chlorpheniramine maleate

chlor·phen·ir·a·mine maleate (klôrfn-r-mn)

n.

An antihistamine usually used in the treatment of respiratory infections and allergic conditions.

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chlorpheniramine maleate

[-fenir′əmēn]

an antihistamine.

indications It is prescribed in the treatment of a variety of hypersensitivity reactions, including rhinitis, skin rash, and pruritus.

contraindications Asthma or known hypersensitivity to this drug prohibits its use. It is not given to newborns or lactating mothers.

adverse effects Among the more serious adverse reactions are skin rash, hypersensitivity reactions, and tachycardia. Drowsiness and dry mouth commonly occur.

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chlorpheniramine maleate (klor´fnir´mēn´mā´lēāt),

n brand names: Chlor-Trimeton, Novo-pheniram;
drug class: antihistamine H₁-receptor antagonist;
action: acts on blood vessels, gastrointestinal system, respiratory system by competing with histamine for H₁-receptor site;
uses: relief of allergy symptoms, rhinitis.

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chlorpheniramine maleate

Aller-Chlor, Allergy Relief (UK), Allerief (UK), Calimol (UK), Chlorphen, Chlor-Trimeton, Chlor-Trimeton Allergy 4 Hour, Chlor-Trimeton Allergy 8 Hour, Chlor-Trimeton Allergy 12 Hour, Chlor-Tripolon (CA), Diabetic Tussin Allergy Relief, Hayleve (UK), Novo-Pheniram (CA), Piriton (UK), Pollenase Antihistamine (UK), QDall AR, Teldrin

Pharmacologic class: Propylamine (nonselective)

Therapeutic class: Antihistamine; allergy, cold, and cough remedy

Pregnancy risk category B

Action

Antagonizes effects of histamine at histamine₂-receptor sites, preventing histamine-mediated responses

Availability

Capsules (sustained-release): 8 mg, 12 mg

Syrup: 1 mg/5 ml, 2 mg/5 ml, 2.5 mg/5 ml

Tablets: 4 mg, 8 mg, 12 mg

Tablets (chewable): 2 mg

Tablets (timed-release): 8 mg, 12 mg

⊘Indications and dosages

➣ Allergy symptoms; management of anaphylaxis and transfusion reactions

Adults: 4 mg q 4 to 6 hours P.O. or 8 to 12 mg P.O. of sustained-release form q 8 to 12 hours. Maximum dosage is 24 mg/day.

Children ages 6 to 12: 2 mg P.O. q 4 to 6 hours daily. Maximum dosage is 12 mg/day.

Dosage adjustment

• Glaucoma
• Gastric ulcer
• Hyperthyroidism
• Heart disease

Contraindications

• Hypersensitivity to drug
• Acute asthma attacks
• Stenosing peptic ulcer
• Breastfeeding

Precautions

Use cautiously in:
• hepatic or renal disease, asthma, angle-closure glaucoma, prostatic hypertrophy
• elderly patients
• pregnant patients (safety not established).

Administration

• Don't crush or break timed-release tablets or sustained-release capsules.
• Discontinue drug 4 days before allergy skin tests. (Drug may cause false-negative reactions.)

Route	Onset	Peak	Duration
P.O.	15-30 min	1-2 hr	4-12 hr
P.O. (sustained)	Unknown	Unknown	Unknown

Adverse reactions

CNS: dizziness, drowsiness, excitation (in children), sedation, poor coordination, fatigue, confusion, restlessness, nervousness, tremor, headache, hysteria, tingling sensation, sensation of heaviness and weakness in hands

CV: palpitations, hypotension, bradycardia, tachycardia, extrasystoles, arrhythmias

EENT: blurred vision, diplopia, vertigo, tinnitus, acute labyrinthitis, nasal congestion, dry nose, dry throat, sore throat

GI: nausea, vomiting, diarrhea, constipation, epigastric distress, anorexia, dry mouth, GI obstruction

GU: urinary retention, urinary hesitancy, dysuria, early menses, decreased libido, erectile dysfunction

Hematologic: hemolytic anemia, hypoplastic anemia, thrombocytopenia, leukopenia, pancytopenia, agranulocytosis

Respiratory: thickened bronchial secretions, chest tightness, wheezing

Skin: urticaria, rash, photosensitivity, diaphoresis

Other: chills, increased appetite, weight gain, anaphylactic shock

Interactions

Drug-drug. Anticholinergics, anticholinergic-like drugs (such as some antidepressants, atropine, haloperidol, phenothiazines, quinidine, disopyramide): additive anticholinergic effects

CNS depressants (such as opioids, sedative-hypnotics): additive CNS depression

MAO inhibitors: intensified, prolonged anticholinergic effects

Drug-diagnostic tests. Allergy skin tests: false-negative reactions

Drug-behaviors. Alcohol use: additive CNS depression

Sun exposure: photosensitivity

Patient monitoring

• Assess for urinary retention and frequency.
• Monitor respiratory status throughout therapy.

Patient teaching

• Advise patient to take with full glass of water.
• Tell patient not to crush timed-release tablets or sustained-release capsules. Instruct him to swallow them whole.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.
• Advise parents to give dose to children in evening, because morning doses may cause inattention in school.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and behaviors mentioned above.