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Selective H1 Antihistamine + Mast Cell Stabiliser — Dual-action Antiallergic Pregnancy: Limited data — minimal systemic absorption; generally considered low risk

Olopatadine 0.1% / 0.2% Eye Drops

Brand names: Opatanol 0.1%, Pataday 0.2%

Adult dose

Dose: 0.1%: 1 drop twice daily; 0.2%: 1 drop once daily
Route: Topical (ophthalmic)
Frequency: Twice daily (0.1%) or once daily (0.2%)
Max: 1 drop per dose
Dual mechanism — selective H1 antihistamine AND mast cell stabiliser. Most widely used antiallergic eye drop in UK. Start before allergen season if seasonal allergic conjunctivitis. Remove contact lenses before instillation; wait 15 minutes before reinserting.

Paediatric dose

Route: Topical
Frequency: Twice daily
Max: Same as adult
Licensed from age 3 years (0.1% formulation); once-daily 0.2% formulation licensed from age 2 years in some countries

Dose adjustments

Renal

No adjustment — topical use

Hepatic

No adjustment

Clinical pearls

  • Dual mechanism advantage: single-agent antihistamine eye drops (e.g., antazoline) only block histamine release already occurred; mast cell stabilisers (e.g., sodium cromoglicate) only prevent degranulation — olopatadine does both, making it effective for both immediate and late-phase allergic reactions
  • Seasonal vs perennial: olopatadine is effective for both seasonal (pollen) and perennial (house dust mite, pet dander) allergic conjunctivitis — recommend starting 2 weeks before known pollen season for best effect
  • Compared to sodium cromoglicate: olopatadine provides faster symptom relief (antihistamine component) and longer lasting protection (mast cell stabilisation) — cromoglicate requires 2–4 weeks of regular use before full effect; olopatadine works from first drop
  • Contact lens wear: olopatadine contains BAK (benzalkonium chloride preservative) — soft contact lenses absorb BAK; remove lenses before drops and wait 15 minutes; prescribe preservative-free drops for contact lens wearers
  • Oral antihistamines vs topical: oral antihistamines (cetirizine, loratadine) improve systemic allergic symptoms but provide less ocular relief than topical olopatadine — combination is used for moderate-severe allergic conjunctivitis

Contraindications

  • Hypersensitivity to olopatadine
  • Contact lens wear during instillation (wait 15 minutes)

Side effects

  • Burning and stinging on instillation (mild)
  • Headache
  • Dry eye sensation
  • Blurred vision (transient)

Interactions

  • Minimal systemic absorption — no clinically significant drug interactions

Monitoring

  • Symptom response at 2 weeks
  • Eye surface if used long-term (BAK effect)

Reference: BNFc; BNF 90; NICE Allergic Rhinoconjunctivitis Guideline; SPC Opatanol / Pataday. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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