Antihistamine Eye Drops: Uses and side effects

You may have no other symptoms alongside your itchy or streaming eyes, in which case eye drops are a good place to start. If you have more generalised symptoms, then antihistamine tablets can be a useful addition too. They aim to dampen down the overall immune response, which is driven by the release of histamine from mast cells.

Sodium cromoglicate 2% products, such as Opticrom eye drops, are available over-the-counter for those aged 6 and above. This active ingredient is not classed as an antihistamine but works to reduce the release of histamine in the eyes and suppress allergy symptoms there. It’s applied four times a day, and can be used as a standalone treatment or alongside oral antihistamines. The advantage of sodium cromoglicate is that it’s available to buy over-the-counter. Intranasal or eye drop antihistamines require a prescription, but may be preferred as they last longer, and therefore need applying less often.

Antihistamine eye drops such as Optilast (which contains olopatadine), or Azelast (which contains azelastine) only need to be applied twice daily. Targeted antihistamine products can be prescribed for those aged 6 and over. 

Olopatadine and azelastine are both antihistamine eye drops commonly prescribed to alleviate symptoms of allergic conjunctivitis, such as itching, redness, and tearing of the eyes. 

Olopatadine acts as both an antihistamine and mast cell stabiliser, preventing the release of histamine and other allergic mediators. It is available over-the-counter and by prescription, with varying concentrations of the active ingredient. 

Azelastine, on the other hand, is an antihistamine with additional anti-inflammatory properties, blocking histamine receptors and reducing the release of inflammatory mediators. Azelastine eye drops are typically available only by prescription. Both medications are effective in providing rapid relief, with noticeable effects within minutes after application. Common side effects for both may include temporary stinging or burning, while serious side effects are rare.