Itchy, watery, red eyes are one of the most common hay fever complaints at the pharmacy counter — and one of the symptoms that oral antihistamines control least well. Topical ophthalmic treatments provide targeted relief that pills cannot match, but the OTC range includes several different drug classes with different mechanisms, onset times, and suitability for different patients. Selecting the right eye drop for the right patient is a practical pharmacy skill.
The options at a glance
| Eye drop | Class | Onset | Dosing | OTC? | Best for |
|---|---|---|---|---|---|
| Sodium cromoglicate 2% | Mast cell stabiliser | 3–7 days for full effect | 4× daily | Yes | Prophylaxis; patients who can plan ahead |
| Azelastine 0.05% | Antihistamine (topical) | Within minutes | Twice daily | Yes (P) | Rapid relief; moderate-severe symptoms |
| Ketotifen 0.025% | Antihistamine + mast cell stabiliser | Within minutes | Twice daily | Yes | Dual action; convenient for regular users |
| Antazoline/xylometazoline | Antihistamine + vasoconstrictor | Within minutes | 2–3× daily, max 5 days | Yes | Short-term cosmetic relief; job interviews, events |
| Olopatadine 0.1% | Antihistamine + mast cell stabiliser | Within minutes | Twice daily | POM | Prescriber-initiated; severe or refractory cases |
Sodium cromoglicate: the steady preventer
Sodium cromoglicate (Opticrom, own-brand generics) stabilises mast cells, preventing them from releasing histamine and other inflammatory mediators when allergen contact occurs. It is the longest-established OTC allergy eye drop and remains a first-line option.
Strengths:
- Very well tolerated with an excellent safety profile
- Suitable for long-term use throughout the pollen season
- Inexpensive and widely available
- Safe for children (check product age limits — most brands allow use from age 6)
Limitations:
- Slow onset — it takes several days of regular use to reach full effect
- Requires four-times-daily dosing, which is inconvenient for some patients
- Does not provide rapid relief for acute symptoms
- Preventive, not rescue — patients need to start before the season begins or maintain regular use
Best pharmacy recommendation when: The patient plans ahead, has mild-to-moderate seasonal symptoms, and wants a safe, affordable daily preventer.
Azelastine: the rapid responder
Azelastine (Optilast) is a topical antihistamine that blocks H1 receptors directly on the conjunctival surface. It works within minutes and is dosed twice daily — a significant convenience advantage over sodium cromoglicate.
Strengths:
- Rapid onset (within 3–5 minutes)
- Twice-daily dosing
- Effective for moderate-to-severe symptoms
- Can be used reactively (when symptoms flare) as well as regularly
Limitations:
- Bitter taste — azelastine drains through the nasolacrimal duct and some patients report an unpleasant taste in the mouth. This is harmless but can affect adherence
- Brief stinging on application in some patients
- More expensive than sodium cromoglicate
Best pharmacy recommendation when: The patient needs fast relief, has moderate-to-severe eye symptoms, or cannot manage four-times-daily dosing.
Ketotifen: dual action in one drop
Ketotifen (Zaditen) combines antihistamine (H1 blockade) and mast cell stabilising properties in a single molecule. It provides both rapid symptom relief and preventive mast cell stabilisation with twice-daily dosing.
Strengths:
- Dual mechanism — both immediate relief and prevention
- Twice-daily dosing
- Rapid onset like azelastine, with cumulative preventive benefit like sodium cromoglicate
- Generally well tolerated
Limitations:
- Can cause transient stinging and mild eye irritation
- Some patients report a film or temporary blurring after application
- Limited brand availability compared to sodium cromoglicate
Best pharmacy recommendation when: The patient wants the convenience of a single product that provides both immediate and preventive benefit. A practical "best of both worlds" option.
Antazoline/xylometazoline: the short-term fix
Combination drops containing an antihistamine (antazoline) and a vasoconstrictor (xylometazoline) provide rapid relief of both itch and redness by blocking histamine and constricting conjunctival blood vessels. Otrivine-Antistin is the best-known OTC example.
Strengths:
- Very rapid onset — noticeable within 1–2 minutes
- Effective at reducing visible eye redness (the vasoconstrictor effect)
- Useful for important one-off situations (presentations, social events, photographs)
Limitations:
- Maximum 5 days' continuous use. The vasoconstrictor component causes rebound redness (conjunctival hyperaemia) with prolonged use, similar to the rebound congestion seen with nasal decongestant sprays
- Not suitable for regular seasonal use
- Does not prevent future symptoms — purely symptomatic
- May mask symptoms of a more serious eye condition if used long-term
Best pharmacy recommendation when: The patient needs short-term cosmetic and symptomatic relief for a specific event. Not for daily hay fever management.
Contact lens wearers: special considerations
Many allergy eye drops contain preservatives (typically benzalkonium chloride) that are absorbed by soft contact lenses and can cause irritation or lens damage. For contact lens wearers:
- Remove lenses before applying drops and wait at least 15 minutes before reinserting
- Preservative-free formulations are available for sodium cromoglicate and some other agents — recommend these where possible
- Alternatively, apply drops in the morning and evening when lenses are out, and use preservative-free lubricant drops during the day for comfort
Combining treatments
For patients with severe allergic conjunctivitis that does not respond adequately to a single topical agent, combining treatments is reasonable:
- An oral antihistamine (cetirizine, loratadine, or fexofenadine) plus a topical eye drop provides systemic and local control
- An intranasal corticosteroid plus a topical eye drop covers both nasal and ocular symptoms
- Some patients benefit from using ketotifen or sodium cromoglicate as a regular preventer plus azelastine as needed for breakthrough symptoms, though this combination is off-label
If combined therapy fails to control symptoms, referral to a GP for consideration of prescription options (olopatadine, topical corticosteroid eye drops under specialist supervision) is appropriate.
The pharmacy recommendation pathway
A simple decision tree for the counter:
- Mild symptoms, can plan ahead → Sodium cromoglicate (4× daily, start before season)
- Moderate symptoms, wants convenience → Ketotifen (twice daily, dual action)
- Moderate-severe, needs fast relief → Azelastine (twice daily, rapid onset)
- One-off event, needs quick redness relief → Antazoline/xylometazoline (max 5 days)
- Contact lens wearer → Preservative-free formulation of any of the above
PharmSee's pharmacy finder can help patients locate pharmacies with a wide range of allergy eye drops in stock, and the job listings page shows pharmacist vacancies across England.
Key points
- Oral antihistamines often do not adequately control allergic eye symptoms — topical eye drops are more effective
- Sodium cromoglicate is best for planned, long-term prevention (but needs 4× daily dosing and several days to work)
- Azelastine and ketotifen provide rapid relief with convenient twice-daily dosing
- Vasoconstrictor-containing drops (antazoline/xylometazoline) must not be used for more than 5 days
- Contact lens wearers should use preservative-free formulations or remove lenses before application
Sources: NICE CKS (Allergic rhinitis), BNF (Allergic conjunctivitis), NHS (Allergic conjunctivitis). Article reflects guidance current as of April 2026.