ABSTRACT: It is common for veterinary professionals to forget about potential dangers and risks that arise from medications whilst in the work place. Cytotoxic drugs are one of the groups of medicines that give rise to concern.

Cytotoxic drugs – also known as antineoplastic drugs or chemotherapy drugs – are now commonly used in everyday practice. If these drugs are used without full knowledge and understanding of the potential hazards to personnel, then this can lead to increased exposure. Studies conducted in human hospital workers have shown the presence of drugs in their bodily fluids and its association with reproductive problems and leukaemia.

Cytotoxic drugs are commonly administered by injection – intravenously (iv), intramuscularly (im) or subcutaneously (sc) – and by mouth in the form of a tablet. These drugs range from Vincristine, Vinblastine, Doxorubicin, Epirubicin and Carboplatin which are all forms of intravenous chemotherapies, and cyclophosphamide and leukeran which are oral forms of chemotherapy. These are just a few examples of the drugs available and not all are commonly used in practice.

Many cytotoxic drugs are known as carcinogenics (cancer promoting) and genotoxins (damages cellular DNA, resulting in mutations or cancer) and can be extremely irritant and cause harmful local effects after direct contact with the skin or eyes. Cytotoxic drugs are toxic to cells they are targeted at. They prevent the cells from dividing and thus growing. As they act on cells, they are also able to affect normal cells, which can result in undesirable effects. Precautions need to be taken within practice to protect all personnel who come into contact with either the drugs or patients receiving the drugs.

Safe handling

The risk of exposure to chemotherapy drugs is greatest during handling, preparation and administration of the drug. Exposure is possible via three routes: inhalation, direct contact and direct entry into the body – by ingestion or self-injection (needle stick injury), for instance. Other routes of exposure include handling chemotherapy waste (syringes, gloves, empty bottles, catheters) and contact with secretions (vomit, saliva, urine and faeces) from treated patients.

Procedures should be in place to minimise and prevent exposure via these sources. Firstly, personnel at most risk should be removed from the equation.

As with many medications, chemotherapy drugs can have possible reproduction risks. Therefore, those personnel who may be pregnant, or trying to become pregnant, should be excluded from the use and handling of chemotherapeutics and those patients receiving the medication.

Those personnel who are to come into contact with chemotherapy and patients receiving the medication should abide by strict guidelines set by the practice. The long-term occupational effects of these agents are unknown; therefore guidelines set out should help to measure and prevent contamination to personnel.

The preparation of chemotherapy should be done by trained personnel. All chemotherapy doses should be checked by two staff members, as well as checked against doses previously received, if any. These drugs should be prepared inside a microbiological safety cabinet with the use of absorbable mats and spirit soaked swabs to cover needle insertion points reducing any aerosolisation (Figure 1).

Figure 1: Ideally all chemotherapy drugs should be prepared in a microbiological safety cabinet. There are products on the market if a safety cabinet is not available

If a safety cabinet is not available, then use PhaSeal. This is a closed system drug transfer device that mechanically prohibits the escape of hazardous drug aerosols or vapours into the environment.

Wearing gloves is sufficient when handling the tablet forms of chemotherapy, but it is advised to wear gowns, gloves and protective head gear when preparing the liquid cytotoxic drugs, in case of spillage. Gloves should always be worn over the gown sleeves to help minimise contamination to personnel.

It is good practice to have a designated area for the safe preparation and administration of cytotoxic drugs. This may not always be practical, particularly in smaller practices with limited space, so guidelines should be set into place to ensure staff know when cytotoxics are about to be administered, where, and that the area has been thoroughly cleaned after administration to prevent contamination. Staff should be given appropriate training to ensure they are fully aware and understand the hazards of dealing with these medications.

Safe administration

The administration of chemotherapy is most commonly by intravenous injection and an IV catheter should be placed and secured. Many of these drugs are vesicants and can, therefore, cause extensive tissue necrosis if accidentally given perivascularly (extravasation). This can result in the patient requiring surgical reconstruction or even limb amputation.

The placement of an IV catheter should be perfect at the first attempt and repeated placement attempts should be avoided. Only competent, trained personnel should place them in order to avoid this; and if the patient is receiving regular doses of chemotherapy, then the limbs should be alternated for the catheter placement. Before the drug is administered, the IV catheter should be thoroughly flushed with saline only, to ensure it is correctly in the vein, and then flushed again after administration to ensure no traces of the drug remains within the catheter (Figure 2).

Figure 2: All catheters should be thoroughly flushed with saline only, before and after chemo administration

It has been reported that Doxorubicin is incompatible with heparin and a precipitate may form, so it is good practice to only use saline to flush IV catheters for all chemotherapy administration. Once the drug has been administered and flushed through, the IV catheter should be removed immediately.

If you are administering cytotoxics, it is best that you are equipped with a cytotoxic spill kit. Each spill kit contains all equipment and advice required to effectively clean any cytotoxic spillage. During preparation, administration and dealing with spillage of chemotherapy, the use of personal protective equipment (PPE) should always be employed.

Cytotoxic non-absorbent gowns, thick nitrile powder-free gloves and protective facial wear, such as goggles or screens, should always be worn during preparation and administration of cytotoxic drugs (Figure 3). It must be ensured that the gowns used are non-absorbent. Although these items of protective equipment will not provide 100 per cent protection, good guidelines for the safe handling and administration will help to eliminate unwanted contamination.

