Respiratory Flashcards
Antihistamines- Therapeutic uses
Therapeutic Uses-
Mild allergy/Seasonal allergic rhinitis
Severe allergy
Benefits may be limited, use as adjunct only,
Motion sickness,
Insomnia,
Common cold
Anticholinergic effects decrease rhinorrhea. Not cure to treat symptoms
Antihistamines- Adverse Effects
Sedation(First generation more than second and third generations)
Dizziness, incoordination, confusion, fatigue, GI upset
(Take with food)
Anti-cholinergic effects-Drying of mucus membranes, Urinary hesitancy, constipation, palpitations
Promethazine (Respiratory depression and local tissue injury-IV site)
Paradoxical reaction in kids - sedative purposes, and now kids are wired- nervousness, insomnia, tremors
ex: Benadryl
Antihistamine- Drug Interactions
ETOH Barbiturates Benzodiazepines Opioids Sedatives CNS depressants Tricyclic antidepressants MAO inhibitors Ototoxic drugs
Space medication administration out to avoid interactions
What is histamine?
Locally acting compound Effects vary by system High levels in skin, lungs and GI tract Low levels in plasma Can be used in diagnostic procedures
What happens in response to histamine?
H1 receptors (Skin & lungs) Vasodilation (BP& Total peripheral resistance goes down) Increased capillary permeability = edema Bronchoconstriction CNS effects Itching Secretion of mucus H2 Receptors Secretion of gastric acid- Histamine dominant over acetylcholine and gastrin
Pharmacologic Effects of Blocking H1 Receptors
Prevents vasodilation(mostly face & upper body) =reducing flushing
Decreased capillary permeability=reducing edema
Increased drowsiness
Decreased bronchoconstriction
Decreased itching and pain (blocks at a sensory receptors)
Decreased mucus secretion
Antihistamines MOA
Similar histamine antagonist 1 actions
First generation is more sedating ex: Benadryl
Second generation is much less sedating ex: Zyrtec, Claritin, Allegra
Selectively bind to H1-histamine receptors
Antihistamines- Contraindications/ Warnings
Pregnancy
Reports of fetal malformations
Benefits vs. risks
Avoid in 3rd trimester- newborns and infants are very sensitive to antihistamines
Lactation
Excreted in breast milk
Acute toxicity
Dilated pupils, flushed face, hyperpyrexia,
tachycardia, dry mouth, urinary retention
In kids CNS excitation
Can progress to coma, cardiovascular collapse and
death
Diphenhydramine
First generation antihistamine- Ethanolamines
Avoid as a sedative in children- Paradoxical excitation in kids
Can be very sedating
Use lower doses if possible
Not used freely as sedative for children
If used for insomnia, potential tolerance could be built up. If used for sleeping do so occasionally not regularly.
Technically not enough to treat insomnia therapeutically.
Caution with elderly
Fexofenadine
2nd generation anithistamine Available OTC pretty safe drug Reduce doses in renal failure Avoid fruit juices 4 hours before administration and 1-2 hours after Good combination of efficacy and safety among 2nd generation drugs Given to kids as young as 6 months comes as liquid(helpful for kids)
Cetirizine
2nd generation anithistamine
Available OTC
Reduce doses in renal and hepatic impairment
Food delays absorption
More sedating than other 2nd generation antihistamines
may work best on empty, but if nauseous give with food
Levocetirizine
Available OTC
Contraindicated for children with any renal impairment
Reduce dose for mild to moderate renal impairment
More sedating than other 2nd generation antihistamines
Therefore, Take in the evening, so you won’t notice the effects as much.
given with food or not
Loratadine
2nd generation antihistamine (“big group”)
Available OTC
Food delays absorption
Dose every other day for significant renal or hepatic impairment
Extensive hepatic metabolism
Azelastine (Astelin, Astepro)
Intranasal 2nd generation antihistamine
Astelin is not approved for children under 12
Astepro is approved for children 5-11
Can cause drowsiness, nose bleeds, headaches and an unpleasant taste-all the things that happens with internasal spary
Antihistamines- Contraindications/ Warnings
Pregnancy Reports of fetal malformations Benefits vs. risks Avoid in 3rd trimester Lactation (AVOID) Excreted in breast milk Acute toxicity(d/c meds) Dilated pupils, flushed face, hyperpyrexia, tachycardia, dry mouth, urinary retention In kids CNS excitation Can progress to coma, cardiovascular collapse and death
Asthma
Chronic inflammatory disease of the airway
Caused by immune-mediated inflammation of the airway
Treatment both inflammation and bronchoconstriction
Wheezing (sense of breathlessness), tightness of chest, dyspnea, cough
COPD
Smoking causes an inflammatory reaction
pt edu: smoking cessation-slowly decrease the daily amount of cigs
Maybe chronic bronchitis, emphysema, or both
Chronic bronchitis is from hypertrophy of mucus-secreting glands in the airway epithelium
Emphysema is an enlarged airspace between the bronchioles and alveoli due to the deterioration of the surrounding walls
Chronic, progressive and mostly irreversible
prevent from getting worse
Hypoxia, excessive sputum, wheezing, dyspnea, poor exercise tolerance, chronic cough
Asthma and COPD Drug Overview
Anti-Inflammatory Agents Glucocorticoids Usually inhaled Fixed schedule Used prophylactically- prevent inflamamtion Bronchodilators Beta2 agonists Usually inhaled Fixed schedule used for long term control PRN used for acute attacks
Glucocorticoids: Therapeutic Uses
Most effective drug for long term control of airway inflammation
Suppress inflammation
Reduced bronchial hyperreactivity
Decreased airway mucus production
Decreased synthesis & release of Inflammatory mediators
Increased infiltration and activation of inflammation cells
Decreased edema in airway mucosa Inhaled First line therapy for asthma Use daily with persistent/chronic asthma More effective and safer
Oral
Moderate to severe persistent asthma
Management of acute exacerbations in asthma and COPD
Treatment should be as BRIEF as possible- otherwise use inhaled- less adverse effects
COPD-treat IV Steroids
Glucocorticoids: Adverse Effects In
Inhaled
Adrenal suppression- really large doses
Oropharyngeal candidiasis-rinse out mouth to prevent thrush
Dysphonia- damage to vocal chords
Growth suppression in children-May slow growth in children, but not height- pt ed: reassure parents still full height
Osteoporosis-Bone loss with long term use- give calcium
Glaucoma and cataracts with continuous use of high
doses- use lowest dose possible
and risk of lost airway greater than possible blindness
Oral
No significant adverse effects with doses less than 10
days
Adrenal suppression- not often but the most serious
Hyperglycemia- most often
Peptic ulcer disease
Glucocorticoids: Warnings/ Contraindications
Discontinue long term treatment slowly, not abruptly
Will not abort an acute asthma attack i.e. don’t use for acute asthma attacks
Inhaled is preferred to oral