Exocin

Exocin is a sterile eye drop solution containing ofloxacin 3 mg per ml, an antibiotic from the fluoroquinolone family. Ofloxacin blocks bacterial DNA gyrase, so the organisms can no longer copy their genetic material and stop multiplying. The UK SmPC lists it for external infections of the eye and its surrounding tissues, such as bacterial conjunctivitis and keratoconjunctivitis, caused by bacteria sensitive to ofloxacin. Viral conjunctivitis and allergic red eye will not respond to it, which is why an examination comes first.

Only one concentration is made, 0.3%, and it is offered here in multiples of 2, 4 or 6 bottles. In the UK the dropper bottle contains 5 ml. Once opened, a bottle should be thrown away after four weeks even if some solution is left, because the preservative cannot protect it indefinitely.

For adults and children the SmPC gives one or two drops into the affected eye every two to four hours while awake for the first two days, then four times a day. Treatment should not continue beyond ten days. Wash your hands, tilt the head back, pull the lower lid down gently and let the drop fall into the pocket without the nozzle touching the eye or lashes. Pressing lightly on the inner corner of the eye for a minute afterwards keeps more of the medicine where it is needed. When a second eye product is in use, leave several minutes between them. If the eye is no better after a few days, or gets worse, it needs to be looked at again. Each person should have their own bottle; sharing drops, towels or pillowcases makes it easy to pass an infection on, and anyone with a sticky eye is wise to wash their hands often and avoid rubbing it. Sudden pain, marked loss of vision or extreme sensitivity to light are not typical of simple conjunctivitis and call for same-day assessment, if necessary at A&E or an eye casualty unit.

Exocin is licensed by the MHRA and is a prescription-only medicine (POM); the brand has long been associated with Allergan, now part of AbbVie. Whether a fluoroquinolone drop is the right choice, rather than chloramphenicol, for example, is decided by the prescriber.

Do not use it if you have ever reacted to ofloxacin, another quinolone such as ciprofloxacin, or any ingredient in the drops. The solution contains benzalkonium chloride, which can irritate the eye and discolour soft lenses; contact lenses should not be worn while an eye infection is being treated. Long courses can allow resistant bacteria or fungi to take hold. Serious allergic reactions and, very rarely, tendon problems are known with fluoroquinolones taken by mouth, and although the amount reaching the bloodstream from eye drops is small, any rash, swelling or tendon pain needs prompt advice. In pregnancy and breastfeeding Exocin is used only if the expected benefit justifies it.

The most frequent complaint is short-lived stinging, irritation or discomfort when the drops go in. Less often people report watery or sore eyes, itching, sensitivity to light, swollen eyelids, a feeling of something in the eye or redness around it. Vision can blur briefly after each dose, so wait until it clears before driving. Dizziness and nausea are uncommon. Please report suspected side effects through the Yellow Card scheme.