Definition of cytotoxic drugs

Cytotoxics should refer to chemotherapy drugs antineoplastic drugs have been in clinical use for decades and are of great importance in the treatment of cancer and certain other diseases Cytotoxic drugs are chemicals that affect cell growth and proliferation most of which either bind directly to genetic material in the cell nucleus or affect cellular protein synthesis Typically cytotoxic drugs do not distinguish between normal and cancerous cells Cytotoxic drugs are often administered to immunocompromised patients and as most of these drugs are myelosuppressive this may place patient at high risk of developing severe infections For this reason when parenteral cytotoxics are prepared aseptic procedures must be strictly adhered to in order to prevent microbial contamination In addition as most of these agents have a narrow therapeutic index the accuracy of the preparation must be assured Pharmacy departments should have rigid checking procedure in place In terms of occupational exposure a hazardous drug is defined as an agent that due to its inherent toxicity presents a danger to healthcare professional These drugs are identified based on one or more of the four following characteristics they are carcinogenic genotoxic teratogenic or toxic at low doses in animal model or treated patients Hazardous drugs include antineoplastic and cytotoxic agents some hormonal agents immunosuppressants antiviral medications and some monoclonal antibodies A list of hazardous drugs that require special handling should be posted in every facility at all relevant working places that provide drug preparation and administration services Studies carried out by Falck et al In the 1970’s indicated that unprotected nurse who worked in environment in which hazardous drugs were prepared and administered had higher level of mutagenic substances in their urine as compared to non-exposed workers This study suggested that nursing personnel were being occupationally exposed to cytotoxic drugs many of which are mutagenic This study was confirmed by numerous studiesexamining urine mutagenicity chromosomal aberrations sister chromatid exchanges and other endpoints in pharmacists and nurses who handle cytotoxic drugs.

A review of 14 studies described an association between exposure to antineoplastic drugs and adverse reproductive effects 9 studies showed some positive association The most common reproductive effects found in these studies were increased fetal loss congenital malformations low birth weight and congenital abnormalities and infertility Occupational exposure to hazardous drugs and the potential health risk to healthcare workers first become a recognized safety concern in the 1970s

Sources of exposure of health care providers to cytotoxic drugs are varied and routes of exposure are typically inhalation dermal or oral One route of exposure is inhalation via droplets particulates and vapours Many procedures can result in aerosol generation For example drug injection into an IV line removal of air from the syringe or infusion line and leakage at the tubing syringe or stopcock connection clipping used needles and crushing used syringes Drug particles can become airborne after drying of contaminated areas Dermal contamination can arise from cytotoxic drug contamination on the outside of vials Thus the environment of operator may be contaminated even before cytotoxic reconstitution has begun Researchers have detected measurable air level of cytotoxic drugs inside and outside biological safety cabinets from wipe samples of cytotoxic drugs on surfaces of workstation and at points distant from places of preparation and administration of drugs Inadvertent ingestion is also problematical When food or beverages are prepared stored and consumed in work areas they may easily become contaminated with airborne particle of cytotoxic drugs Greatest risk is direct skin contact with the drug in the event of a spill or leakage Exposure is possible throughout the medication circuit in the hospital or at home The medication circuit includes all of the steps through which the drug travels from the receiving dock to the storage facility as well as its preparation administration elimination in the excreta and in its wastes A number of individuals may be exposed throughout this circuit for example the receiving and transport workers pharmacists and pharmacy technicians the physicians nurses and inhalation therapists who administer the drugs the nurses and patient service associates involved in patient care following the administration of hazardous drugs the hygiene and sanitation workers the waste management workers the laundry workers etc To provide workers with the greatest protection employers should number one implement necessary administrative and engineering controls and second assure that workers use sound procedures for handling hazardous drugs In addition employees by their work practices influence their own occupational exposure and that of those around them Employees can help minimize their potential exposure to these agents by number one staying current on the knowledge of the occupational risk posed by these agents and number two ensuring that their work practices follow the best current recommendations It is very common in the setting of standards for industrial hygiene to include an obligation to follow a hierarchical order of level of protection for employees at their workplace It is imperative that the sequence of protection levels starts with level 1 and ends at level 4 In other words one is not free to choose the measures in protection to exposure of cytotoxic drugs The level of protection measures are in descending order of importance Level 1 the most important Elimination substitution replacement We can change the product to another product which is non-toxic or less toxic But currently this is rarely possible in the treatment of cancer patients but this level could become very important as more targeted therapy become available Level 2 Isolation of the hazardous source containment we could contain the toxic product in its container or at source By containing the product at its source the contamination of persons or materials is prevented If possible source containment should be continuous throughout the entire process of production and administration of the product Level 3 Engineering controls and ventilation We could apply local and general ventilation or extraction in order to dilute the toxic product Biological safety cabinets and isolators should be considered as level 3 measures Level 3 B administrative controls and organization measures We could organize the work in such a way that the duration of exposure is reduced Or we could organize the work in such a way that the number of employees exposed is reduced.

If levels 1 2 3 are impossible or insufficient then the next level is applied Level 4 Personal protective equipment Individual protection by using personal tools For example gloves masks gowns goggles or face shields and other equipment They could create a temporary barrier between the contamination and operator And Remember it is important to use proven resistant material tested for these specific products and conditions Terminology such as cytotoxic glove is not sufficient to ensure adequate protection unless accompanied by test results