Inadvertent intrathecal administration of vincristine: are we fulfilling our roles as oncology pharmacists?

Medication error prevention has been an important focus for health professionals for many years. While the incidence of errors in oncology and haematology would appear to be no greater than other specialties, the narrow therapeutic index and high toxicity of antineoplastic drugs make the consequences of chemotherapy mistakes potentially catastrophic. A number of authors have suggested strategies for the prevention of errors in cancer chemotherapy. 4 Despite this, serious errors continue to occur. As oncology pharmacists we pride ourselves on our ability to protect patients from the potential risks associated with medication errors during cancer treatment. However, are we in danger of becoming complacent? It is very easy to say ‘It can never happen to me’ or ‘It won’t happen in my institution’. Vincristine became available in the early 1960s and since the first case in 1968, there have been frequent literature reports of unintentional intrathecal administration of vincristine. In only a few of these cases has the patient survived. Over 80% of patients die of devastating neurotoxicity, the majority within four weeks of administration. Many more cases have never been published with the authors personally aware of several unpublished overseas cases in the last six months. In 2001, the death of a teenage leukaemia patient resulted in national publicity in the United Kingdom and lead to a Department of Health investigation. Since then three further cases have been reported in Europe. The tragic consequences resulting from the inadvertent spinal administration of vincristine has recently received national media attention in Australia. The 7.30 Report (ABC Television, May 5th 2004) detailed the case of a young man with Burkitt’s lymphoma erroneously administered vincristine intrathecally instead of by the intended intravenous route which resulted in progressive neurotoxicity, paralysis and death. As with other cases, a series of human and system errors combined to make this error possible. During previous cycles, intrathecal methotrexate had been administered in the radiology department while intravenous vincristine had been given in the oncology ward. With this cycle, the patient was sent to radiology without the prepared injection of intrathecal methotrexate. The radiology registrar (senior medical house officer) phoned the oncology ward and requested the medication, however, both methotrexate and vincristine were delivered. Printed on the vincristine label was the incomplete warning: ‘Fatal if give /’. This should have read: ‘Fatal if given intrathecally’. The medication record stated that vincristine be administered intravenously (abbreviated as IV) and methotrexate be given intrathecally (IT). Despite this the radiology registrar, working in a darkened room, gave both drugs intrathecally. The patient sensed that something was wrong, as the same registrar had administered only the one drug, methotrexate, intrathecally on two prior occasions. Despite the patient complaining of progressing neurological symptoms including worsening leg pain, the mistake was not discovered for nearly a week. We must ask ourselves why tragic cases such as this continue to occur despite nearly four decades of experience with vincristine. Errors commonly arise due to lapses in defensive barriers, which occur due to two reasons: active failures and latent conditions. Active failures are unsafe acts committed by people who are in direct contact with the patient or system. For example in this case, nursing staff delivering an intravenous drug to the intrathecal administration area, pharmacy staff providing a product with a potentially confusing warning label and medical staff administering the drug by the wrong route. Latent conditions are inherent problems within the system that may lie dormant for many years before they combine with active failures and local triggers to produce an accident opportunity. These included an inappropriate area for administering chemotherapy, medical staff inexperienced in the dangers of cytotoxic chemotherapy and procedural problems such as the lack of checking procedures by medical staff prior to drug administration. Reasons for the inadvertent administration of intrathecal vincristine have been examined and specific recommendations have been suggested to prevent this tragedy. However, despite this, errors J Oncol Pharm Practice (2004) 10: 187 /189