Drugs For Allergic Reactions II Flashcards
Decongestants
Phenylephrine
Pseudoephedrine
Glucocorticoids for allergic reactions
Fluticasone
Prednisone
Anticholinergics
Ipratropium
Drugs for anaphylaxis
Epinephrine
Glucocorticoids MOA
Influences protein synthesis
Annexins are synthesized; annexins inhibit PLA2 thus inhibiting the breakdown of phospholipids to arachidonic acid: this inhibits synthesis of prostaglandins & leukotrienes
Reduce # of eosinophils, basophils, mast cells in the the nasal mucosa & epithelium
Inhibit directly mediators from mast cells & basophils
Reduce mucosa edema & vasodilation
Decrease exudation
Reduce sensitivity of irritant receptors (decreased itching & sneezing)
Effective in blocking the late phase reaction which is due to migration & infiltration of inflammatory cells (eosinophils, basophils, others) caused by chemotactic factors
Onset of action takes hours
Corticosteroids are the most effective drugs available for prevention & relief of allergic rhinitis symptoms
Fluticasone administration
Intranasal
Fluticasone adverse effects
Dryness & irritation or burning of the nasal mucosa
Sore throat
Epistaxis
Headache
Prednisone adverse effects
Glucocorticoids have effects on virtually every organ in body
Systemic administration can cause numerous, at times serious side effects (reserve use for severe allergic reactions)
Significant effects include:
Suppression of HPA axis
Growth suppression
Osteoporosis
Increased intraocular pressure & cataracts
The lowest dose that prevent & control symptoms should be used for all routes
Prednisone administration
Oral
Decongestants MOA
Act as vasoconstrictors In the nasal mucosa- stimulate alpha-1 adrenergic receptors on venous sinusoids
Relieves congestion only (not effective against sneezing, itching or discharge)
Pseudoephedrine administration
Oral
Phenylephrine administration
Intranasal
Pseudoephedrine adverse effects
CNS excitation (insomnia, excitability, headache, nervousness)
Cardiovascular stimulation (palpitations, tachycardia, hypertension)
GI (nausea, vomiting)
Urinary retention
Phenylephrine adverse effects
Rebound vasodilation & congestion intranasal (rhinitis medicamentosa) when used for long periods
Nasal irritation
Pseudoephedrine contraindications
Patients w/ coronary artery disease or hypertension (alpha-1 receptor mediated vasoconstriction can worsen) Enlarged prostate (alpha-1 receptor activation compresses the urethra & decreases bladder emptying)
Ipratropium MOA
Anticholinergic
Muscarinic receptor antagonist- blocks nasal discharge (reduces nasal secretions)
Does not relieve sneezing, itching or nasal congestion
Ipratropium administration
Intranasally
Ipratropium adverse effects
Dry nose & mouth
Pharyngeal irritation
Urinary retention
Increased intraocular pressure (with inadvertent instillation in the eye)
Ipratropium contraindications
Glaucoma (blocking muscarinic receptors in the eye can increase intraocular pressure) Prostatic hypertrophy (blocking muscarinic receptors in the bladder leads to urinary retention)
Epinephrine MOA
Treatment of choice for anaphylaxis
Alpha-1 adrenergic receptor agonist causing vasoconstriction increasing systemic vascular resistance & blood pressure
Beta-adrenergic receptor agonist causing bronchodilation & increases cardiac rate contractility
Inhibits release of mediators from mast cells & basophils
Epinephrine administration
Aqueous epinephrine administered intramuscularly (thigh) or subcutaneously every 5 min. as necessary- should be used to control symptoms & increase blood pressure
Fatalities during anaphylaxis usually result from delayed administration of epinephrine & from severe respiratory complications, cardiovascular complications or both
Epinephrine contraindications
No contraindications to administration in anaphylaxis
Allergic rhinitis treatment
For mild to moderate allergic rhinitis especially for seasonal or intermittent symptoms an oral (or intranasal) second-generation H1-antihistamine would be appropriate
For moderate to severe allergic rhinitis an intranasal corticosteroid is more likely to be effective
Allergic conjuctivitis treatment
Any second-generation oral H1-antihistamine or topical ophthalmic H1-antihistamine/mast cell stabilizer would be appropriate
Atopic dermatitis treatment
Topical corticosteroid creams & ointments remain the first line choices for pharmacotherapy