Exam 2 Antihistamines Flashcards
What 4 affects does histamine have on the cardiovascular system?
- Drop in BP
- Tachycardia
- Reddening of skin
- Throbbing headache
What are 2 respiratory system effects of histamine?
- Constricts respiratory smooth muscle
2. Secretion of fluid and prostaglandin formation
What 3 things does histamine affect in the GI tract?
- Secretion of HCL
- Contraction of ileum
- Increased salivary secretions
What effects do H1 antihistamines have on the body?
- Produces CNS depression (sleepiness)
- Treat motion sickness
- Block constriction of respiratory smooth muscle
- Blocks flare (wheals) and itch
What is the main role of H2 antihistamines?
Inhibits HCL release from parietal cells
4 popular H2 antihistamines
- cimetidine (Tagamet)
- famotidine (pepcid)
- nizatidine (Axid)
- ranitidine (Zantac)
If H2 is added to H1 blockers, it blocks all ____ effects of histamine
Cardiovascular
What are 4 clinical uses for H2 antihistamine?
- Peptic ulcer
- Hypersecretion of gastric acid
- GERD
- Zollinger-Ellison Syndrome
4 common side effects of antihistamines
- Sleepiness/drowsiness
- Xerostomia
- Dry mucous membranes
- Older antihistamines caused ventricular arrhythmias (non-sedating)
Name 4 clinical uses of H1 antihistamines and 5 “off label” uses
- allergic rhinitis
- pollinosis
- urticaria (localized edema with wheals)
- anaphylaxis
- motion sickness
- nausea/vomiting
- dizziness
- sleep aid
- local anesthetics
Name 3 sedating antihistamines
- diphenhydramine (Benadryl) - Ethanolamines
- chlorpheniramine (Chlor-Trimenton) - Alkylamines
- cetirizine (Zyrtec)
Name 3 non-sedating antihistamine. They have longer half life so only 1 pill per day but they take a long time to kick in plus they can cause headaches
- Ioratadine (Claritin)
- fexofenadine (Allegra)
- desloratadine (Clarinex)
What is the safest/most recommended GI antihistamine drug in this class? (fewest drug interactions)
ranitidine (Zantac)
