Topical antihistamine / mast cell stabiliser (allergic conjunctivitis) Pregnancy: SPC §4.6: not recommended during pregnancy, or in women of childbearing potential not using contraception. There are no or limited data in pregnant women, and animal studies have shown reproductive toxicity following systemic administration. Breast-feeding: should not be used — animal data show excretion of olopatadine in milk after oral administration and a risk to the newborn/infant cannot be excluded.

Olopatadine 0.1% Eye Drops (Opatanol)

Brand names: Opatanol

Olopatadine eye drops (Opatanol) are a topical ophthalmic antiallergic agent with dual antihistamine and mast cell stabilising activity, used to treat allergic conjunctivitis.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: One drop in the conjunctival sac of the affected eye(s)

Route: Ocular use only (eye drops, solution)

Frequency: Twice daily (8 hourly)

SPC §4.2. Treatment may be maintained for up to four months, if considered necessary. Elderly: no dosage adjustment is necessary. Paediatric population (non-numeric — no per-kg dose is stated): olopatadine may be used in paediatric patients three years of age and older at the same dose as in adults; safety and efficacy in children aged under 3 years has not been established and no data are available. Method of administration: after the bottle cap is removed, if the tamper-evident snap collar is loose, remove it before using the product; to prevent contamination of the dropper tip and solution, do not touch the eyelids, surrounding areas or other surfaces with the dropper tip; keep the bottle tightly closed when not in use. In case of concomitant therapy with other topical ocular medicines, an interval of five minutes should be allowed between successive applications, and eye ointments should be administered last. The product contains benzalkonium chloride — patients should remove contact lenses before use and reinsert them 15 minutes afterwards (§4.4). Note: the fetched §4.2 text does not itself state the product strength. Dose quote — SPC §4.2: 'The dose is one drop of Olopatadine Eye drops, Solution in the conjunctival sac of the affected eye(s) twice daily (8 hourly). Treatment may be maintained for up to four months, if considered necessary.'

Dose adjustments

Renal

SPC §4.2: olopatadine eye drops have not been studied in patients with renal or hepatic disease; however, no dosage adjustment is expected to be necessary in hepatic or renal impairment.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substance or to any of the excipients (SPC §4.3)

Side effects

Eye pain — the most frequent treatment-related reaction (overall incidence 0.7%); common alongside eye irritation, dry eye and abnormal sensation in the eyes
Headache and dysgeusia — common
Nasal dryness — common; fatigue — common
Uncommon: corneal erosion, corneal epithelium defect/disorder, punctate keratitis, keratitis, corneal staining, eye discharge, photophobia, blurred vision, reduced visual acuity, eye pruritus, eyelid oedema, ocular hyperaemia; also rhinitis, dizziness, hypoaesthesia, contact dermatitis, skin burning sensation, dry skin
Not known: hypersensitivity, swelling face, somnolence, corneal oedema, eye swelling, conjunctivitis, mydriasis, dyspnoea, sinusitis, nausea, vomiting. Approximately 4.5% of patients can be expected to experience adverse reactions; corneal calcification has been reported very rarely with phosphate-containing eye drops in patients with significantly damaged corneas.

Interactions

No interaction studies with other medicinal products have been performed (SPC §4.5)
In vitro, olopatadine did not inhibit metabolic reactions involving cytochrome P450 isozymes 1A2, 2C8, 2C9, 2C19, 2D6, 2E1 and 3A4 — metabolic interactions with concomitantly administered active substances are unlikely (SPC §4.5)
Other topical ocular medicines — allow an interval of five minutes between successive applications; administer eye ointments last (SPC §4.2)

Clinical monograph

How it works

It is a selective histamine H1-receptor antagonist that also inhibits the release of inflammatory mediators from mast cells, relieving the itching and redness of ocular allergy.

Prescribing in practice

It provides both rapid symptom relief and a preventive effect, but is not a treatment for ocular infection and the underlying allergic trigger should be addressed where possible.
Contact lenses should be removed before instillation if the eyes are red, and the preservative may be absorbed by soft lenses.
Transient blurred vision after instillation may temporarily affect tasks such as driving.

Monitoring

Treatment is monitored clinically by reviewing symptom control during the period of allergen exposure.

Counselling the patient

The drops both relieve and help prevent allergy symptoms, so use them as your clinician directs.
Wait until any temporary blurring clears before driving or operating machinery.
Remove contact lenses before use and follow advice on when to reinsert them.

Evidence & guidelines

Dual-acting antihistamine and mast cell stabiliser drops are an established treatment for allergic conjunctivitis, supported by clinical trials and the SPC.

Reference: Opatanol SPC; BSACI Allergic Conjunctivitis Guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways