Aller-Chlor, Chlo-Amine, Chlor-Trimeton, Chlor-Tripolon , Novopheniram , Phenetron, Telachlor, Teldrin, Trymegan
Classifications: antihistamine (h1-receptor antagonist); Therapeutic: antihistamine; h1-receptor antagonist
Pregnancy Category: B first and second trimester; D third trimester
2 mg, 4 mg tablets; 8 mg, 12 mg sustained-release tablets; 2 mg/5 mL syrup
Antihistamine that competes with histamine for H1-receptor sites on effector cells; thus it prevents histamine action that promotes capillary permeability and edema formation
and constrictive action on respiratory, gastrointestinal, and vascular smooth muscles. Produces less drowsiness than other
Has effective antihistamine reaction resulting in decreasing allergic symptomatology.
Symptomatic relief of various uncomplicated allergic conditions; to prevent transfusion and drug reactions in susceptible
patients, and as adjunct to epinephrine and other standard measures in anaphylactic reactions.
Hypersensitivity to antihistamines of similar structure; lower respiratory tract symptoms, narrow-angle glaucoma, obstructive
prostatic hypertrophy or other bladder neck obstruction, GI obstruction or stenosis; pregnancy (category B in first and
second trimester and category D in third trimester), premature and newborn infants; during or within 14 d of MAO INHIBITOR therapy.
Convulsive disorders, increased intraocular pressure, hyperthyroidism, cardiovascular disease, hepatic disease; BPH; GI
obstruction; hypertension, diabetes mellitus, history of bronchial asthma, COPD, older adult patients, patients with G6PD
Route & Dosage
|Symptomatic Allergy Relief
Adult: PO 24 mg t.i.d. or q.i.d. or 812 mg b.i.d. or t.i.d. (max: 24 mg/d)
Geriatric: PO 4 mg q.d. or b.i.d. or 8 mg sustained-release h.s.
Child: PO 612 y, 2 mg q46h (max: 12 mg/d); 26 y, 1 mg q46h
- Give on an empty stomach for fastest response.
- Sustained-release tablets should be swallowed whole and not crushed or chewed.
- Ensure that chewable tablets are chewed or crushed before being swallowed with a liquid.
Adverse Effects (≥1%) Body as a Whole:
Sensation of chest tightness. CV:
Palpitation, tachycardia, mild hypotension or hypertension. GI:
Epigastric distress, anorexia, nausea, vomiting, constipation
, or diarrhea
. CNS: Drowsiness,
sedation, headache, dizziness, vertigo, fatigue
, disturbed coordination, tremors, euphoria, nervousness, restlessness,
. Special Senses: Dryness of mouth,
nose, and throat, tinnitus, vertigo, acute labyrinthitis, thickened bronchial secretions, blurred vision, diplopia
Urinary frequency or retention, dysuria.
Diagnostic Test Interference
Antihistamines should be discontinued 4 d before skin testing procedures for allergy because they may obscure otherwise positive reactions.
Interactions Drug: Alcohol (ethanol)
and other cns depressants
produce additive sedation and CNS depression
Well absorbed from GI tract; about 45% of dose reaches systemic circulation intact. Onset:
Within 6 h. Peak:
26 h. Distribution:
Highest concentrations in lung, heart, kidney, brain, small intestine, and spleen. Metabolism:
By CYP3A4. Half-Life:
Assessment & Drug Effects
- Monitor for CNS depression and sedation, especially when chlorpheniramine is given in combination with other CNS depressants.
- Monitor BP in hypertensive patients since chlorpheniramine may elevate BP.
Patient & Family Education
- Avoid driving a car and other potentially hazardous activities until drug response has been determined.
- Avoid or minimize alcohol intake. Antihistamines have additive effects with alcohol.
- Report any of the following: tinnitus or palpitations.
- Consult physician before taking additional OTC drugs for allergy relief.