Asthma/COPD/Colds/Allergies/GI Flashcards
destruction of walls in acinus diminishing SA for gas exchange and loss of elastic recoil
emphysema
asthma is ___ inflammatory response that results in ___ bronchial hyperreactivity to various stimuli
chronic
reversible
W/ Asthma, inflammatory mediators act either directly on \_\_ or through \_\_ to produce an exaggerated bronchoconstrictive response with: 1. 2. 3. 4.
smooth muscle
neural pathways
- Edema
- Cellular infiltration
- Mucus plugs
- Epithelial denudation (late response)
describe the pathophysiology of exercise induced bronchoconstriction
-Inhalation of large volume of relatively cool, dry air alters
airway surface osmolality –> primary stimulus
-Attenuated when the inspired air is humidified and brought closer to body temperature
describe the early asthmatic response
- Immediate bronchoconstriction (↓ FEV) and vascular leakage caused by mediators from mast cells (histamine and cysteinyl leukotrienes (C4, D4).
- LTB4 and other cytokines (IL-4, IL-5, TNF [tumor necrosis factor]) are responsible for recruitment of inflammatory cells involved in the late reaction (infiltration and activation).
describe the late asthmatic response
Delayed (4-6 hrs) bronchoconstriction and bronchial hyperreactivity following epithelial damage; mediated by ECP (eosinophil cationic protein), MBP (major basic protein), and cytokines from eosinophils and neutrophils
COPD inflammation is largely mediated by
macrophages-neutrophils-CD8 T lymphocytes
what mediators result in acute bronchospasm (bronchoconstriction, microvascular leakage, mucus secretion)
acetylcholine
leukotrienes**
what mediators result in chronic inflammation hyper-reactivity (inflammatory cell infiltration and activation and epithelial damage)
leukotrienes
LTB4
eosinophils
neutrophils
5 Asthma Treatment Goals
- Control chronic symptoms (including overnight)
- Maintain normal activity (including exercise)
- Maintain normal pulmonary function
- Prevent acute episodes
- Avoid adverse medication effect
describe the mechanism of bronchodilation w/ B-adrenergic receptors for asthma and COPD tx
B2: Gs= + AC= increase cAMP= bronchial muscle relaxation
*inhale is best route due to fast onset
Side Effects of B2 adrenergic or sympathomimietic drugs
- Skeletal muscle tremor (β2 receptors)
- Tachycardia, palpitations, anxiety, insomnia (β1 receptors)
- Dry mouth (anticholinergic- M)
- Black Box Warning for salmeterol (LABA)
- Increased risk of asthma related deaths
- Should not be used without an inhaled corticosteroid
side effects of antimuscarinic agents used w/ asthma and COPD
- drying of upper mouth and airways
2. caution if comorbid glaucoma, symptomatic BPH, or bladder neck obstruction
How to glucocorticoids work
- inhibit T cell activation
- inhibit cytokine production
- inhibit eosinophil recrutiment
- inhibit mast cell migration
- inhibit mediators from eosinophils and mast cells
- vasoconstrict= reduce airway edema
*go to med bc they work everywhere
**anti-inflammatory
how to cromyolns work
- inhibit mediators from eosinophils and mast cells
- inhibit eosinophil chemotaxis
**anti-inflammatory
how to leukotriene inhibitors work
- inhibit leukotriene synthesis
- block leukotriene receptor
**anti-inflammatory
side effects of oral, parenteral corticosteriods w/ short course, high dose use?
- hyperglycemia
- sodium retention
- hypertension
- hypokalemia
- GI bleeding
- CNS distrubance
- insomnia
side effects of oral, parenteral corticosteriods w/ chronic use
- immunosuppression
- growth suppression
- thinning of skin
- osteoporosis
- cataract formation
- adrenal gland suppression
side effects of inhaled steroids
*less systemic effects but still local effects possible
- thrush
- dysphonia/hoarseness– vocal cord weakness
* 1 and 2 due to improper administration technique
HD:
- monitor for HPA axis (for adrenal gland suppression)
- bone density (osteoporosis)
- eyes (cataracts, glaucoma)
Advantages: Oral (vs inhalational administration of corticosteroids) administration increases compliance (esp. in children). Few adverse effects since __ are produced only at sites of inflammation. Relative to corticosteroids, less effect on airway symptoms / reactivity / inflammation, but equal in reducing frequency of exacerbations.
leukotriene inhibitors
Side effects of leukotriene inhibitors
- some are non-responders
- Zileuton may cause problems with liver dysfunction, so must perform regular liver function tests; must be given four times daily.
