Schedule H (single-ingredient formulations); OTC when in approved FDC cough/cold preparations

Oral, Intramuscular, Intravenous

• Tablets: 4 mg

• Sustained-release tablets: 8 mg

• Syrup: 2 mg/5 mL

• Oral drops: 1 mg/mL

• Injection: 10 mg/mL (1 mL ampoule)

INDICATIONS + DOSING — FOR CLINICIAN USE ONLY

Primary Indications (Approved / Standard in India)

1. Allergic Rhinitis

Adults — Oral:

Parameter Dosing

Starting dose 4 mg orally every 4–6 hours

Titration Not applicable

Usual maintenance dose 4 mg three to four times daily (12–16 mg/day)

Maximum dose 24 mg/day

Clinical Notes:

• Second-generation antihistamines (cetirizine, loratadine) preferred for chronic allergic rhinitis due to less sedation

• Administer at bedtime if sedation problematic

1. Acute Urticaria and Pruritic Dermatoses

Adults — Oral:

Parameter Dosing

Starting dose 4 mg orally every 4–6 hours

Titration Not applicable

Usual maintenance dose 4 mg three to four times daily

Maximum dose 24 mg/day

Adults — Parenteral (for severe urticaria):

Parameter Dosing

Starting dose 10 mg IM or slow IV

Titration Not applicable

Usual maintenance dose 10 mg every 6–8 hours as needed

Maximum dose 40 mg/day parenterally

Clinical Notes:

• Short-term use recommended

• Switch to oral therapy as soon as practicable

1. Anaphylaxis (Adjunctive Therapy)

Adults — Parenteral:

Parameter Dosing

Starting dose 10–20 mg IM or slow IV after epinephrine administration

Titration Not applicable

Usual maintenance dose Single dose; may repeat after 4–6 hours if urticaria/pruritus persists

Maximum dose 40 mg/day

Clinical Notes:

• NOT a substitute for epinephrine — supportive role only

• Administer only after initial stabilisation with adrenaline and fluids

• Addresses persistent urticaria and pruritus, not the life-threatening manifestations

1. Drug-Induced Allergic Reactions and Pruritus

Adults — Oral:

Parameter Dosing

Starting dose 4 mg orally every 6 hours

Titration Not applicable

Usual maintenance dose 4 mg three to four times daily

Maximum dose 24 mg/day

Duration Until resolution of symptoms; short-term use preferred

Secondary Indications – Adults Only (Off-label)

Indication Dose Duration Notes Evidence Basis

Motion sickness prophylaxis 4 mg orally 30–60 minutes before travel; repeat every 6–8 hours as needed Duration of travel exposure OFF-LABEL Historical antihistamine use; limited Indian-specific guidance

Sedation (pre-procedural) 4 mg orally 1 hour before procedure Single dose OFF-LABEL; Specialist only Tertiary care practice

PAEDIATRIC DOSING (Specialist Only)

Primary Indication: Allergic Rhinitis, Urticaria, and Allergic Dermatoses

Age-Based Dosing — Oral:

1–2 years 1 mg twice daily 1 mg twice daily 2 mg/day Oral drops

2–6 years 1 mg every 4–6 hours 1 mg every 4–6 hours 6 mg/day Syrup or drops

6–12 years 2 mg every 4–6 hours 2 mg every 4–6 hours 12 mg/day Syrup or tablets

≥12 years 4 mg every 4–6 hours 4 mg every 4–6 hours 24 mg/day Tablets

Titration: Not applicable

Primary Indication: Anaphylaxis (Adjunctive — After Epinephrine)

Paediatric — Parenteral:

Parameter Dosing

Starting dose 0.1–0.2 mg/kg IM or slow IV (after epinephrine)

Titration Not applicable

Usual maintenance dose Single dose

Maximum dose 10 mg per dose

Safety Monitoring (Paediatrics)

• Monitor for excessive sedation

• Watch for paradoxical CNS excitation (restlessness, irritability, insomnia) — more common in young children

• Assess for anticholinergic effects (dry mouth, urinary retention)

Secondary Indications – Paediatrics (Off-label)

Indication Dose Duration Notes Evidence Basis

Motion sickness (≥2 years) 0.1 mg/kg orally 30 minutes before travel; repeat every 6–8 hours Duration of exposure Specialist only – OFF-LABEL Historical use; limited paediatric data

Clear Statement: Not recommended for use in infants below 1 year of age except under paediatric specialist supervision.

• Known hypersensitivity to chlorpheniramine or other antihistamines

• Concurrent use of monoamine oxidase inhibitors (MAOIs) or within 14 days of MAOI discontinuation

• Neonates and premature infants

• Acute asthma attack or severe lower respiratory tract disease

• Angle-closure glaucoma

• Urinary retention due to prostatic hypertrophy

• Elderly patients (high anticholinergic burden; increased risk of falls, confusion, urinary retention)

• Prostatic hypertrophy (may worsen urinary symptoms)

• Epilepsy or seizure disorders (may lower seizure threshold)

• Narrow-angle glaucoma

• Cardiovascular disease (tachycardia risk)

• Pyloroduodenal obstruction

• Concurrent use of CNS depressants (alcohol, opioids, benzodiazepines)

• Driving or operating heavy machinery (sedation risk)

Parameter Details

Safety Statement Generally considered safe based on extensive historical use; no confirmed teratogenicity

Preferred alternatives Second-generation antihistamines (cetirizine, loratadine) preferred, especially for chronic therapy

When may be used Short-term use acceptable when benefit outweighs risk; avoid in first trimester if possible

What to monitor Maternal sedation, hypotension; no specific fetal monitoring required

Parameter Details

Compatible with breastfeeding Yes — low levels excreted in breast milk

Preferred alternatives Cetirizine or loratadine preferred for longer-term use (less sedating)

Expected drug levels in milk Low

What to monitor in infant Sedation, irritability, feeding difficulties, paradoxical excitation

Note: Avoid if infant is premature or has respiratory concerns.

