| DEXCHLORPHENIRAMINE MALEATE
Classifications: antihistamine; h1-receptor antagonist; Therapeutic: antihistamine; h1-receptor antagonist
Pregnancy Category: B
2 mg tablets; 4 mg, 6 mg sustained release tablets; 2 mg/5 mL syrup
H1-receptor antagonist that competes for H1-receptor sites on cells, thus blocking histamine release.
Has high antihistamine effects and moderate anticholinergic effects.
Perennial and seasonal allergic rhinitis, other manifestations of allergy, and vasomotor rhinitis. Also as adjunct to epinephrine
in treatment of anaphylactic reactions.
Hypersensitivity to antihistamines of similar class; closed-angle glaucoma; acute asthmatic attack, lower respiratory tract
symptoms, newborns, premature infants, children <2 y.
Increased intraocular pressure; prostatic hypertrophy; hyperthyroidism; asthma, COPD; renal, hepatic, and cardiovascular
disease; serious GI disorders; older adults; pregnancy (category B), lactation.
Route & Dosage
Adult: PO 2 mg q46h or 46 mg of repeat-action tablets h.s. or q810h during the day
Child: PO 25 y, 0.5 mg q46h (max: 3 mg/24 h); 611 y, 1 mg q46h (max: 6 mg/24 h) or 4 mg of repeat-action tablets h.s.
- Ensure that sustained release form of drug is not chewed or crushed. It must be swallowed whole.
- Give regular tablet whole or crushed and taken with fluid or mixed with food.
- Give medication with food, water, or milk to lessen GI distress.
- Store at 15°30° C (59°86° F) unless otherwise directed.
Adverse Effects (≥1%)CNS: Drowsiness,
dizziness, weakness, headache, excitation, neuritis
, disturbed coordination, insomnia
, euphoria, paresthesias. Special Senses:
Vertigo, tinnitus, acute labyrinthitis; blurred vision. CV:
Palpitations, tachycardia, hypotension, extrasystoles. GI:
Nausea, vomiting, anorexia, dry mouth, constipation
, diarrhea. Urogenital:
Difficulty in urinating, urinary retention,
urinary frequency, early menses. Hematologic: Agranulocytosis
(rare), hemolytic or hypoplastic anemia. Skin:
Skin eruptions, photosensitivity.
Diagnostic Test Interference
In common with other antihistamines, dexchlorpheniramine may interfere with skin tests for allergy; discontinue dexchlorpheniramine at least 72 h before tests.
and other cns depressants
, mao inhibitors
compound CNS depression
Readily from GI tract. Onset:
1530 min. Peak:
3 h. Distribution:
Small amounts into breast milk. Metabolism:
In liver. Elimination:
In urine within 24 h.
Assessment & Drug Effects
- Supervise ambulation and take safety precautions, especially with older adult patients.
- Monitor I&O and assess for difficulty voiding (e.g., frequency or retention).
Patient & Family Education
- Swallow timed or sustained release tablet whole. Do not break, crush, or chew.
- Do not drive or engage in other potentially hazardous activities until reaction to drug is known.
- Ask physician about the use of alcohol, tranquilizers, sedatives, or other CNS depressants because the effects of dexchlorpheniramine
will be additive.
- Discontinue dexchlorpheniramine about 4 d before skin tests for allergies, since it can make test results inaccurate.