Diphenhydramine Flashcards
Brand
Class
Benadryl
Antihistamine
Anticholinergic
Mech of action
Blocks cellular histamine receptors, but does not prevent estimating release; results in decreased capillary permeability and decreased the vasodilation, as well as prevention of bronchospasm. Has some anti-cholinergic effects
Indications
Anaphylaxis (2nd line)
Phenothiazine reactions (extrapyramidal symptoms)
Antiemetic
Contraindications
Known hypersensitivity to diphenhydramine or drugs of similar chemical structure.
Newborn or premature infants; nursing mothers
Considerable caution in patients with glaucoma, acute narrow angle; stenosing or obstructive disease of the GI tract; bronchial asthma; hyperthyroidism; cardiovascular disease for hypertension; age greater than 60 years.
Adverse reactions
CV: hypertension; applications; years; anemia
Resp: anaphylaxis, thickening of bronchial secretions, tightness in the chest, wheezing and nasal stuffiness
CNS: sedation, visual disturbances and seizures
GU/GI: urinary frequency or retention, vomiting
CHILDREN: may cause paradoxical CNS excitation, seizures, palpation and thickening of bronchial secretions
Notes of administration
Incompatibilities/ drug interactions
Addictive effects with alcohol and other CNS depressants (hypnotics, sedatives, transquilizers)
MAO inhibitors prolong and intensify anticholinergics effects
Adult dosage
MINOR ALLERGIC REACTION: 25mg slow IVP or deep IM
ANAPHYLAXIS: 50mg slow IVP or deep IM
EXTRAPYRAMIDAL SYMPTOMS AND ANTIEMETIC: 50mg IV or deep IM, dose should be individualized according to the needs and patient response
Ped dose
Allergy/anaphylaxis: 1.0-2.0mg/kg slow IVP
may also be given deep IM
Route
Onset
Peak effect
IV, deep IM
IV 5-10 min
1 hour
Duration
Dosage forms/packaging
AZ drug box supply
3-6 hours
50mg/ ml syringes and vials
Paramedic: 1 - unit
