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Selective H1 Antihistamine + Mast Cell Stabiliser — Dual-action Antiallergic Pregnancy: Section 4.6 verbatim: 'There are no or limited amount of data from the use of ophthalmic olopatadine in pregnant women. Studies in animals have shown reproductive toxicity following systemic administration (see section 5.3). Olopatadine is not recommended during pregnancy and in women of childbearing potential not using contraception.' Breast-feeding: 'Available data in animals have shown excretion of olopatadine in milk following oral administration (for details see section 5.3). A risk to the new-born/infants cannot be excluded. Olopatadine Eye drops, solution should not be used during breast-feeding.' Fertility: 'Studies have not been performed to evaluate the effect of topical ocular administration of olopatadine on human fertility.'

Olopatadine 0.1% / 0.2% Eye Drops

Brand names: Opatanol 0.1%, Pataday 0.2%

Olopatadine 0.1% / 0.2% eye drops are a topical dual-acting antiallergic ophthalmic preparation used to relieve the ocular signs and symptoms of allergic conjunctivitis, with the 0.2% strength formulated for once-daily use.

Adult dose

Dose: One drop of Olopatadine 1 mg/ml eye drops, solution into the conjunctival sac of the affected eye(s). Section 4.2 verbatim: '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.' The strength behind the drop is pinned by the product name: 'Olopatadine 1 mg/ml Eye drops, Solution', which is this page's 0.1% strength (1 mg per mL equals 0.1% weight/volume).
Route: Ocular (topical). Section 4.2 verbatim: 'For ocular use only. After the bottle cap is removed, if the tamper evident snap collar is loose, remove before using the product. To prevent contamination of the dropper tip and solution, care must be taken not to touch the eyelids, surrounding areas, or other surfaces with the dropper tip of the bottle. Keep the bottle tightly closed when not in use.'
Frequency: Twice daily, 8 hourly (section 4.2). Treatment may be maintained for up to four months if considered necessary.
Max: Not stated - this SPC gives no maximum dose, no maximum number of drops and no maximum daily total. The only ceiling it states is one of duration: treatment may be maintained for up to four months if considered necessary. The undesirable-effects section records the range of dosing used in clinical studies rather than a licensed maximum.
SCOPE - THIS DRAFT COVERS THE 0.1% (1 mg/ml) TWICE-DAILY STRENGTH ONLY. The only source in this bundle is the UK SPC for the 1 mg/ml product, i.e. the 0.1% strength, which is the strength this page lists first and the one this SPC licenses in the UK. NOTHING in this bundle doses the 0.2% once-daily product; that regimen is unsourced here and must not be inferred from the 0.1% wording. || ELDERLY (section 4.2 verbatim): 'No dosage adjustment in elderly patients is necessary.' || CONCOMITANT EYE MEDICINES (section 4.2 verbatim): 'In case of concomitant therapy with other topical ocular medicines, an interval of five minutes should be allowed between successive applications. Eye ointments should be administered last.' || CONTACT LENSES (section 4.4 verbatim): 'Benzalkonium chloride may be absorbed by soft contact lenses and may change the colour of the contact lenses. Patients should be instructed to remove contact lenses before using this medicine and put them back 15 minutes afterwards.' || SYSTEMIC ABSORPTION (section 4.4 verbatim): 'Olopatadine is an antiallergic/antihistaminic agent and, although administered topically, is absorbed systemically. If signs of serious reactions or hypersensitivity occur, discontinue the use of this treatment.' || INTERACTIONS (section 4.5 verbatim): 'No interaction studies with other medicinal products have been performed. In vitro studies have shown that Olopatadine did not inhibit metabolic reactions which involve cytochrome P-450 isozymes 1A2, 2C8, 2C9, 2C19, 2D6, 2E1 and 3A4. These results indicate that Olopatadine is unlikely to result in metabolic interactions with other concomitantly administered active substances.'

Paediatric dose

Route: Ocular (topical) - one drop into the conjunctival sac of the affected eye(s)
Frequency: Twice daily, 8 hourly - the same dose as in adults
Max: Not stated - no paediatric maximum dose or daily ceiling appears in this SPC.
AGE-BASED, NOT WEIGHT-BASED - dosePerKg is null because this SPC gives no mg/kg figure at any age, and concentration is null because an eye drop is not dosed by calculating a volume against a mg per mL divisor. Section 4.2 verbatim: 'Olopatadine may be used in paediatric patients three years of age and older at the same dose as in adults. The safety and efficacy of Olopatadine in children aged under 3 years has not been established. No data are available.' This applies to the 1 mg/ml (0.1%) product only; the 0.2% once-daily product is not covered by this SPC. Verify paediatric use against a children's formulary.

Dose adjustments

Renal

Section 4.2 verbatim: 'Olopatadine in the form of eye drops has not been studied in patients with renal or hepatic disease. However, no dosage adjustment is expected to be necessary in hepatic or renal impairment (see section 5.2).'