- Zafirlukast can interfere with warfarin metabolism.
• Mechanism: Anti-inflammatory action via prevention of antigen-induced release of inflammatory mediators from sensitized mast cells. Also inhibit pulmonary afferent nerve fiber receptors that contribute to cough and reflex bronchoconstriction and can suppress the activating effects of chemotactic peptides (cytokines) on neutrophils, eosinophils, and monocytes
cromolyn sodium
• Advantage: Has action to reduce both early and late phase bronchospastic response, useful in exercise-induced and antigen-induced asthma, as well as nonspecific airways reactivity. Minimal risk of systemic adverse effects
cromolyn sodium
Side effects of cromolyn sodium
- Limited to use as prophylactic agent, must be given prior to expected exposure to precipitant of asthma attack as it will NOT abort an attack once initiated;
- less effective in severe asthma.
- bronchospasm,
- wheezing,
- cough [these effects can be minimized by drinking water and/or by using of β2 agonist prior to treatment
- Mechanisms of action: Bronchodilator and anti-inflammatory via various mechanisms including:
- Inhibition of phosphodiesterase-nonselective (high concentrations)
- Effect on calcium transport
- Adenosine antagonist
- Effect on prostaglandin synthesis
Theophylline
• Advantage: Prolonged duration of action (oral) - administration at dinner can target nocturnal asthma. Rapid onset of action if given intravenously (but rarely used today).
Theophylline
Side effects of theophylline
- Low margin of safety (generally avoid switching brands),
- risk of adverse effects related to blood level:
- insomnia,
- GI disturbances (nausea, vomiting),
- headache,
- anxiety;
- seizures and
- arrhythmias (at higher levels).
- NOT available via inhalational route. Requires monitoring of serum concentration levels.
• Mechanism: Inhibition leads to increases in cAMP levels in pulmonary inflammatory cells (neutrophils, T-lymphocytes, macrophages) resulting in suppression of a myriad of inflammatory responses underlying COPD (chemotaxis, phagocytosis, and release of proinflammatory mediators [lipid mediators, cytokines, chemokines, reactive oxygen species, and hydrolytic enzymes]).
PDE-4 inhibitor
(rolumilast)
NOTE: not also a bronchodilator like theophylline (a nonselective PDE inhibitor).
• Advantage: Administered once daily via oral route. Reduces numbers of exacerbations in patients with severe COPD along with modest improvement in lung function. Reserve for refractory disease.
PDE-4 inhibitor
rolumilast
side effects of PDE-4 inhibitor
rolumilast
- Nausea and
- diarrhea most common side effects leading to discontinuation;
- weight loss in 8%.
- Psychiatric effects also observed (6% → insomnia, depression, anxiety
• Mechanism: A recombinant humanized monoclonal antibody that will bind free IgE in the circulation, preventing IgE attachment to mast cells and basophils and blocking the cellular response to allergens.
Omalizumab
• Advantages: An option for patients with moderate to severe persistent asthma, with high levels of antigen-specific IgE (i.e., a strong allergic component), who have been inadequately controlled despite maximal therapy with other asthma medications. Some studies have shown omalizumab treatment led to reduced inhaled corticosteroid use and decreased asthma exacerbations.
