Schedule H

Oral, Ophthalmic

• Tablet: 1 mg

• Syrup: 1 mg/5 mL

• Ophthalmic solution: 0.025% w/v

INDICATIONS + DOSING — FOR CLINICIAN USE ONLY

Primary Indications (Approved / Standard in India)

1. Allergic Rhinitis and Chronic Allergic Conditions (Prophylaxis)

Parameter Details

Starting dose 0.5–1 mg orally twice daily

Titration Begin with 0.5 mg BD for 3–5 days in sensitive patients; increase to 1 mg BD

Usual maintenance dose 1 mg orally twice daily

Maximum dose 2 mg twice daily (rarely required; GI adverse effects increase)

Clinical notes:

• Prophylactic use only; NOT effective for acute symptom relief

• Onset of prophylactic effect may take 1–2 weeks of regular use

• Consider evening dosing if sedation problematic

• Administer with food to reduce GI upset

1. Asthma (Adjunctive Prophylaxis)

Parameter Details

Starting dose 1 mg orally twice daily

Titration Not applicable; maintain stable dosing

Usual maintenance dose 1 mg orally twice daily

Maximum dose 2 mg twice daily (less commonly used in current asthma protocols)

Clinical notes:

• NOT for acute asthma attacks or bronchospasm relief

• Should NOT replace inhaled corticosteroids or bronchodilators

• Assess response after 8–12 weeks; continue if symptomatic benefit demonstrated

• Taper slowly if discontinuing after prolonged use (avoid abrupt withdrawal)

• Second-line role in asthma; primarily considered in paediatric asthma prophylaxis

1. Allergic Conjunctivitis (Seasonal and Perennial)

Parameter Details

Starting dose 1 drop in each affected eye twice daily

Titration May increase to 1 drop four times daily in severe cases (specialist advice)

Usual maintenance dose 1 drop in each affected eye twice daily

Maximum dose 1 drop four times daily per eye

Clinical notes:

• Minimal systemic absorption with ophthalmic use

• Continue throughout allergen exposure period

• Avoid contact lens wear during acute treatment

• Wait at least 10 minutes before inserting contact lenses after instillation

• Store eye drops in cool place; discard 4 weeks after opening

Secondary Indications — Adults Only (Off-label)

Indication Dose Duration Notes

Chronic idiopathic urticaria 1–2 mg orally twice daily Variable; weeks to months OFF-LABEL; Specialist only; Used when second-generation antihistamines inadequate; Evidence: Indian case reports and consensus practice

Atopic dermatitis (pruritus control) 1 mg orally twice daily Variable; as needed for symptom control OFF-LABEL; Specialist (Dermatologist) only; Used as adjunct for nocturnal pruritus; Evidence: Specialist experience in India, small trials

PAEDIATRIC DOSING (Specialist Only)

⚠️ NOT RECOMMENDED below 6 months of age except under specialist supervision.

Primary Indications (Approved / Standard in India)

1. Allergic Rhinitis and Asthma (Prophylactic Adjunct)

Oral Syrup 1 mg/5 mL

6 months – 3 years 0.05 mg/kg orally twice daily Increase gradually based on tolerance 0.05 mg/kg twice daily 0.5 mg twice daily

3 years 1 mg orally twice daily Not applicable 1 mg twice daily 2 mg twice daily

Clinical notes:

• Onset of prophylactic effect: 2–4 weeks of regular use

• NOT for acute asthma relief or acute allergic symptoms

• Monitor for excessive sedation, especially in children <3 years

• Administer with food; evening dose may reduce daytime sedation

• Weight-based dosing for infants ensures accuracy

1. Allergic Conjunctivitis (Age ≥3 years)

Parameter Details

Starting dose 1 drop in each affected eye twice daily

Titration Not applicable

Usual maintenance dose 1 drop twice daily

Maximum dose 1 drop four times daily per eye

Clinical notes:

• Avoid in children <3 years unless supervised by paediatric ophthalmologist

• Ensure proper instillation technique; parent/caregiver education important

Secondary Indications — Paediatric Doses (Off-label)

• No reliable off-label paediatric indications documented for India

Safety Monitoring:

• Sedation level (especially in younger children)

• Weight gain with prolonged oral use

• Behavioural changes (irritability, hyperactivity)

• Appetite changes

Dialysis Not significantly dialyzed; use lowest effective dose

• Known hypersensitivity to ketotifen or any excipients

• History of epilepsy or seizure disorders (ketotifen lowers seizure threshold)

• Concurrent use with oral antidiabetics in patients with poorly controlled diabetes (theoretical concern of masking hypoglycaemia)

• Significant sedation potential, especially in initial weeks of therapy

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

• Asthma patients: not for acute symptom relief; avoid abrupt discontinuation after long-term use

• Diabetes mellitus: rare reports of altered glycaemic control; monitor blood glucose

• Patients operating machinery or driving (psychomotor impairment)

• Benign prostatic hyperplasia (anticholinergic effects)

• Narrow-angle glaucoma risk (anticholinergic effects)