Hepatic

Section 4.2 verbatim: 'Olopatadine in the form of eye drops has not been studied in patients with renal or hepatic disease. However, no dosage adjustment is expected to be necessary in hepatic or renal impairment (see section 5.2).'

Dose independently re-sourced from UK Summary of Product Characteristics (SPC) via the eMC — clinician-reviewed. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Section 4.3 verbatim: 'Hypersensitivity to the active substance or to any of the excipients listed in section 6.1.'
  • Not a contraindication but a discontinuation rule (section 4.4): 'If signs of serious reactions or hypersensitivity occur, discontinue the use of this treatment.'
  • Not a contraindication but a precaution (section 4.4): the drops contain benzalkonium chloride, 'which may cause eye irritation, especially if patients have dry eyes or disorders of the cornea (the clear layer at the front of the eye)', and which 'has also been reported to cause punctate keratopathy and/or toxic ulcerative keratopathy'.
  • Not a contraindication but a use restriction (section 4.6): 'Olopatadine is not recommended during pregnancy and in women of childbearing potential not using contraception', and 'Olopatadine Eye drops, solution should not be used during breast-feeding.'
  • Not a contraindication but a contact-lens instruction (section 4.4): remove soft contact lenses before instillation and reinsert 15 minutes afterwards.

Side effects

  • Overall (section 4.8): 'Approximately 4.5% of patients can be expected to experience adverse reactions associated with the use of olopatadine; however, only 1.6% of patients discontinued from the clinical studies due to these adverse reactions. No serious ophthalmic or systemic adverse reactions related to olopatadine were reported in clinical studies. The most frequent treatment-related adverse reaction was eye pain, reported at an overall incidence of 0.7%.'
  • Common (at least 1 in 100 to under 1 in 10), eye disorders: eye pain, eye irritation, dry eye, abnormal sensation in eyes.
  • Common, nervous system: headache, dysgeusia.
  • Common, other: nasal dryness; fatigue.
  • Uncommon (at least 1 in 1,000 to under 1 in 100), eye disorders: corneal erosion, corneal epithelium defect, corneal epithelium disorder, punctate keratitis, keratitis, corneal staining, eye discharge, photophobia, vision blurred, visual acuity reduced, blepharospasm, ocular discomfort, eye pruritus, conjunctival follicles, conjunctival disorder, foreign body sensation in eyes, lacrimation increased, erythema of eyelid, eyelid oedema, eyelid disorder, ocular hyperaemia.
  • Uncommon, other: rhinitis; dizziness; hypoaesthesia; contact dermatitis, skin burning sensation, dry skin.
  • Not known: hypersensitivity, swelling face; somnolence; corneal oedema, eye oedema, eye swelling, conjunctivitis, mydriasis, visual disturbance, eyelid margin crusting; dyspnoea, sinusitis; nausea, vomiting; dermatitis, erythema; asthenia, malaise.
  • Very rare (section 4.8): 'Cases of corneal calcification have been reported very rarely in association with the use of phosphate containing eye drops in some patients with significantly damaged corneas.'
  • Attributable to the benzalkonium chloride preservative (section 4.4): eye irritation, punctate keratopathy and toxic ulcerative keratopathy.

Monitoring

  • Corneal surface with frequent or prolonged use (section 4.4 verbatim): 'Close monitoring is required with frequent or prolonged use in dry eye patients, or in conditions where the cornea is compromised.'
  • Patient-reported symptoms after instillation (section 4.4): if patients 'feel abnormal eye sensation, stinging or pain in the eye after using this medicine, seek medical attention immediately'.
  • Signs of serious reactions or hypersensitivity - discontinue treatment if they occur (section 4.4).
  • Duration of treatment (section 4.2): the SPC supports maintaining treatment for up to four months if considered necessary; it specifies no laboratory monitoring.

Clinical monograph

How it works

Olopatadine is a selective histamine H1-receptor antagonist that also stabilises conjunctival mast cells, reducing both the immediate histamine-mediated response and the release of further inflammatory mediators in the eye.

Prescribing in practice

  • It treats allergic eye symptoms only and is not a treatment for eye infection, so a red eye with pain, discharge or reduced vision should be reassessed rather than assumed to be allergy.
  • Contact lenses should be removed before instillation because of the preservative, and reinserted only after a short interval.
  • Confirm the strength, as the 0.1% is typically used twice daily and the 0.2% once daily.

Monitoring

Routine laboratory monitoring is not required; review symptom control and reconsider the diagnosis if redness or irritation worsens.

Counselling the patient

  • Use as a regular preventive drop during the allergy season for best effect rather than only when symptoms flare.
  • Remove contact lenses before the drop and wait a short while before putting them back in.
  • Avoid rubbing the eyes and seek review if vision changes or pain develops.

Evidence & guidelines

Dual-acting antihistamine/mast-cell-stabiliser drops are an established treatment for allergic conjunctivitis, with efficacy and tolerability supported by the SPC and ophthalmology allergy guidance.

Reference: NICE Allergic Rhinoconjunctivitis Guideline; SPC Opatanol / Pataday; 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).

Related

Curated clinical cross-links plus same-class fallbacks.

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