Occupational exposure to hazardous drugs and the resulting potential health risk to healthcare workers first became a recognized safety concern in the 1970s. Published data related to the issue of occupational exposure prompted the Occupational Safety and Health Administration (OSHA) to issue guidelines in 1986 for the handling of antineoplastic and other hazardous agents by healthcare personnel. These guidelines, which were updated and revised in 1995, are perhaps the most widely recognized and closely followed recommendations in U.S. healthcare facilities in which hazardous drugs are routinely prepared and administered. A number of other organizations have also published reports related to the safe handling of hazardous drugs, including the National Institutes of Health (NIH), the National Study Commission on Cytotoxic Exposure, and the American Medical Association’s (AMA) Council on Scientific Affairs.This article provides a brief review of the critical elements of safely handling hazardous drugs, and devices that can be used to improve compliance with safe handling procedures.
In terms of occupational exposure, a hazardous drug is defined as an agent that presents a danger to healthcare personnel due to its inherent toxicity. These drugs are identified based on one or more of the four following characteristics:
- They are carcinogenic (as reported by the International Agency for Research on Cancer)
- They are genotoxic
- They are teratogenic
- There is evidence of toxicity at low doses in animal models or treated patients
Hazardous drugs include antineoplastic and cytotoxic agents, immunosuppressants, and antiviral medications. A list of hazardous drugs that require special handling should be posted in every facility that provides drug preparation and administration services.
|Table 1: Examples of Hazardous Drugs*|
|* This list is not intended to be all-inclusive
** As identified by the following:
A – The National Institutes of Health, Clinical Center Nursing Department
B – International Agency for Research on Cancer
C – Celgene Corporation
Sources of Hazardous Drug Exposure
The inadvertent introduction of hazardous drugs into an environment can occur in various ways. Drug containers may become damaged in the shipping process. A broken, cracked, or otherwise damaged container may result in leakage of the hazardous materials onto other containers. If not properly inspected upon receipt, the shipping container can be opened in the receiving area, exposing receiving personnel to the hazardous agent. In addition, contamination of the surrounding drug storage areas may occur. The manipulation required to prepare hazardous drugs for administration may also lead to environmental contamination. Leaks, spills, and the creation of aerosols of liquid drugs can occur during dose preparation. The process of priming IV tubing may lead to inadvertent environmental contamination if the priming process is not performed appropriately. In addition, during drug administration, tubing and injection port connections that are not properly secured may lead to leakage of the prepared agent.
Inappropriate disposal of hazardous drugs, either from the clean-up of spills or leaks, or from waste created during drug preparation and administration, can also lead to environmental contamination.
Strict compliance with policies and procedures related to the storage, handling, preparation, and disposal of hazardous drugs will reduce the number of incidents of environmental contamination, as well as the risk of occupational exposure to these agents. However, a recent study conducted at six cancer treatment centers in the U.S. and Canada revealed substantial levels of contamination in pharmacy drug preparation areas and a drug administration area despite the fact that appropriate handling precautions were in place.
Early studies employed a variety of methods in an attempt to quantify worker exposure to hazardous drugs. Mutagenic changes in the urine and evidence of chromosome damage in healthcare personnel who have prepared or administered antineoplastic drugs led to the conclusion that handling such drugs poses a genuine health risk to the individuals involved. Because these measures were indirect, and a direct cause-and-effect relationship could not be determined, more direct methods of determining exposure have been developed. These methods include urinalysis to determine the presence of metabolites of dangerous drugs handled by healthcare workers, and environmental air and surface sampling techniques.
Impact of Hazardous Drug Exposure
Patients undergoing treatment with cytotoxic or hazardous drugs suffer a wide variety of side effects due to the drugs’ nonselective mechanisms of action. These side effects include diarrhea, nausea, vomiting, hair loss, and irritation of the skin and mucous membranes. In addition, secondary tumors have occurred in cancer patients treated with certain antineoplastic agents. The long-term impact of low-level exposure to these antineoplastic agents, however, is unknown. Some epidemiological studies suggest that spontaneous abortions and fetal malformations suffered by nurses who worked in environments in which hazardous drugs were prepared and administered may be related to occupational exposure to these agents. This evidence highlights the critical need to reduce the risk of exposure to hazardous drugs by those in the healthcare environment.
Suggested Safe Handling Methods
In general, there are three critical elements involved in the safe handling of hazardous drugs. They are personnel, equipment, and strict adherence to policies and procedures.
