Block V- Pulm Allergy Drugs Flashcards
What drugs all block degranulation and mediator release of Histamine?
- Isoproterenol
- Theophylline
- Epinepherine
- Cetizine
- Cromolyn
What is an accurate index of endogenous histamine levels?
N-methylhistamine in urine
Which histamine receptors are located post synaptically
H1 and H2
which histamine receptors are located presynaptically?
H3
where are all histamine receptors found?
the brain
which histamine receptors are found in the periphery?
H1 and H2
Where are H1 receptors?
Smooth muscle
endothelium
Where are H2 receptors?
gastric mucosa
cardiac muscle
vascular smooth muscle
where are H3 receptors?
presynaptic
Where are H4 receptors?
blood cells in bone marrow and circulation
-mediate chemotaxis of eosinophils and mast cells
What are the three types of drugs to block histamine actions?
- physiological antagonists
- release inhibitors
- Receptor antagonists
What are the clinical indications for H1 antagonists?
- allergic rhinitis
- utricaria
- motional sickness
- “cold pills”
- sleep aids
What are contraindications of H1 antagonist?
children under 4
What are contraindications of Fexofenadine (Allegra)
- Glaucoma
- urinary retention
- MAO inhibitors
What are contraindications of Loratadine? (claratine)
- pregnancy
- lactation
What is one of the most potent anti-histamines?
Doxepin (Sinequan)
-anti depressent
What are adverse effects of H1 blockers?
anorexia N/V constipation diarrhea epigastric distress decreased alertness impaired ability to concentrate drowsiness muscular weakness Blood dyscrasias
What are signs of H1 blocker overdose?
antichoinergic effects
-dry mouth, palpitations, chest tightness, urinary retention, visual disturbances, convulsions, hallucinations, respiratory depression, fever, hypotension, mydriasis
what are contraindications of Diphenhydramine?
-patients with asthma and COPD because of the anticholinergic actions
How do you treat mild anaphylaxis reactions?
epinephrine
- apply a tourniquet to the injection site and inject epi into the site to reduce systemic absorption of the antigen
- oral antihistamine for 24 hour
How do you treat severe anaphylaxis reactions?
- diphenhydramine IV and epinephrine
- then long acting epi
- oral antihistamine for 24 hours
How do you treat the most severe anaphylaxis reactions?
- IV fluids
- Epi slowly
- antihistamines
Which antihistamines cross the BBB?
Fexfenadine
Loratidine
Citirizine
Which antihistamines are OTC?
Diphenhydramine
Chlorpheniramine
how are HI antagonists eliminated?
hepatic elimination
Which are the first generation H1R antagonist?
- Diphenhydramine
- Chlorpheniramine
Which drug is preferred for motion sickness?
-Dimenhydrinate
Which are the second generation H1R antagonists?
- Fexofenadine
- Loratindine
- Citrizine
