section name header

Pronunciation

dye-fen-HYE-dra-meen

Classifications

Therapeutic Classification: allergy, cold and cough remedies, antihistamines, antitussives

Indications

BEERS REMS


Action

  • Antagonizes the effects of histamine at H1-receptor sites; does not bind to or inactivate histamine.
  • Significant CNS depressant and anticholinergic properties.
Therapeutic effects:
  • Decreased symptoms of histamine excess (sneezing, rhinorrhea, nasal and ocular pruritus, ocular tearing and redness, urticaria).
  • Relief of acute dystonic reactions.
  • Prevention of motion sickness.
  • Suppression of cough.

Pharmacokinetics

Absorption: Well absorbed after oral or IM administration but 40–60% of an oral dose reaches systemic circulation due to first-pass metabolism.

Distribution: Widely distributed. Crosses the placenta; enters breast milk.

Metabolism/Excretion: 95% metabolized by the liver.

Half-Life: 2.4–7 hr.

Time/Action Profile

(antihistaminic effects)

ROUTEONSETPEAKDURATION
PO15–60 min2–4 hr4–8 hr
IM20–30 min2–4 hr4–8 hr
IVrapidunknown4–8 hr



Contraind./Precautions

Contraindicated in:

Use Cautiously in:

Adv. Reactions/Side Effects

CV: hypotension, palpitations

Derm: photosensitivity

EENT: blurred vision, tinnitus

GI: anorexia, dry mouth, constipation, nausea

GU: dysuria, urinary frequency, urinary retention

Local: pain at IM site

Neuro: drowsiness, dizziness, headache, paradoxical excitation ( in children)

Resp: chest tightness, thickened bronchial secretions, wheezing

Interactions

Drug-drug:

Drug-Natural Products:

Route/Dosage

Availability

(Generic available)

Assessment

Lab Test Considerations:

Implementation

IV Administration:

Patient/Family Teaching

Evaluation/Desired Outcomes

US Brand Names

AllerMax, Banophen, Benadryl Dye-Free Allergy, Benadryl Allergy, Benadryl, Compoz, Compoz Nighttime Sleep Aid, Diphen AF, Diphen Cough, Genahist, 40 Winks, Hyrexin-50, Maximum Strength Nytol, Maximum Strength Sleepinal, Midol PM, Miles Nervine, Nighttime Sleep Aid, Nytol, Scot-Tussin Allergy DM, Siladril, Silphen, Sleep-Eze 3, Sleepwell 2-night, Sominex, Snooze Fast, Sominex, Tusstat, Twilite, Unisom Nighttime Sleep-Aid

Canadian Brand Names

Aller-Aide, Allerdryl, Allergy Formula, Allernix, Benylin, Calmex, Dimetane Allergy, Diphenhist, Dormex, Dormiphen, Insomnal, Nadryl

Code

NDC Code