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Reducing Cytotoxic Drug Exposure in Healthcare: Determinants Influencing Cleaning Effectiveness
RS2006-DG03
Final Report Date: March 2008
| Principal Investigators: | Prescillia Chua (Fraser Health) & Winnie Chu (University of British Columbia - SOEH) |
| Co-investigators: | Chun-Yip Hon (UBC), Quinn Danyluk (Fraser Health), George Astrakianakis (OHSAH) |
For more information about this project, please contact Prescillia Chua.
Issue
Many cytotoxic drugs used to treat cancer and other diseases are known to be carcinogenic or mutagenic. Health care workers who handle these drugs may be at risk of developing adverse health effects such as organ toxicities, reproductive problems, tumours, and cancer. Although several guidelines for cytotoxic drug handling exist, studies have shown that contamination can occur even when proper engineering controls are in place. Using laboratory research methods, this project examined the effectiveness of the cleaning agents used to clean surfaces contaminated with the three cytotoxic drugs most commonly used in B.C. health authorities.
Key findings
- Currently used cleaning agents such as CaviCide®, Phenokil ™, chlorohexidine and bleach were tested against the three cytotoxic drugs most commonly used in B.C. (cyclophosphamide, methotrexate and 5-fluorouracil).
- None of the cleaning agents completely eliminated cytotoxic drug contamination on stainless steel surfaces, with or without additional isopropanol wash.
- When 70% isopropanol was applied after the application of the cleaning agents, the amount of cytotoxic drug residue was reduced but not eliminated.
- Deionized water did not clean cytotoxic drugs effectively, with or without the aid of isopropanol.
- Based on the findings, the research team recommends efforts to find more effective cleaning agents, more stringent compliance with personal protective equipment protocols, and updated education and training policies regarding healthcare workers who handle cytotoxic drugs at all stages or come into contact with contaminated surfaces.
Objectives
- To determine the effectiveness of cleaning agents currently used in B.C. health authorities
- To assess cleaning determinants, such as volume of cleaning agent and application method of cleaning agent
Method
The three most commonly used cytotoxic drugs in British Columbia health authorities were identified and selected for this study. These drugs, and their classifications according to the International Agency for Research on Cancer (IARC) are as follows:
- cyclophosphamide (CP) (Group 1 carcinogenic substance)
- methotrexate (MTX) (Group 3 carcinogenic substance)
- 5-fluorouracil (5-FU) (Group 3 carcinogenic substances)
The cleaning agents tested included: CaviCide®, chlorohexidine, Phenokil™, bleach and deionized water.
In a controlled laboratory environment, low, medium, and high concentrations of each of the cytotoxic drugs were applied to stainless steel sheets. These sheets are similar in quality to the working surfaces in pharmacy biological safety cabinets.
The sheets were cleaned using one of the cleaning agents with varied cleaning methods and volumes. The effect of additional cleaning with 70% isopropanol was also tested.
After each cleaning step, wipe samples were taken. The samples were analyzed for the presence of cytotoxic drug residuals, using a method called high performance liquid chromatography- tandem mass spectrometry (LC/MS/MS). This procedure was conducted at a research facility at the University of British Columbia’s School of Environmental Health.
Results
- Measurable amounts of MTX, CP, and 5-FU drug residue remained on the surfaces of the stainless steel plates when cleaned with any of the tested cleaning agents.
- Although none of the tested cleaning agents completely eliminated cytotoxic drugs, they all reduced the level of contamination on the test surfaces to some degree.
- Additional washing with isopropanol often further reduced the amount of drugs left on the surface.
- The drug residual amount was not affected by the cleaning method, i.e., whether the cleaning agent was poured directly onto the surface or onto a cleaning wipe.
- Inconsistencies were observed between triplicate samples of each cleaning agent. This may have resulted from differing amounts of pressure being applied during cleaning, such that higher pressure resulted in a cleaner surface, or that drug residues were absorbed onto gloves while performing cleaning and sampling.
Conclusions
None of the cleaning agents completely eliminated cytotoxic drugs, with or without additional isopropanol wash.
Although the number of experimental conditions tested was limited due to the scope of the project, the findings suggest that none of the currently employed cleaning agents would eliminate the three tested drugs completely. The findings also suggest that workers currently may have a false sense of security arising from the belief that current cleaning practices are sufficient.
Researcher recommendations
Based on the findings, the research team concludes that there is an urgent need for:
- More effective cleaning agents in order to reduce exposure to these hazardous drugs
- More stringent compliance with personal protective equipment protocols, particularly gloves and gowns
- Updated education and training policies regarding healthcare workers who handle cytotoxic drugs at all stages (from preparation to delivery), include nurses, pharmacy technicians, pharmacists, physicians, cleaning staff; and any other workers who may be in contact with contaminated surfaces
Future directions
Further research on this subject should also employ the same systematically controlled laboratory processes to evaluate cleaning effectiveness on all work surfaces. These surfaces include flooring, counter tops, handles, and instruments, all of which have typically been found with cytotoxic drug contamination.
Publications and conference presentations
UW/UBC 19th Annual Occupational and Environmental Health Conference, Semiahmoo Washington. January 8, 2007.
Presentation at the UBC School of Environmental Health: Weekly Seminar Series - Spring 2007.
BC Health Authorities Conference: Workplace Health, Safety and Wellness Conference, September 17 – 18, 2007. Kelowna.