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Eye drops - all you need to know.

Chlorsig / Chloramphenicol

Chlorsig eye drops or eye ointment are the most popular forms of chloramphenicol.

By Published On: 26 October 20204.4 min read

Chlorsig or Chloramphenicol is a broad spectrum antibiotic. Chlorsig is used to treat a range of eye infections, including for stye. It is available in the form of eye drops and ointment. Unfortunately it is grossly overused. This has only become worse since it became available over the counter.

Bacterial infections do not cause most eye irritations.  Allergy, dryness or viral eye infections cause most conjunctivitis.  None of these causes will respond to this medication.

When is Chlorsig indicated?

If you are diagnosed with a bacterial eye infection unrelated to contact lens wear, this medication is a good choice. Why? Because it’s effective against a broad range of bacteria. It is also a good choice if you have a scratch on your eye that needs to be protected from infection. This is called prophylactic use. It’s also used after eye operations to protect the eye from harmful pathogens. Chlorsig for stye can also be useful (see below).

Chlorsig eye drops or ointment?

If the eye has been scratched, e.g. by a branch or a baby’s fingernail, your optometrist may prescribe Chlorsig ointment (rather than drops). Ointment is also an excellent lubricant.  It will prevent your eyelid from sticking to the surface of your eye while you sleep. Chlorsig will also protect the eye against any bacterial infection, including for stye.

When are these eye drops and ointment NOT indicated?

If you don’t have a bacterial infection in your eye, then Chlorsig will not help. Chances are, even if you have an eye infection, it may have a viral (or fungal) cause. Most irritations are not infections at all, and are as a result of inflammation. This may be autoimmune (e.g acute inflammation like uveitis). Or it may be an allergic reaction to pollen or grasses. Dry Eyes also cause redness and inflammation and will not respond to this type of eye drop. In fact, these eye drops are preserved, and this preservative makes the irritation and inflammation worse.

If you have DRY, IRRITATED eyes, download our free eBook for more information on the most successful treatment.

Side effects: Aplastic anaemia risk

Chloramphenicol is the active ingredient used in Chlorsig eye drops and eye ointment. This drug is also taken orally or injected for serious bacterial infections, when others have failed. In the USA, Chlorsig eye drops are NOT prescribed. Why not? Because the active ingredient can rarely cause a serious systemic condition. This is called aplastic anaemia and is very rare. But the studies show that it is the high-dose oral form of the drug that can cause this disease. In Chlorsig eye drops, the active ingredient is very dilute.

It is considered harmless by hundreds of thousands of doctors in other countries including Australia and the UK.

If these eye drops did cause aplastic anaemia, we would expect to see a lot more of this disease in Australia and the UK, where it is used a lot. This is NOT the case. In fact, there is no difference in the incidence of aplastic anaemia between Australia and the USA. This is even though at least 5 million bottles of these eye drops are sold every year.

Now the most important point!!

Chlorsig eye drops and ointment should not be used as a treatment for any contact lens-related red eyes. Ever! A nasty bacteria called pseudomonas causes 70% of these infections. (See contact lens-related pseudomonas keratitis). This eye condition does not respond to these eye drops or ointments. There are cases of eyes going blind because of inappropriate use of this drug when contact lenses are involved.

Chlorsig over the counter: how to avoid unnecessary use

Avoid using over-the-counter Chlorsig unless you have been specifically advised to get it by your therapeutically-qualified optometrist or ophthalmologist.

If you have a red, irritated, inflamed eye, try to see an eye care practitioner rather than a GP. Optometrists and ophthalmologists have special equipment to examine your eyes under high magnification and strong light. These are called slit-Lamp bio-microscopes. They can observe classic signs that help them decide what’s causing the problem. Is it a bacterial infection? Or a stye? Maybe it’s another, non-bacterial infection (such as a virus)? Or a non-infective cause?

Chlorsig for stye

We’ve written about stye on another page. Chlorsig ointment for stye won’t make it go away, but it doesn’t do any harm.  It can even be beneficial. – If the stye breaks it can release pus onto the surface of the eye. Chlorsig can help prevent possible bacterial conjunctivitis.chlorsig-for-stye


95% of red eyes are not bacterial conjunctivitis. Red eyes have many other causes. Chlorsig is RARELY indicated for a red eye in an adult.

Interestingly, children are much more likely to have bacterial infection of the eyes. This is due to an undeveloped immune system. It is thus more likely that Chlorsig is indicated in the younger population.

Where possible, choose an optometrist who is therapeutically qualified. Not only will they have had in-depth training in distinguishing between different eye diseases, but they will also be able to prescribe the appropriate eye drops to treat your eyes.

Worried about your eyes? Give us a call on (02) 9290 1899.  Or book an appointment with one of our therapeutically qualified optometrists.


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