1301 Pharmacology Drug List
Brand Name: Benadryl
Drug Class: Antihistamines
Generic Name: diphenhydraAMINE hydrochloride
Usual Adult Dose: 25 to 50mg PO q4-6h. Max: 300mg PO daily.
Therapeutic Action: Competes with histamine for H1-receptor sites. Prevents, but
doesn't reverse, histamine-mediated responses, particularly those of the bronchia
tubes, GI tract, uterus, and blood vessels. Structurally related to local anesthetics.
(2) Major Contraindications/Cautions:
1. Contraindications in patients hypersensitive to drug; newborns; premature
neonates; breast feeding women; patients with angle-closure glaucoma, stenosing
peptic ulcer.
2. Avoid use in patients taking MAO inhibitors.
(3) Major Adverse Effects
1. CNS: drowsiness, sedation, sleepiness, dizziness, incoordination, seizures,
confusion, insomnia, headache
2. CV: palpitations, hypotension, tachycardia
3. Respiratory: thickening of bronchial secretions.
(3) Nursing Implications
1. Stop drug 4 days before diagnostic skin testing.
2. Injection form is for IV or IM administration only.
3. Don't confuse with dimenhdrinate.
(3) Client Teachings
1. Warn patient not to take this drug with any other products that contain
diphenhyramine bc of increased adverse reactions.
2. Instruct patient to take drug 30 minutes before travel to prevent motion sickness.
3. Tell patient to take diphenhydramine with food or milk to reduce GI distress.