Is the Requiem for Glutaraldehyde Now Playing?
Glutaraldehyde is a dialdehyde that is widely used as a high level disinfectant in healthcare. Glutaraldehyde has several occupational health issues including irritation, sensitization and occupational asthma. These issues encouraged manufacturers to develop new products in two directions, equipment and chemicals.
In the past medical items to be disinfected were soaked in an open bath containing a solution of glutaraldehyde. No more! Now high level disinfection with glutaraldehyde is almost exclusively performed in automatic endoscope reprocessors (AERs) that draw the somewhat acidic glutaraldehdye from the container, dilute and activate (raise pH to 7.5 to 8.5) to the required concentrations, disinfect the articles inside and rise them. These new machines have greatly decreased occupational exposure to glutaraldehyde.
New chemicals have been introduced such as peracetic acid, a strong oxidant and very efficient biocide that is used in several brands of AER. Peracetic acid is an irritant to the skin, eyes and respiratory system (ACGIH STEL TLV of 0.4 ppm), but to date there no indication of sensitization as with the aldehydes.
The other chemical that is widely offered as a replacement for glutaraldehyde is o-phthalaldehyde (OPA), another dialdehyde. OPA has a lower vapor pressure than glutaraldehyde and so much less odor and being more active is used at a lower concentration However, OPA has also been found to cause sensitization and occupational asthma like its dialdehyde sibling glutaraldehyde.
Even though glutaraldehyde is still widely used in the US and many other countries, its star has fallen in some places. For example glutaraldehyde is no longer used in the UK’s National Health Service because of a combination of employee health effects and efficacy concerns. The latter were because glutaraldehyde is a fixative (cross links proteins) and so may even hinder disinfection of microbes remaining on improperly cleaned devices with heavy soil. There is pressure to withdraw glutaraldehyde as a high level disinfectant in Australia as well.
Here in the US, Advanced Sterilization Products has withdrawn its flagship glutaraldehyde product, Cidexplus, from the market as of January 1st this year; saying “ASP is supporting the industry choice to use glutaraldehyde-free solutions in disinfecting and sterilizing endoscopes” and recommending that users switch to their Cidex OPA product instead. There are still many brands of glutaraldehyde HLD registered by the FDA and for sale such as Metrex’s metricide plus 30; so the requiem for glutaraldehyde may not be playing yet, but it looks like the orchestra is warming up.