Parameter Recommendation

Starting dose 2 mg every 6–8 hours (half the standard adult dose)

Titration Slower titration; assess tolerance before increasing

Extra risks High anticholinergic burden — increased risk of confusion, delirium, falls, urinary retention, constipation, dry mouth; avoid sustained-release formulations

Preferred alternatives Second-generation antihistamines (cetirizine, loratadine, fexofenadine) strongly preferred

Interacting Drug Effect Management

MAO inhibitors (phenelzine, tranylcypromine, selegiline) Risk of hypertensive crisis, severe anticholinergic effects, hyperpyrexia Contraindicated; do not use concurrently or within 14 days of MAOI

Alcohol Enhanced CNS depression, sedation, impaired psychomotor function Avoid concurrent use

Opioid analgesics (morphine, tramadol, codeine) Additive CNS and respiratory depression Use with caution; reduce doses of both if essential

Benzodiazepines and other sedatives Additive sedation, respiratory depression risk Avoid or use reduced doses with close monitoring

Interacting Drug Effect Management

Anticholinergic drugs (tricyclic antidepressants, atropine, oxybutynin) Additive anticholinergic effects (dry mouth, urinary retention, confusion, ileus) Monitor for anticholinergic toxicity; avoid in elderly

Antipsychotics (haloperidol, olanzapine) Additive sedation and anticholinergic effects Monitor sedation levels

Phenytoin May reduce phenytoin clearance; risk of phenytoin toxicity Monitor phenytoin levels

Rifampicin May reduce chlorpheniramine levels via CYP enzyme induction Monitor clinical response; may need dose adjustment

Ototoxic drugs (aminoglycosides) May mask early symptoms of ototoxicity (tinnitus, dizziness) Use with caution; monitor hearing

• Sedation and drowsiness

• Dry mouth

• Dizziness

• Blurred vision

• Gastrointestinal upset (nausea, constipation)

• Urinary hesitancy

• Thickening of bronchial secretions

Adverse Effect Notes

Paradoxical CNS stimulation More common in children; presents as restlessness, insomnia, excitation, seizures

Cardiac arrhythmias Rare; tachycardia, palpitations; higher risk with overdose

Acute urinary retention Especially in elderly males with prostatic hypertrophy

Seizures Rare; at high doses or in predisposed individuals

Anaphylaxis Very rare; may occur with parenteral administration (often due to excipients)

Agranulocytosis / Blood dyscrasias Very rare; discontinue if unexplained fever, sore throat, mucosal ulceration

After initiation Sedation level, blood pressure, paradoxical excitation (in children), urinary symptoms (in elderly males)

Long-term Not recommended for chronic use; if prolonged therapy unavoidable, monitor for anticholinergic burden effects

Single-ingredient formulations:

• Avil (Sanofi)

• Piriton (GSK)

• Chlorpheniramine Maleate IP (various generic manufacturers)

• Histafree (Cipla)

Common FDCs (for reference):

Note: Many FDC cough/cold preparations containing chlorpheniramine are available OTC but should be used judiciously.

NLEM Status: Listed under NLEM 2022

Government Supply: Available through Jan Aushadhi and government hospitals

• Second-generation preferred for chronic use: For allergic rhinitis and chronic urticaria, cetirizine, loratadine, or fexofenadine are preferred due to less sedation and once-daily dosing

• Sedation can be useful: The sedating property makes chlorpheniramine useful for acute pruritic conditions at night when sleep disturbance is a concern

• Paradoxical excitation in children: Young children may experience restlessness and irritability rather than sedation — warn caregivers

• Counsel about driving: Patients must be warned about impaired psychomotor function; avoid driving or operating machinery

• Avoid in elderly: High anticholinergic burden makes first-generation antihistamines poor choices for elderly patients; prefer second-generation alternatives

• Anaphylaxis role is adjunctive only: Never delay or substitute epinephrine — chlorpheniramine addresses only the histamine-mediated symptoms (urticaria, pruritus), not airway or cardiovascular collapse

chlorpheniramine; antihistamine; first-generation; urticaria; allergic rhinitis; pruritus; anaphylaxis-adjunct; sedating antihistamine; anticholinergic; NLEM India

RxIndia v1.0 — 10 Jun 2025

• CDSCO approved product information

• Indian Pharmacopoeia

• NLEM 2022

• API Textbook of Medicine, 11th Edition

• AIIMS Hospital Formulary

• IAP Guidelines for Management of Allergic Conditions in Children

• Goodman & Gilman's The Pharmacological Basis of Therapeutics

• WHO Model Formulary (supportive paediatric reference)