Personnel: Only authorized and adequately trained personnel should receive, prepare, transport, or administer hazardous drugs. A clearly defined orientation and training program should be completed by every employee who may come into contact with a hazardous drug container. Personnel must be made aware of the unique nature of these agents and the potential risks associated with exposure to them. All employees must be educated regarding the appropriate steps to take in the event of accidental exposure to a hazardous drug. Employees who are pregnant or breast-feeding should be reassigned to areas where contact with these drugs will be avoided.
A systematic method for evaluating and documenting employee performance as it relates to proper preparation techniques must be in place. Initial training, ongoing periodic written assessments, and observed demonstration of hazardous drug preparation techniques are necessary to verify employee competency. Many facilities evaluate personnel by simulating drug preparation using a fluorescent compound such as fluorescein. This allows the visualization of any spills or aerosols under UV light after the preparation process has been completed, allowing for an objective assessment of personnel technique.
Equipment: Class II contained vertical flow biohazard cabinets, or biological safety cabinets (BSC), are currently recommended for preparing hazardous drugs. This equipment provides a Class 100 clean-air workstation while affording some protection to personnel and the environment from exposure to the product being prepared. The specific type of BSC best suited to a particular facility will depend on the volume and types of products prepared, available space, cost, and other local requirements for handling and ventilation of hazardous materials. Currently, the minimum recommendations are a Class II, Type A biological safety cabinet. Whatever the model used, it should be certified according to specifications of the National Sanitation Foundation Standard 49 and Class 100 specifications of Federal Standard 209C. The cabinet must be certified upon installation, whenever moved or repaired, and at regular intervals of six months or less. Policies and procedures for routine cleaning and disinfection of BSCs should be developed.
These devices have an open front with inward airflow, which forms a protective barrier to prevent the escape of contaminants released during the drug preparation process. Interference with this barrier creates breaks in the effectiveness of the containment system. Therefore, the BSC must be placed in a location that prevents air currents from disrupting the protective barrier. Thorough operator training is also critical to the appropriate use of a BSC.
In addition to the use of BSCs, protective apparel and other supplies designed to minimize the risk of exposure to hazardous drugs must be utilized appropriately. All workers involved in the handling of hazardous drugs should wear powder-free, disposable gloves with reasonable thickness, good fit, and adequate tactile sensation. Some published guidelines recommend double-gloving.
A low-permeability, lint-free disposable protective gown with a closed front, long sleeves, and tight-fitting elastic or knit cuffs should be worn at all times when preparing hazardous drugs. This garment should not be worn out of the immediate drug preparation or administration area.
Proper techniques and supplies designed to aid in the safe preparation of hazardous drugs must be utilized at all times. Syringes and IV administration sets with Luer-lock type fittings should be used to prepare and administer hazardous drugs to reduce the potential for accidental leaks or separation of the fittings. The development of positive pressure in drug vials and syringes must be avoided to reduce the possibility of drug aerosols being introduced into the workspace. The use of venting devices with hydrophobic filters, when used appropriately, can provide an additional measure of safety during the drug preparation process.
Policies and Procedures: Specific policies and clearly defined procedures are critical in guiding personnel to appropriately handle hazardous drugs. Every employee who comes into contact with hazardous drugs or their containers must be educated regarding departmental policies and procedures, and be routinely evaluated for compliance with these important safety practices.
New Safety Devices
A closed system for the preparation, administration, and disposal of injectable hazardous drugs has recently been made available for general use. This system prevents the escape of drugs or drug aerosols into the environment using unique design features that create a fully sealed system that eliminates potential exposure to the drug being prepared. The PhaSeal system (Carmel Pharma) has three components; a protector, an injector, and a connector. Initial testing of this system demonstrated its effectiveness in reducing environmental contaminants resulting from the preparation and administration hazardous drugs. The system is considered easy to use, and has been shown to reduce the level of environmental contamination in areas in which these agents are prepared and administered. This system may be considered the first significant advance in reducing occupational exposure to hazardous drugs since the release of the 1986 OSHA guidelines.
Statistics have shown an increase in the number of people receiving chemotherapy. Current treatment regimens that include hazardous drugs are more complicated than those employed in the past. Many regimens include high-dose therapies and the use of multiple-drug combinations. While these newer therapies have significantly improved cancer survival rates, preparing more drugs and using higher doses of drugs will likely increase workers’ exposure to these hazardous drugs. Diligence in ensuring the safety of personnel who prepare and administer these drugs must be a high priority in facilities providing these services. Appropriate training, utilization of effective equipment and supplies, and strict compliance with detailed policies and procedures provide the best approach to reducing the potential health risks of occupational exposure to hazardous drugs.