ALLERFIN 4/MG TAB 30/TAB

Indications

Approved Uses

Symptomatic relief of allergic conditions such as allergic rhinitis (hay fever), urticaria and other pruritic allergic skin conditions, and allergic conjunctivitis.

Off-Label Uses

Symptomatic relief of common cold (runny nose/sneezing) and short‑term nighttime sedation (not recommended routinely); antiemetic use is not a typical off‑label role for chlorpheniramine compared with other antihistamines.

Dosage & Administration

Dosing by Condition

Allergic symptoms (IR): Adults and ≥12 years: 4 mg every 4-6 hours as needed (max 24 mg/day). Children 6-11 years: 2 mg every 4-6 hours (max 12 mg/day). Children 2-5 years: 1 mg every 4-6 hours (max 6 mg/day).

Initial Dose

4 mg orally every 4-6 hours.

Maintenance Dose

4 mg orally every 4-6 hours as needed.

Maximum Dose

24mg per day in adults

Children's Dosage

Children 6-12 years: 2 mg orally every 4-6 hours, not to exceed 12 mg/day. Children 2-6 years: 1 mg orally every 4-6 hours, not to exceed 6 mg/day. Not recommended for children under 2 years.

How to Take

Oral tablet: swallow with water; may be taken with or without food.

Side Effects

Common Side Effects

Drowsiness/sedation, dizziness, dry mouth (and other anticholinergic effects such as blurred vision, constipation, urinary retention), nausea.

Side Effect Frequency

Common: sedation/drowsiness and anticholinergic effects (e.g., dry mouth, dizziness, blurred vision, constipation, urinary retention/hesitancy, nausea). Rare/serious: paradoxical CNS excitation (especially in children), blood dyscrasias, hypersensitivity reactions; frequency for severe hepatic injury is not well established.

Safety & Warnings

Contraindications

Hypersensitivity to chlorpheniramine; concurrent MAO inhibitor use (or within 14 days); use in premature infants and neonates; narrow-angle glaucoma; urinary retention/bladder neck obstruction/symptomatic prostatic hypertrophy; stenosing peptic ulcer; pyloroduodenal obstruction.

Warnings & Precautions

May cause significant drowsiness-avoid driving/alcohol/CNS depressants; use caution in glaucoma/increased IOP, asthma/COPD, prostatic hypertrophy/urinary retention, cardiovascular disease/hypertension, hyperthyroidism, and hepatic/renal impairment; paradoxical excitation may occur in children; avoid in older adults when possible due to anticholinergic burden (Beers criteria).

Age Restriction

Do not use in children <2 years (especially neonates/premature infants); for ages 2-5 years use only with healthcare provider advice; ≥6 years may use per labeled dosing.

Drug Interactions

Drug Interactions

MAO inhibitors (contraindicated/avoid); alcohol and other CNS depressants (additive sedation/respiratory depression); other anticholinergics and tricyclic antidepressants (additive anticholinergic effects).

Interaction Severity

MAJOR: MAO inhibitors (may intensify/prolong anticholinergic/CNS effects). MODERATE: other CNS depressants including alcohol, benzodiazepines, opioids, sedative‑hypnotics (additive sedation/psychomotor impairment); other anticholinergics/TCAs (additive anticholinergic effects).

Food Interaction

No restriction

Special Populations

Children

Children 6-12 years: 2 mg orally every 4-6 hours, not to exceed 12 mg/day. Children 2-6 years: 1 mg orally every 4-6 hours, not to exceed 6 mg/day. Not recommended for children under 2 years.

Storage & Patient Advice

Missed Dose

Take as soon as remembered; skip if near the time of the next dose. Do not double the dose

Stopping the Medicine

Safe to stop anytime; no tapering required

Overdose

Symptoms: marked sedation or paradoxical excitation (especially in children), anticholinergic toxicity (dry mouth, mydriasis, flushing, hyperthermia, tachycardia, urinary retention), hallucinations, seizures, coma/respiratory depression; Management: urgent medical care, activated charcoal if appropriate, supportive care (airway/ventilation, IV fluids), treat seizures (benzodiazepines), manage hyperthermia/arrhythmias per ACLS/toxicology guidance.

Patient Counseling

May cause drowsiness-avoid driving/operating machinery until effects are known; avoid alcohol and other sedatives; do not exceed recommended dose; use caution/seek advice if glaucoma, prostate enlargement/urinary retention, severe asthma/COPD, or if taking MAOIs/other anticholinergics; take with or without food and manage dry mouth with fluids/sugar‑free lozenges; seek medical advice if symptoms persist/worsen.

Monitoring Requirements

No routine monitoring required for short-term use; monitor for anticholinergic effects in elderly patients

Pharmacology

Mechanism of Action

Reversible competitive antagonism of peripheral and central H1 receptors, reducing histamine‑mediated symptoms (sneezing, rhinorrhea, pruritus) and producing sedation via CNS H1 blockade.

Duration of Effect

4-6 hours.

Half-Life

Approximately 12-43 hours (reported ranges include ~13.9-43.4 hours).

Excretion

Primarily renal (urinary) excretion, mainly as metabolites with a small fraction excreted unchanged; urinary pH can affect elimination.

Protein Binding

Approximately 70% (about 69-72%).

Product Information

Available Dosage Forms

Tablet (this product). Other chlorpheniramine dosage forms exist in some markets (e.g., syrup/oral solution; sustained‑release tablets/capsules), but injection/chewable/capsule forms are not universally available and are not supported by the verified SFDA record for ALLERFIN 4 mg tablets.

Composition per Dose

Each tablet: 4mg chlorpheniramine maleate

Generic Availability

Yes

OTC Alternatives

Second‑generation OTC antihistamines: cetirizine 10 mg, loratadine 10 mg, fexofenadine (e.g., 120 mg/180 mg) as appropriate per local labeling.

Symptom Target

Allergy, Runny Nose

Sedating

Yes

Reviewed by Al Mujtama Pharmacy Medical Review Team. Last reviewed 03-06-2026