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Preservatives
in ophthalmic drugs and lubricants

Please see also Preservatives Reference List for a list of preservative concentrations in common prescription and over-the-counter eyedrops.
 

DISCLAIMER

This article is - like so much of this website - just my personal opinions and views. I am not a medical professional and have no medical training. Always consult your doctor about any drugs (Rx or OTC) or nutritional supplements you use.

 
IN BRIEF

For any eyedrops that you expect to use on a regular basis - whether it's a prescription medication or an over-the-counter lubricant - people with dry eye must exercise caution about preservatives. This is a case where what you don't know might hurt you, so it pays to do your homework.

If you feel that a preserved product you are using (or are considering) has a preservative that might be too toxic for regular use, please consider one of these options:

  • Look for a preservative-free version of the product. Many lubricants are available preservative free, and some prescription drugs are as well. Some drugs can be procured preservative-free through a compounding pharmacy.
  • Consult your doctor about alternative products for the condition you are being treated for. In some cases it may be worth seeking a second opinion.
 
is my eyedrop preserved? If so, with what?

Almost all eyedrops in a bottle are preserved. Check the label for specifics. Unpreserved products are usually packaged in unit doses, i.e. small tubes with twist-off tops meant to be used then discarded.

Here is a list of preservatives used commonly in over-the-counter eye lubricant products:

 
Preservative   Lubricants

Benzalkonium chloride (BAK)

 

BAK has been shunned by the best-selling eye lubricants because of the well documented risks from frequent exposure. However, the following tear products still use it:

B&L "Advanced Eye Relief" (Rejuvenation, Environmental)
Hypotears
Visine Tears
Murine Tears
Akwa Tears

 
Polixetonium   FreshKote, Dwelle, Dakrina, NutraTear
 
Polyhexamethylene Biguanide   Soothe XP
 
Polyquad   Systane, Tears Naturale II, Tears Naturale Forte
     
Purite   Refresh Tears, Refresh Liquigel, Optive
 
Sodium perborate (called GenAqua by Novartis)  

Genteal "Mild"
Genteal "Moderate"
Genteal "Severe" (gel)

TheraTears

     
 
are some preservatives safer than others?

Of course.

Benzalkonium chloride (BAK or BAC) generally has the reputation as one of the most toxic of the current widely used preservatives and there are reams of literature about how bad it is. (If you're wondering why it's still used, it's because it's highly effective as a preservative. The problem is that it's just as good at killing corneal cells as it is at killing bugs.)

With some of the "milder" preservatives, there have been some individual studies and a few studies comparing relative safety profiles. I'll be adding to this page when I get more references handy. Suffice to say for the moment that when you read a study showing which preservative is safest, please check the fine print to see which manufacturer funded the study.

Let's not throw babies out with bathwater though.

All preservatives are not BAK.

Most preservatives on which there are studies show some adverse effects in some degree; and it stands to reason - preservatives are made to kill stuff. But like with all medical treatment decisions, adverse effects of individual preservatives have their gradations and need to be weighed against the benefits of the drug containing them. Don't forget, either, that preservatives are put there for a reason. Speaking of which...

WHY ARE PRESERVATIVES USED AT ALL?

Or: Why aren't all eyedrops sold in preservative free versions?

This is a multiple choice question. Decide for yourself whether any or all are plausible explanations.

  • (medical) Preservatives keep eye drugs safe for everyday use. They kill bugs, making it hard for the drops to become contaminated in such a degree that they could cause your eyes serious harm.
  • (practical) The unpreserved unit dose alternative is expensive; many people - particularly the elderly, who also happen to be the greatest consumers of ocular drugs, cannot afford them, and (in the case of prescription drugs) may not be covered by insurers. They can also be more difficult to use than other packaging. Doctors, whose prescribing practices are often directly driven by patient compliance issues, are keenly aware of these kinds of constraints and typically prescribe what they think their patient is more likely to comply with. As a result, there has not been a lot of demand from the medical community for unpreserved drops.
  • (financial) Damage to the cornea from toxic preservatives leaves patients even more dependent on drugs, generating more revenue for the megapharmas. For example, BAK-preserved glaucoma drugs, which have to be taken daily, damage the corneas, increasing requirements for artificial tears or other drugs to treat the dryness.

Thankfully, there is at last growing recognition in the ophthalmic community that consumers must be provided with safer alternatives that do not expose them to highly toxic products on a long term basis. I hope this trend continues and that we see better, safer preservatives on the market as well as, ultimately, preservative free versions of all products for regular use.

 
shOULD i avoid ALL PRESERVATIVES?

That's a very simple approach, and happily for many people it is possible, practical and safe.

There are however many situations for people with eye conditions where this is simply not practical.

With prescription drugs, preservatives cannot be avoided when:

  • a preservative free version is not available;
  • an equally effective alternative without preservatives is not available; and
  • the benefits of the drug outweigh the potential risks of the preservative (e.g. glaucoma medications).

With over-the-counter lubricants the situation is more complex and typically involves more consumer choice - as well as tough dilemmas.

Some doctors tell their patients to use no preserved tears, which makes their choices simpler. Even doctors who have no problem with certain preservatives will often tell their patients to stick with a no-preservatives rule rather than risk confusing matters by attempting to distinguish between preservatives.

Some doctors leave the choice up to the patient and simply tell them which preservatives to avoid. In those cases, patients generally choose based on performance, availability, and cost.

If you're shopping for lubricants, and can afford it, by all means start with the preservative free ones. If you get sufficient relief with preservative free lubricants that your doctor approves, then you don't even have to bother thinking about the preservative issue. Happy happy happy.

For those who do NOT get sufficient relief of dry eye symptoms with unpreserved lubricants - and, let's face it, there is not exactly a huge selection to choose from - you may need to review whether there are additional dry eye treatments you need to explore, such as punctal occlusion or treatments for meibomian gland dysfunction. Another useful step is exploring things like eyewear to reduce symptoms (for example, moisture chamber eyewear, sleep masks, etc).

Sadly... if you got this far on the website, you've probably gone through a lot of different treatments and tear brands and none of this has been enough. So, you may be one of the many who can benefit from some kind of preserved lubricant. In this case, the benefits of a lubricant that gives a reasonable amount of relief for a reasonable amount of time and provides sufficient protection against erosions may well outweigh the theoretical risk from a mild preservative (assuming of course you tolerate it well in practice). In my personal case, I have been using certain preserved tears for many, many years, along with many other severe dry eye patients for more than a decade. I have become comfortable with the specific preservative based on its track record and its performance in my individual case.

Do your homework, weigh the risks and benefits, talk it over with your doctor, and make decisions you're comfortable with.

 
HOW DO I USE preserved drops SAFELY?

1. Don't overdose.

The rule of thumb many doctors use is, try to limit dosing to 4x a day if there is a preservative in the drop.

2. Be observant.

Artificial tears cannot simply be judged by how they feel the moment they hit your eye. Observe how frequently you need the drops, and how your eyes feel a few hours after putting them in. Watch for longer-term trends. A diary may help.

3. Get examined regularly.

Make sure you are under the regular care of an eye doctor and get basic exams like Schirmer and TBUT at regular intervals if possible. Even if the exam results do not seem to directly correlate to how you feel (let's face it, dry eye symptoms rarely correlate well with clinical exams - one of the reasons why it's so hard for dry eye drugs to get approved) they still are important for establishing benchmarks and identifying progress - or regression.

 
 
 

Do you have more information, links or references? Please email us.

Want to see what others have to say about this topic? Visit Dry Eye Talk, our community forums.

LAST UPDATED 3/07 by Rebecca Petris


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