinal cord
- Act by stimulating the excitatory neurons in the brain
- Neurons contain receptors for excitatory neurotransmitters, including dopamine (dopaminergic drugs), norepinephrine (adrenergic drugs), and serotonin (serotonergic drugs)
- Sympathomimetic drugs
Drugs are classified in 3 ways
1) Chemical structural similarities: amphetamines, serotonin agonists, symphomimetics, and xanthines
2) Site of therapeutic action in the CNS
3) Major therapeutic uses: anti-attention deficit disorders, antinarcoleptic, anorexiant, antimigraine, and analeptic drugs
CNS Stimulants
- Most common psychiatric disorder in children, affecting 10.8% of school aged children
- Boys are affected more often than girls (but girls may be underdiagnosed)
- Primary symptoms of this are inappropriate ability to maintain attention span or the presence of hyperactivity and impulsivity
- Drug therapy for both childhood and adult this are the same
- May involve predominantly attention deficit, predominantly hyperactivity or impulsivity or a combination of both
- Usually diagnosed around 7 years of age with symptoms typically appearing between 3 and 6 years
- Officially be diagnosed when symptoms last at least six months and occur at least in two different settings
Attention deficit hyperactivity disorder (ADHD)
- An incurable neurologic condition in which patients unexpectedly fall asleep in the middle of normal daily activities
-Known as “sleep attacks”
- Reportedly cause car accidents or near misses in 70% or more of patients
- Half of patients with this also experience migraine headaches
Narcolepsy
- This is sudden acute skeletal muscle weakness
- Associated symptom in at least 70% of narcolepsy cases
- It is often associated with strong emotions (ex. joy, anger) and commonly the knees buckle in the individual falls to the floor while still awake
Cataplexy
- According to the National Institutes of Health and the Centers for Disease Control and Prevention, approximately 42.2% of Americans are this
- Higher incidence in women and in minorities (Between ages 6-19 are most common)
- Being 20% or more above ones ideal body weight based on population statistics for height, body frame, and gender
-Having a BMI of 30 or greater
Health Risks include: Calorie excess, disordered metabolism, the risk for hypertension, dyslipidemia, coronary artery disease, stroke, type 2 diabetes mellitus, gallbladder disease, gout, osteoarthritis, sleep apnea, and certain types of cancer, including breast and colon cancer
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Obesity
- A common type of reoccurring headache, usually lasting from 4 to 72 hours
-Typical features: Pulsatile quality with pain that worsens with each pulse
- Most commonly unilateral but may occur on both sides of the head
-Symptoms include: Nausea, vomiting, photophobia (avoidance of light) and phonophobia (avoidance of sounds)
-Aura
Migraine
Neonatal apnea
- Common in seventy percent of premature infants born before 34 weeks gestation
-Bronchopulmonary dysplasia
-Postanesthetic respiratory depression
- Treated with analeptic drugs such as theophylline, aminophylline, caffeine, and doxapram
Analeptic- Responsive Respiratory Depression Syndromes
This condition occurs when a patient spontaneous respiratory drive does not resume adequately and in untimely manner after general anesthesia
Postanesthetic respiratory depression
-CNS stimulants are first line drugs
- They are potent drugs with a strong potential for tolerance in a psychologic dependence
-Classified as schedule 2 drugs
- Two of the oldest known stimulants are cocaine and amphetamine which are pro typical drugs for this class of drugs
Amphetamines: methylphenidates
Nonamphetamine stimulants
- Modafinil
-Atomoxetine: nonstimulant drug that is used to treat this
- Lisdexamfetamine (Vyvanse) prodrug for dextroamphetamine
Drugs for attention deficit hyperactivity disorder (ADHD) and narcolepsy
Armodafanil and Modafinil are examples of these stiulants
Nonamphetamine stimulants
- A non stimulant drug that is also used to treat ADHD
- Selective nor epinephrine reuptake inhibitor
-Has a low incidence of insomnia and a lower abuse potential
Atomoxetine
- A sulfate amphetamine derivative that was introduced for the treatment of hyperactivity in children in 1958
- Schedule 2 drug
- Used to treat ADHD and or narcolepsy
Methylphenidate
- This drug is a prodrug for deoxtroamphetamine Meaning it is converted into the body into deoxtroamphetamine
Lidexamfetamine (Vyvanse)
Mechanism of Action and drug effects
- 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
- Increase the effects of norepinephrine and dopamine in CNS synapses by increasing their release and blocking their reuptake
- Both neurotransmitters are in contact with their receptors longer which lengthens their duration of action
Indications
- includes: ADHD, Narcolepsy, and Obesity
Contraindications
