Dose:   1 mg/kg/dose PO, IV, IM (not to exceed 5 mg/kg/day)

Frequency: Q 6 hours

Comments: Diphenhydramine is a potent antihistamine. It is useful in the treatment of mild allergic reactions to blood products, allergic skin manifestations including angioedema and urticaria, and for allergic conjunctivitis. Diphenhydramine also has anticholinergic (drying) and sedative effects. It is useful in treating drug-induced extrapyramidal side effects. The manufacturer recommends that it not be used in children weighing less than 10 pounds (Facts and Comparisons, Inc. Drug Facts and Comparisons. Olin, B.R. ed. St. Louis, MO:Facts and Comparisons, Inc; 1997, page 259). Though not used routinely in preterm infants or newborns, it has been used and is effective in the treatment of mild drug reactions.  The manufacturer also recommends against mothers breast feeding if they are treated with diphenhydramine. This appears to be due to the increased sensitivity of newborns to the drug (Briggs, Drugs in pregnancy and lactation, page 213, 1990). Roberts (Drug therapy in infants, page 350, 1984) reported no adverse effects in infants whose mothers were treated with diphenhydramine when the mother nursed prior to receiving her dose.

Preparation:
IV:  Diphenhydramine (Benadryl) is available in a 50 mg/ml concentration supplied in a single use 1 ml ampule.

PO: Diphenhydramine (Benadryl) is available in a 12.5 mg/5 ml elixir.  Stable at room temperature until expiration date.

Compatibility: No information available on filter or TPN.  It is compatible with D₅W, D₅W containing sodium chloride, LR, normal saline, acyclovir, amikacin, aminophylline, atropine, erythromycin, fentanyl, heparin, lidocaine, methicillin, metoclopramide, morphine, nafcillin, penicillin G sodium and potassium, and ranitidine.  Incompatible with amphotericin, phenobarbital, and phenytoin.