Inanda Veterinary Hospital & Specialist Referrals Waterfall, Durban, South Africa
The veterinary nurse/technician should recognise the risks of chronic exposure to chemotherapeutic agents, and understand the value of preventative measures, rather than just performing them by rote. He/she should also know how to store, prepare for administration, and safely dispose of the different agents.
Introduction: Safe Handling of Cytotoxic Drugs
Many cytotoxic drugs are carcinogenic and mutagenic, some are teratogenic (> 50% increases in DNA breakages have been demonstrated in oncology ward sisters and oncopharmacists, although these results are disputed by some). Such support staff also have a higher chance of miscarriage. Some drugs are also extremely irritating and produce harmful local effects after direct contact with the skin or eyes. Persons handling and administering these agents should be aware of the potential dangers and take steps to minimize any risk to themselves, their staff, and their clients. Detailed local rules and working practices should be established in practices where cytotoxic drugs are used.
Cytotoxic drugs are commonly available in two forms:
Tablets or capsules for oral administration
Powder or solutions for injection
Tablets should never be broken or crushed and capsules should not be opened. This rule is broken too often by veterinary surgeons and could lay you open to very serious legal challenge.
Should a small patient require a small amount of a given tablet medication, options are:
Use an injectable form (e.g., cyclophosphamide)
Use an alternative (e.g., chlorambucil for cyclophosphamide)
Cyclophosphamide 50-mg tabs every other day cat may require only 12.5 mg give 1 tablet of 50 mg every 8–9 days instead (i.e., change frequency of dosing)
Contact an oncological pharmacist and request reformulation (at a charge). Ordinary pharmacists do not have the facilities or experience to carry out such reformulations safely, and may (should?) refuse.
Disposable latex gloves should be worn when handling any tablet, which does not have an inert barrier coat. Only non-powdered gloves should be used - and then double-gloved above, and beneath the cuff of a long-sleeved, impermeable gown specifically used for formulating chemotherapy. Powder aids absorption of spilled chemotherapy agents, and then aid retention against and adsorption through skin on the inside of the glove.
Where tablets are provided in individual wrappers, they should always be dispensed in this form.
In addition to the statutory requirements for the labeling of medicinal products, all containers used for dispensing cytotoxic drugs must be childproof and carry a clear warning to keep out of the reach of children. Containers should be clearly labelled with the name of the agent. This means that pill packets may not be used to dispense these drugs!
Staff and owners should receive clear instructions on the administration of tablets.
Disposable gloves should be worn when administering these tablets because the protective barrier may break down on contact with saliva.
Always wash hands following handling of any drug, even if gloves are worn and remain intact.
Excess or unwanted drugs should be disposed of by high temperature incineration by a licensed authority.
Wear long-sleeves jackets (isolation gowns work well), masks with filters, and splash-proof safety goggles; the company Uvex makes a variety of very good products such that you can find something comfortable for all staff.
Only the largest practices have laminar flow cabinets but these are desirable.
The main risk of exposure arises during the preparation and administration of injectable cytotoxics, many of which are presented as freeze-dried material or powder, requiring reconstitution with a diluent.
Potential dangers are:
The creation of aerosols during preparation/reconstitution of the solution
Protective clothing should be worn during reconstitution, administration, and disposal of these agents. The level of protection required varies according to the agent. The minimum requirement should be (also see above):
A gown with long sleeves to protect the skin
A protective visor or goggles to protect the eyes
A surgical mask to provide some protection against splashes to the face
The drug should only be reconstituted by trained personnel.
Reconstitution of the drug should only be performed in a designated area, free from drafts, and well away from thoroughfares and food.
If drugs such as doxorubicin are used on a regular basis, they should be reconstituted in a protective, vertical-flow, biologic safety cabinet.
Careful technique should prevent high pressure being generated within the vials and minimize the risk of creating aerosols.
If it is necessary to expel excess air from a filled syringe, it should be exhausted into an absorbent pad (disposed of in an appropriate manner - see below) and not straight into the atmosphere.
Luer lock fittings should be used in preference to push connections on syringes, tubing and giving sets.
All animal patients must be adequately restrained by trained staff (who should also wear protective clothing). Fractious or lively animals may need to be sedated. We sometimes tranquilise patients with midazolam-buprenorphine.
In the Event of Spillage the Following Actions Should Be Taken
The spilt material should be mopped up with disposable absorbent towels (these should be damp if the spilt material is in powder form). The towels should be disposed of as detailed below.
Contaminated surface should be washed with plenty of water.
Adequate care and preparation should be taken for the disposal of items (syringes, needles, etc.) used to reconstitute and administer cytotoxic drugs.
"Sharps" should be placed in an impenetrable container specified for the purpose and sent for incineration.
Solid waste (e.g., contaminated equipment, absorbent paper, etc.) should be placed in double-sealed polythene bags and disposed of by high-temperature chemical incineration by a licensed authority.
References are available upon request.