1. First Gen. Antihistamine Drugs
    • Diphenhydramine (Benadryl)
    • Chlorpheniramine (Chlor-Trimeton)
    • Brompheniramine (Lodrane, LoHist,Bidhist)
    • Hydroxyzine (Vistaril)
    • Promethazine (Phenergan)
    • Clemastine (Tavist)
    • Cyproheptadine
    • Triprolidine (Zymine)
  2. Indications
    • Third line therapy for allergic rhinitis
    • Not as effective as INGC
  3. MoA
    • Three categories of effect;
    • Antihistamine
    • Sedative
    • Anticholinergic.
    • May shift balance from H1 receptor form to the inactive H1 receptor form thereby down regulating the H1 receptor activity
    • Blocks increased vascular permeability, pruritis, bronchial smooth muscle constriction, and can cause mucosal drying
    • May also effect eosinophil survival
  4. SEs
    • May cause CNS depression, use caution with driving.
    • Anticholinergic effects. Dry mouth, urinary retention, possible worsening of narrow angle glaucoma, confusion.
  5. Drug Interactions
    • Acetylcholinesterase inhibitors decrease effect.
    • Anticholinergics increase side effects.
    • Additive effect with central nervous system depressants.
    • May increase the arrhythmogenic effect of phenothiazines.
  6. Contra
    • Acute asthma
    • FDA has now issued a warning that use of these medications in children under 2yrs of age, has an increased mortality. “blackbox warning”.
Card Set
Antihistamines I