Whilst all medications used in the treatment of cancer are high-risk medications there are certain cancer agents, routes of administration and populations that require even greater focus on the potential for medication misadventure to occur. In many cases, experience has been gained due to the occurrence of unfortunate adverse events.
This section highlights recommendations based on key published reports however the medications referred to in this section are not exhaustive. There are a number of cancer agents that are more prone to error due to nomenclature, formulation and route of administration (refer to practice points in this section).
Whilst any agents can potentially be administered by the incorrect route if appropriate safety steps are not followed, vinca alkaloids have been implicated in the majority of errors involving administration of incorrect therapeutic agents by the intrathecal route. Virtually all cases have resulted in death or permanent disability.
Separate requirements for these agents have been specified by the Australian Commission on Safety and Quality in Health Care.
Etoposide is available in both intravenous and oral formulations. The intravenous formulation comes in two variants: etoposide base and etoposide phosphate salt with 113.6mg of etoposide phosphate being equivalent to 100 mg of the etoposide base. Variances between the etoposide dose prescribed and that actually given have been reported due to misunderstanding of the differences in the formulation at the prescribing, ordering and dispensing stage.
All vinca alkaloids for administration to adult patients must be supplied in an infusion bag. The minimum recommended volume is 50 mL to be administered over 5–15 min. All vinca alkaloids for administration to paediatric patients over 10 years of age must be supplied in an infusion bag in a volume of 20–50 mL to be administered intravenously over 5–10 min. For patients younger than 10 years a risk assessment must be carried out to support any decision to use syringes instead of infusion bags.
Distinctive warning labels must be placed on all vinca alkaloids preparations, “FOR INTRAVENOUS USE ONLY. FATAL IF ADMINISTERED BY ANY OTHER ROUTE”.
All etoposide phosphate preparations should be prescribed and labelled as the number of milligrams of etoposide base required as follows: Etoposide (as [the] PHOSPHATE) x mg. Where x is the number of milligrams of etoposide base.
Electronic prescribing and management systems must ensure any automated calculations are based on the correct formulation of etoposide and clearly identify this to prescribers, pharmacists and nursing staff.
Fatalities have occurred as a result of the inadvertent administration of bortezomib intrathecally. As bortezomib is always presented in a syringe for intravenous or subcutaneous use due to stability and administration requirements, precautions should be taken to reduce the risk of wrong route of administration. This includes labelling the final manufactured product prepared for administration with the words "For Intravenous or Subcutaneous Use Only - Fatal if Given by Other Routes" (Gilbar and Seger, 2013).
Facilities should consider internal education and the use of high risk alerts for cancer agents used locally that may cause dose or formulation confusion. For example:
(Gilbar and Seger, 2013)
- Dyer C. Doctors suspended after injecting wrong drug into spine. BMJ 2001 Feb 3;322(7281):257 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/11157519.
- Zaragoza MR, Ritchey ML, Walter A. Neurourologic consequences of accidental intrathecal vincristine: a case report. Med Pediatr Oncol 1995 Jan;24(1):61-2 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/7968797.
- Australian Commission on Safety and Quality in Health Care. High Risk Medication Alert – Vincristine. [homepage on the internet]; 2005 Dec [cited 2016 Sep]. Available from: https://safetyandquality.gov.au/wp-content/uploads/2012/01/valert.pdf.
- Vowels M. Review of Etoposide Phosphate dosing in the Oncology Unit. [homepage on the internet] Women’s and Children’s Hospital (WCH) Children, Youth and Women’s Health Service, Adelaide, South Australia.; 2008 [cited 2016 Sep]. Available from: http://www.health.sa.gov.au/Default.aspx?tabid=52&mid=449&ctl=ViewDetails&ItemID=1820&PageIndex=0.
- Carrington C, Weir J, DO C. Study to support the standardization of the prescribing, dispensing and labeling of etoposide formulations in Australia. Asia Pac J Clin Oncol 2010 Sep;6(3):173-86 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/20887498.
- Gilbar PJ, Seger AC. Accidental intrathecal administration of bortezomib: preventing fatalities. Asia Pac J Clin Oncol 2013 Sep;9(3):290-1 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/23176407.