-Do not take known drug allergy, cardiac structural abnomralities, and recent MAIO
Adverse Effects
-Wide range; dose related
-Tend to “speed up” body systems
-effects include: Increased heart rate and blood pressure. As well as Angina, anxiety, insomnia, headache, trimmer, blurred vision, increased metabolic rate, gastrointestinal (GI) distress, dry mouth, and worsening of or new onset of psychiatric disorders, including mania, psychoses, and or aggression
- Common adverse effects associated with atomoxetine include headache, abdominal pain, vomiting, anorexia, and cough
-Available in prescription form only for oral use
Amphetamines
- This drug is approved for treating ADHD in children older than 6 years and in adults
-Lacks addictive properties
- In September 2005 the FDA issued a warning describing cases of suicidal thinking and behavior in small numbers of adolescent patients receiving this medication
Atomoxetine (Strattera)
- This drug was the first prescription drug indicated for ADHD and is also used for narcolepsy
-Extended-release dosage forms include Ritalin SR, Concerta, and Metadate CD
- This drug increases the release and blocks the reuptake of norepinephrine and dopamine
- Schedule 2 controlled drug
Methylphenidate (Ritalin)
- This drug is used for 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 4 drug
-Armodafinil (Nuvigil): similar to this drug
Modafinil (Provigil)
- Any substances that suppress appetite
- Used to promote weight loss and obesity. Whoever their effectiveness has not yet been proven
Ex:
Phentermine (lonamin)
Benzphetamine (Regimex)
Methamphetamine (Desoxyn)
Diethylpropion (Tenuate)
- Benzphetamine and Methamphetamine are the only amphetamines currently approved for treating obesity
Mechanism of Action
- 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
Indications
- Used to treat obesity along with behavioral modifications (diet, exercise)
- Most often used in higher risk patients
Contraindications
-Do not use: Drug allergy, severe cardiovascular disease,, uncontrolled hypertension, hyperthyroidism, eating disorders, MAOI usage
Adverse Effects
- effects include: Elevated blood pressure, heart palpitations, anxiety, agitation, dizziness, headache
Anorexiants
- A anti-obesity drug that is not a CNS stimulant
- It works by inhibiting the enzyme lipase (Alli- OTC version) binds to gastric and pancreatic enzymes
- This results in reduced absorption of dietary fat from the intestinal tract and increased fat elimination in the feces
- Reduces fat absorption by roughly 30%
- Restricting dietary intake of fat to less than 30% of total calories can help reduce GI adverse effects which include oily spotting, flatulence, and fecal incontinence
- Decreases in serum concentrations of vitamins A, D, and E and beta carotene are seen as a result of blocking off fat absorption
- Supplement with fat soluble vitamins corrects this deficiency
Contraindications
Do not use: In cases of chronic malabsorption syndrome, Crohn’s disease, colitis, short bowel syndrome, and Cholestasis
Adverse Effects
effects include: Fecal incontinence with oily feces, sometimes referred to as explosive diarrhea
Orlistat (Xenical)
- This drug is a Sympathomimetic anorexiant
- Structurally related to amphetamines
- Much lower abuse potential
- Classified as a schedule 4 drug
Phentermine (Ionamin)
-Sumatriptan (Imitrex)
-Almotriptan (Axert)
-Eletriptan (Relpax)
-Naratriptan (Amerge)
-Rizatriptan (Maxalt)
-Zolmitriptan (Zomig)
- Frovatriptan (Frova)
- Lasmiditan (Reyvow)
Migraines are severe headaches thought to be due to vasodilation in the brain the (blank) stimulate (blank) causing vasoconstriction, helping to abort a migraine
Mechanism of Action
-Stimulates 5-HT receptors in cerebral arteries, causing vasoconstriction and reducing headache symptoms
-Reduce the production of inflammatory neuropeptides
- Abortive therapy for migraines
Adverse Effects
- Effects include: Vasoconstriction, coronary circulation, irritation at injection site, tingling, flushing (skin warmth and redness) and a congested feeling in the head or chest
Antimigraine/ serotonin agonists/ triptans
- These drugs 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
Mechanism of action
- Narrow or constrict blood vessels in the brain
Adverse Effects
- effects include: Nausea and vomiting, cold or clammy hands and feet, muscle pain, dizziness, numbness, vague feeling of anxiety, a bitter or foul taste in the mouth or throat, and irritation of the nose (with the nasal spray dosage form)
Antimigraine Drugs: Ergot Alkaloids
-These drugs have recently been introduced for migraine prevention and treatment
- Work by blocking the effects of CGRP
- Given by injection: erenumab (Aimvoig), Galacanezumab (Emgality), Fremanezumab (Ajovy), Eptinezumab (Vyepti)
-Given orally for acute treatment: Rimegepant and Ubrogepant (Ubrelvy)
Antimigraine Drugs: Calcitonin Gene- related Peptide Inhibitors (CGRP inhibitors)
