DIPHENHYDRAMINE (Benadryl®) Flashcards
Generic/Trade Name
DIPHENHYDRAMINE
Benadryl®
Generic/Trade Name
Benadryl®
DIPHENHYDRAMINE
DIPHENHYDRAMINE (Benadryl®)
Drug Classification:
Antihistamine
DIPHENHYDRAMINE (Benadryl®)
Mechanism of Action:
Nonspecific competitive H1/H2 antagonist ⇒
- blocks histamine release
- suppresses central cholinergic activity
- nhibits reuptake and storage of DA, leading to prolonged action of DA and reduction of bronchoconstriction, vasodilation, increased vascular permeability
**DA =
DIPHENHYDRAMINE (Benadryl®)
Pharmacokinetics
- Onset of Action = 10-15 min (IV), 15-30 min (PO)
- Peak Effects = 1-4 hours
- Duration of Effect = 6-8 hours
- Half-Life = 1-4 hours
DIPHENHYDRAMINE (Benadryl®)
Indications & Contraindications
Indications/Field Use:
• Allergic Reaction
• Anaphylaxis
• Dystonic reactions due to phenothiazine administration (EPS)
Contraindications:
• Hypersensitivity
• Asthma
• Nursing mothers
DIPHENHYDRAMINE (Benadryl®)
Side Effects/Adverse Reactions:
Sedation, drowsiness, fatigue, euphoria
blurred vision, HA, palpitations, dizziness
dries bronchial secretions
DIPHENHYDRAMINE (Benadryl®)
Adult & Pedi Dose:
(ADULT): 25-50mg IV, IO, IM, PO
(PEDI): 1mg/kg IV, IO, IM, PO, max dose 50mg
DIPHENHYDRAMINE (Benadryl®)
Precautions:
Caution with patients with:
- severe liver disease
- asthma
- narrow angle glaucoma
- BPH (enlarged prostrate)
May cause hypotension
**BPH - Benign prostatic hyperplasia (an increase in the number of cells) resulting in the formation of large nodules in the periurethral region of the prostate that can compress the urethral canal to cause partial, or sometimes virtually complete, obstruction of the urethra.
DIPHENHYDRAMINE (Benadryl®)
Drug-Drug Interactions:
Potentiates sedative effects of:
- alcohol
- benzos
- narcotics
- TCA’s & MAOI’s
- furosemide and other anti-HTN’s
