Diphenhydramine (benadryl)

  1. Diphenhydramine (Benadryl)
    Antihistamine, anticholinergic.
  2. Diphenhydramine (Benadryl)
    Mechanism of action
    Blocks cellular histamine receptors; decreases vasodilation; decreases motion sickness. Reverses extrapyramidal reactions.
  3. Diphenhydramine (Benadryl)
    Symptomatic relief of allergies, allergic reactions, anaphylaxis, acute dystonic reactions (Phenothiazines). Blood administration reactions; used for motion sickness, hay fever.
  4. Diphenhydramine (Benadryl)
    Asthma, glaucoma, pregnancy, hypertension, narrow angle glaucoma, infants, Pts taking MAOIs.
  5. Diphenhydramine (Benadryl)
    Adverse reactions
    Sedation, hypotension, seizures, visual disturbances, vomiting, urinary retention, palpitations, arrhythmias, dry mouth and throat, and paradoxical CNS excitation in children.
  6. Diphenhydramine (Benadryl)
    Drug interactions
    Potentiates effects of alcohol and other anticholinergics, may inhibit corticosteroid activity; MAOIs prolong anticholinergic effects of diphenydramine.
  7. Diphenhydramine (Benadryl)
    How supplied
    Tablets:25, 50mg, capsules:25, 50mg, prefilled syringes:50 or 100mg, vials:(IVorIM), elixer, 12.5mg/5mL
  8. Diphenhydramine (Benadryl)
    Dosage and administration
    • Adult: 25-50mg IM or IV or PO.
    • Pediatric: 1-2mg/kg IV, IO slowly or IM. If given PO 5mg/kg/24hrs.
  9. Diphenhydramine (Benadryl)
    Duration of action
    • Onset: 15-30 min.
    • Peak effect: 1 hour
    • Duration: 3-12 hours
  10. Diphenhydramine (Benadryl)
    special considerations
    not used in infants or in pregnancy: category B. If used in anaphylaxis, will be in conjunction with epinephrine, corticosteroids.
Card Set
Diphenhydramine (benadryl)
Paramedic Pharmacology