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Dexchlorpheniramine Maleate

Pronunciation: dex-klor-fen-AIR-uh-meen MAL-ee-ate
Class: Nonselective alkylamine

Trade Names

Dexchlorpheniramine Maleate
- Tablets, extended-release 4 mg
- Tablets, extended-release 6 mg
- Syrup, 2 mg per 5 mL

Pharmacology

Competitively antagonizes histamine H 1 at receptor sites.

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Pharmacokinetics

Absorption

C max approximately 7 ng/mL. T max approximately 3 h.

Distribution

69% to 72% protein bound.

Metabolism

Extensively metabolized.

Elimination

The t ½ is 20 to 24 h. Approximately 19% of dose is excreted in urine as parent drug and metabolites in 24 h.

Indications and Usage

Treatment of perennial and seasonal allergic rhinitis; vasomotor rhinitis; allergic conjunctivitis; mild, uncomplicated allergic skin manifestations of urticaria and angioedema; amelioration of allergic reactions to blood or plasma; dermographism; adjunctive anaphylactic therapy.

Contraindications

Treatment of lower respiratory tract symptoms; MAOI therapy; any component of the product or other antihistamines of similar chemical structure. Antihistamines also are contraindicated in newborn or premature infants, and breast-feeding mothers.

Dosage and Administration

Adults and Children 12 yr of age and older

PO Tablets : 4 or 6 mg at bedtime or every 8 to 10 h.

PO Syrup : 2 mg (1 teaspoonful) every 4 to 6 h.

Children 6 to 12 yr of age

PO Tablets : 4 mg/ day, preferably at bedtime.

PO Syrup : 1 mg (½ teaspoonful) every 4 to 6 h.

Children 2 to 5 yr of age

PO Syrup : 0.5 mg (¼ teaspoonful) every 4 to 6 h.

General Advice

  • Advise patient to swallow extended-release tablets whole and not to crush, chew, or break the tablet.
  • Measure and administer prescribed oral syrup dose using dosing syringe, dosing spoon, or dosing cup.

Storage/Stability

Store extended-release tablets and syrup between 36° and 86°F.

Drug Interactions

Alcohol, other sedatives

Will potentiate the sedative effects of dexchlorpheniramine.

MAOIs

May cause severe hypotension.

Laboratory Test Interactions

May interfere with diagnostic test results for skin tests using allergen extracts.

Adverse Reactions

Cardiovascular

Palpitations; tachycardia; extrasystoles; hypotension.

CNS

Drowsiness; headache; sedation; dizziness; vertigo; disturbed coordination; fatigue; confusion; restlessness; excitation; nervousness; tremor; irritability; insomnia; euphoria; paresthesia; hysteria; neuritis; convulsions.

Dermatologic

Urticaria; drug rash.

EENT

Tinnitus; acute labyrinthitis; blurred vision; nasal stuffiness.

GI

Dryness of mouth, nose, and throat; epigastric distress; anorexia; nausea; vomiting; diarrhea; constipation.

Genitourinary

Urinary frequency; difficult urination; urinary retention; early menstruation.

Hematologic

Hemolytic anemia; hypoplastic anemia; thrombocytopenia; agranulocytosis.

Respiratory

Thickening of bronchial secretions; tightness of chest; wheezing.

Miscellaneous

Anaphylactic shock; photosensitivity; excessive perspiration; chills.

Precautions

Monitor

Assess for allergy symptoms (eg, rhinitis, nasal congestion, sneezing, itching, watery eyes) before and periodically throughout therapy. Monitor patient for dizziness and excessive drowsiness. If noted, hold therapy.


Pregnancy

Category B .

Lactation

Undetermined.

Children

Tablet

Safety and efficacy not established in children younger than 6 yr of age.

Syrup

Safety and efficacy not established in children younger than 2 yr of age.

Elderly

More likely to have dizziness, sedation, and hypotension.

Special Risk Patients

Use with caution in patients with hypertension, heart disease, hyperthyroidism, increased IOP, diabetes mellitus, prostatic hypertrophy, bronchial asthma, narrow-angle glaucoma, stenosing peptic ulcer, pyloroduadenal obstruction, and bladder-neck obstruction.

Overdosage

Symptoms

CNS depression and stimulation (particularly in children), death, dizziness, tinnitus, ataxia, blurred vision, hypotension.

Patient Information

  • Advise patient to take each dose without regard to meals but to take with food if stomach upset occurs.
  • Advise patient using extended-release tablets to swallow tablets whole and not to crush, chew, or break the tablet.
  • Advise patient or caregiver using oral syrup to administer prescribed dose 4 times daily. Advise patient or caregiver to measure and administer prescribed dose using dosing syringe, dosing spoon, or dosing cup.
  • Advise patient if a dose is missed to take it as soon as possible unless it is nearing time for the next scheduled dose. If it is nearing time for next scheduled dose, advise patient to skip the missed dose and take the next dose at the regularly scheduled time. Caution patient not to double the dose to catch up.
  • Advise patient if allergy symptoms are not controlled, not to increase dose of medication or frequency of use but to inform health care provider. Caution patient that larger doses or more frequent dosing does not increase effectiveness and may cause excessive drowsiness or other adverse reactions.
  • Instruct patient to stop taking drug and immediately report any of these symptoms to health care provider: persistent dizziness; excessive drowsiness; severe dry mouth, nose, or throat; flushing; unexplained shortness of breath or difficulty breathing; unusual tiredness or weakness; sore throat, fever, or other signs of infection; bleeding or unusual bruising; fast or irregular heartbeat; excitability, confusion, or changes in thinking or behavior; chest tightness; difficulty with urination.
  • Advise patient medication may cause drowsiness or dizziness and not to drive or perform other activities requiring mental alertness until tolerance is determined.
  • Advise patient to take sips of water, suck on ice chips or sugarless hard candy, or chew sugarless gum if dry mouth occurs.
  • Caution patient alcohol and other CNS depressants (eg, sedatives) will have additional sedative effects if taken with dexchlorpheniramine.
  • Caution patient not to take any OTC antihistamines while taking this medication unless advised by health care provider.
  • Caution patient that medication may cause sensitivity to sunlight and to avoid excessive exposure to sun or UV light (eg, tanning booths) and to wear protective clothing and use sunscreens until tolerance is determined.
  • If patient is to have allergy skin testing, advise not to take medication for at least 4 days before skin testing.

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