Omalizumab
• Mechanism: Splits disulfide linkages between mucoproteins resulting in decreased viscosity of pulmonary mucus secretions - BUT no evidence that thinning secretions induces clinical improvement. Also possesses antioxidant properties.
mucolytics
side effects of mucolytics
- trigger bronchospasm (always give w/ bronchodilator)
- N/V
- stomatitis
- rhinorrhea
black-box warning due to risk of anaphylaxis
Omalizumab
• Mechanism: Bronchodilation via action blocks vagal nerve component (parasympathetic) to oppose bronchospastic response and increased mucus secretion.
antimuscarinic agent (ipratroprium)
• Advantage: Relatively rapid onset of action. May be more effective than β-adrenergic agonists in COPD (bronchitis or emphysema)
antimuscarinic agent (ipratroprium)
in viral cold symptoms] [primary use in allergic rhinitis, minor role
antihistamines
(vasoconstrictors) [primary use in allergic
rhinitis and viral cold infections]
decongestants
[some use in coughs associated with viral
cold symptoms, allergic rhinitis, asthma, COPD]
antitussives
[some utility in viral cold infections-COPD]
expectorants
[some utility in viral cold infections-COPD]
mucolytics
describe the CV effects from histamine
H1 (increase IP3/DAG)
- vasodilation via increased No synthesis= hypotension, nasal congestion, reflex tachycardia
- increased cap. permeability (edema, hives, shock, rhinorrhea)
H2 (increased cAMP)
-cardiac stimulation and vasodilation
describe the GI effects from histamine
H1:
-SmM contraction= cramps
H2:
-increase gastric acid secretion
describe the bronchiolar SmM effects from histamine
H1:
-Bronchoconstriction— hyperactive responds in asthma
describe the neuron effects from histamine
H1
stimulate nerve endings- pain, itching
Describe the anaphylactic reaction effects from histamine
H1:
-Urticaria, abdominal cramps, laryngospasm, bronchospasm, decreased BP, shock
tx of anaphylatic rxn from histamine
Histamine plus other mediators are released from mast cells necessitating treatment with epinephrine
- Antihistamines, while effects are additive with epinephrine,
are not sufficient alone
how does cromolyn sodium affect histamine
prevents histamine release from mast cells
describe H1 receptor blocking agents for an antihistamine agent
-Reversible and competitive block with neglible H
blocking effects
1st generation agents: have additional blocking actions
at non H
2nd generation agents relatively selective for H1
receptors
uses/effects of antimuscarinic receptor blocking agents for an antihistamine agent
- Sedation (more in 1st generation bc less CNS penetration in 2nd generation)
- Prevent N/V and motion sickness: block M and H1 (1st gen. only)
- block of secretions: may be beneficial or SE: dry mouth, UR, blurred vision, constipation (1st gen only)
use of sodium channel block for antihistamine
local anesthetic action
-most often used topically first
α1-adrenergic receptor block (esp. promethazine) can cause what when used for an antihistamine
orthostatic hypotension in suspected individuals
compare 1st and 2nd generation antihistamines
1st:
- more sedation*
- more CNS penetration*
- more antimuscarinic actions*
- prevent N/V/motion sickness*
- Metabolized by liver
- short duration of action (4-8hrs)*
2nd:
- highly H1 selective
- less sedation
- no block of secretions
- no prevention of N/V/motion sickness
- less antimuscarinic actions
- longer actions (12-24 hrs)
- metabolic and/or renal elimination
2nd generation antihistamines
- fexofenadine/ Allergra
- cetirizine/ Zrytec
- loratadine/ Claritin
use of antihistamines
- allergic reactions (rhinitis and urticaria) – H1 receptor block
* 1st and 2nd generation OTC
Chronic use may diminish clinical effectiveness - can try
switch to different class)
*1st generations have additional uses
what is the best drug class to help w/ allergic disordres
antihistamines
*helps w/ sneezing, pruritus, rhinorrhea, congestion (a little)
NOT w/ inflammation
Rapid onset!
(2nd best= corticosteroids but slower onset ie.nasal steroids)
additional uses of 1st generation antihistamines
- Cough suppression (Na channel blocker)??
- Motion sickness (H1 and M block)
- N/V (H1 and M block)–Meclizine-dimenhydrinate
- Sleep aid for insomnia (H1 and M block)– diphenhydramine- doxylamine
Side effects of antihistamines
- Sedation (mostly 1st gen.)
- Additive CNS depression w/ alcohol and other CNS depressants (more with 1)
- Antimuscarinic actions: dry mouth
- paradoxical excitation
- postural hypotension
- GI: Decreased appetite, N/V, constipation