Figure 3: When administering chemotherapy, gloves, gowns and protective head gear should always be worn

Safe waste disposal

Once cytotoxics have been administered, waste must be disp
osed of correctly. The use of a disposable prep tray is a good way to keep all the equipment required for administration (swabs and syringes) together and, once finished, the whole tray – including the chemo waste (except needles) – can be placed into the clinical waste. It is always best to ‘double bag’ the waste, so the use of clear sealable bags for each chemotherapy patient and a separate waste bin for chemotherapy are advised.

Using Luer lock syringes ensures the needles are firmly on the syringe because they must be screwed on. Needles should not be recapped as this is a potential hazard for ‘needle stick’ injuries and it is best to dispose of the needles into a sharps bin whilst still attached to the syringe. A sharps bin with a purple lid should be used for the contaminated needles and syringes and should ideally be only used for cytotoxics (Figure 4).

Figure 4: Standard equipment for all chemotherapy rooms includes sharps and DOOP bins, thick nitrile gloves and non-absorbent gowns. All rooms should have a spill kit available

Normal clinical waste bags can be used for all other waste and should be changed every day and clearly labelled as cytotoxic waste. Protective clothing, such as gowns, should only be used once and then disposed into clinical waste. Areas used for the administration and preparation of cytotoxic drugs should be clutter free and thoroughly cleaned, including equipment, such as goggles.

When handling cytotoxic drugs, contaminated waste or patients receiving chemotherapy, gloves should always be worn. This again helps prevent contamination. The storage of cytotoxic drugs should be taken into consideration.

Some require refrigeration whilst others are to be at room temperature (Figure 5). They should all be securely locked away. Open bottles should be labelled with the date of opening and discarded one month after if not used. These can be discarded by sealing them into a bag and then placing them into a DOOP bin with a purple lid, similar to the sharp bin and only used for cytotoxic waste. The handling of all drugs – open or not – should be done whilst wearing gloves.

Figure 5: Some drugs must be refrigerated. These should be locked away and no food and drink permitted

When handling patients receiving chemotherapy, gloves should always be worn. It is good practice to ensure each patient’s kennel is clearly labelled with a ‘receiving chemotherapy’ sign and all personnel should be informed. This helps to maintain prevention of contamination within the practice and also notifies those most at risk – pregnant colleagues, for instance – to avoid contact with these patients.

All patients should be encouraged to toilet on grass and if concrete runs are used, appropriate PPE should be worn when cleaning areas. Faeces should be placed into a sealed bag and soiled bedding should be placed directly into a washing machine or placed into a sealed clinical waste bag until it can be washed separately from other bedding. Urine, blood and vomit should be completely absorbed using paper tissue before the area is cleaned. Patient feed bowls and litter trays should always be washed separately.

For those practices increasing their chemotherapy case load, consideration of implementing operating procedures for storage of chemotherapy drugs, protective clothing for personnel, preparation of the medication and waste of all chemotherapy exposed waste materials and drugs, drug spills and emergency procedures for contamination and spills, would help to prevent contamination.

Safe home

Once the patient has been discharged, the owner’s exposure to cytotoxics is likely to be very small and, therefore, they should not worry about this. However, it is advisable to inform owners of precautions they should take to maintain little or no exposure.

Owners should be advised to treat all of their pet’s bodily fluids as potentially harmful. The amount of drug excretion will vary significantly, although the body excretes more by-products during the first few days following treatment.

They should be provided with gloves to wear when dealing with accidents within the home. Solid waste and kitchen paper can be flushed down the toilet or bagged and put into domestic waste, and areas can be cleaned with household bleach once the waste has been cleared. Owners should discourage their pets from licking them, particularly children and the elderly.

As within practice, feed bowls and bedding should be washed separately and the pet should be encouraged to urinate on grass. If the patient is to go home with oral chemotherapy, the medication bottle should be clearly labelled as cytotoxic and the owner should be provided with gloves to wear for the administration.

Good guidelines and personnel training within practice will contribute to the prevention of contamination of cytotoxics. Practices increasing their chemotherapy work load should implement health and safety guidelines and procedures to ensure all veterinary personnel, patients and owners are not exposed.

Author

Jody Blyth Tancock RVN

Jody passed the National Diploma in Animal Care from the College of West Anglia in 2002, whilst working for a local quarantine kennels. She joined the Animal Health Trust (AHT) the same year, as a trainee VN, and gained her RCVS Veterinary Nursing Certificate in 2004. She continued to work at the AHT, firstly as a shift nurse – rotating through kennels, clinics and theatre – and then, in 2006, she took on the role of Oncology Nurse. She is an A1 assessor and is currently studying for the HE Diploma in Clinical Veterinary Nursing at the University of Central Lancashire, in conjunction with the RCVS Advanced Veterinary Nursing Diploma.

Useful references

HAYES, A. (2002) Safe use of anticancer chemotherapy in small animal practice. In Practice 27: 1 18-127.

DOBSON, J., DUNCAN, B. and LASCELLES, X. (2003) BSAVA Manual of Canine and Feline Oncology, 2nc edn. British Small Animal Veterinary Association. LaDOU, J. (2003) Current occupational anc environmental medicine, 3rd edn. McGraw-Hill Professional, pp. 227-228.

Further resources

Health & Safety Executive. Safe Handling of Cytotoxic

Drugs. HSE information sheet MISC615 

www.hse.gov.uk

PhaSeal transfer device

www.carmelpharma.com/phaseal.html

Biological safety cabinets

www.triplered.com/cabinets.html

Cytotoxic PPE. www.helepet.co.uk

Veterinary Nursing Journal • VOL 25 • No6 • June 2010 •