Antihistimine administered after epinephrine in the treatment of anaphylaxis; blocks histimine receptors. When stimulated H1 receptors cause bronchoconstriction and contraction of the gut and H2 receptors produce perpheral vasodilation and secretion of gastric acids.
Mechanism of Action
Diphenhydramine is a potent antihistamine that blocks both histimine receptors (H1 and H2)
Anaphylaxis, allergic reactions, urtcaria, extrapyramidal (EPS) reaction-A response to a drug marked by uncontrolled movements, changes in muscle tone, and abnormal posture.
Benadryl should not be used in the management of lower-respiratory diseases such as asthma.
Hypotension, headache, palpatations, and tachycardia have been known to occur following administration of Benadryl. Sedation, drowsiness, and disturbed coordination are common.
Dosage and Administration
Standard dose of Benadryl is 25.0-50.0mg
For antihistimine effects: 12.5-25mg IM followed by 12.5-25mg IV