• Elderly patients with reduced hepatic function

Parameter Details

Risk category Not well-established; limited human data

General safety Insufficient data to confirm safety; avoid unless clearly necessary

Preferred alternatives Cetirizine or Loratadine (more safety data in pregnancy)

When may be used Only if benefits outweigh risks; avoid first trimester if possible; specialist consultation recommended

Monitoring Fetal growth monitoring if prolonged use required

Parameter Details

Compatibility Probably compatible for short-term use

Drug levels in milk Likely low (not well quantified)

Preferred alternatives Cetirizine or Loratadine (better-established safety records)

Infant monitoring Irritability, sedation, poor feeding, unusual drowsiness

Parameter Recommendation

Starting dose 0.5 mg orally twice daily

Titration Slow and cautious; increase after 5–7 days if tolerated

Specific risks Increased susceptibility to CNS depression, falls, confusion, prolonged sedation, urinary retention

Recommendation Consider second-generation antihistamines as alternatives; use with care in hepatic impairment

Interacting Drug/Class Effect Recommendation

CNS depressants (opioids, benzodiazepines, alcohol, barbiturates) Additive sedation and CNS depression Avoid combination or significantly reduce doses; close monitoring required

MAO inhibitors Enhanced central effects; potential for excessive sedation and anticholinergic toxicity Avoid combination if possible; use with extreme caution

Oral antidiabetics (sulfonylureas, insulin) Rare reports of ketotifen masking hypoglycaemia symptoms Monitor blood glucose closely; counsel patients on hypoglycaemia recognition

Interacting Drug/Class Effect Recommendation

Anticholinergic drugs (TCAs, oxybutynin, ipratropium) Additive anticholinergic effects (dry mouth, urinary retention, constipation, blurred vision) Monitor for anticholinergic burden

Antiepileptics (phenytoin, carbamazepine, valproate) Ketotifen may lower seizure threshold Use cautiously; monitor seizure control

Beta-agonists (salbutamol, terbutaline) May potentiate tremors Monitor in children; usually manageable

Antihistamines (other sedating types) Additive sedation Avoid duplication; monitor

TB drugs (isoniazid, ethambutol) No specific pharmacokinetic interaction; sedation may be compounded Monitor for excessive sedation

• Drowsiness / sedation (very common, especially in early therapy)

• Dry mouth

• Dizziness

• Weight gain (mild; with prolonged oral use)

• Increased appetite

• Headache

• Nausea

• Irritation or stinging (ophthalmic formulation)

Adverse Effect Clinical Notes

Seizures Rare; especially in patients with predisposing factors — avoid in epilepsy

Hepatic dysfunction Rare; monitor LFTs in prolonged use

Severe hypersensitivity / Anaphylaxis Very rare; discontinue immediately

Thrombocytopenia Very rare; discontinue if confirmed

Severe ocular reactions (ophthalmic use) Blurred vision, severe eye pain — discontinue and refer to ophthalmologist

Phase Parameters

Baseline None routinely required unless comorbidities present; assess seizure history

After initiation Monitor sedation levels within first 1–2 weeks (especially in children and elderly); assess clinical response

Long-term Weight monitoring (if prolonged oral use); liver function tests if >3 months continuous use or symptoms suggestive of hepatic dysfunction; seizure risk in predisposed patients

• Zaditen (Novartis / Alcon)

• Ketasma (Sun Pharma)

• Allerban

• Asthafen (East West Pharma)

• Zefnil

• Tofen

Note: NOT included in NLEM 2022; prices not NPPA-controlled.

1. Prophylactic agent only — Not effective for acute allergic symptoms or asthma attacks; counsel patients to continue for at least 2–4 weeks before assessing benefit.

1. Initial sedation is common — Warn patients about drowsiness during the first 1–2 weeks; consider evening dosing to minimise daytime impairment; sedation usually decreases with continued use.

1. Gradual withdrawal after prolonged use — Especially in asthma patients; abrupt discontinuation may precipitate symptom rebound.

1. Ophthalmic formulation preferred for isolated ocular allergies — Minimal systemic absorption makes it safer and avoids oral sedation.

1. Paediatric role — Useful oral option for allergic rhinitis and asthma prophylaxis in children when second-generation antihistamines not tolerated; syrup formulation allows accurate weight-based dosing.

1. Second-line in asthma — Should not replace inhaled corticosteroids or bronchodilators; consider as add-on therapy in difficult-to-control allergic asthma.

ketotifen; antihistamine; mast cell stabiliser; allergic rhinitis; asthma prophylaxis; allergic conjunctivitis; paediatric-use; sedation-risk; eye drops; chronic urticaria; Schedule H

RxIndia v1.0 — 09 Jan 2025

• CDSCO (Drug approval database and product labels)

• National Formulary of India (NFI)

• API Textbook of Medicine

• AIIMS Formulary

• IAP Drug Formulary and Paediatric Guidelines

• Goodman & Gilman's The Pharmacological Basis of Therapeutics

• Indian dermatology and paediatric specialist practice protocols

• Manufacturer product inserts (Novartis, Sun Pharma)