Background Prescription errors, especially in oncology, may lead to clinical, financial and organisational damage. A second check by the pharmacist before preparation may prevent errors and related harm to the patient.

Purpose To measure the effectiveness of pharmacist intervention in preventing errors and creating a safety-oriented vision in healthcare givers.

Materials and methods Near miss reports, resulting from serious errors in the prescription of non-muscle infiltrating bladder cancer (NMIBC) instillation treatments, were collected by software (Vitruvio 2.0) during the second half of 2012 (Jun–Dec). Errors were analysed and presented to urologists during their departmental meetings.

In the first half of 2013 (Jan–Jun) data collection was repeated, observing and analysing data using the same criteria as the previous six months.

Results The incidence of serious errors in 2012 was 6.6% of total prescriptions (35/530). The main mistake was ‘incorrect dose’ (14), the second one was ‘organisational error’ including double prescription, wrong date and others (13) and the third more frequent error was ‘wrong active’ prescription (8).

We identified the practice of using a duplication function in prescribing with subsequent data change in the prescription form as the main cause predisposing to error.

Data were analysed and discussed during the urology department meeting, after the meeting we collected data for an additional 6 months.

The results of the second period (2013) showed a strong reduction in the incidence of serious errors (7/441). Organisational errors were the most frequent, (5) typology, while there was a marked reduction of ‘dose errors’ (1) or ‘wrong active’ prescription (1).

Conclusions The pharmacist intervention not only produced a prevention in terms of possible harm to the patient (incidence reduction = 24.04%), but even produced an improvement in clinical practice and safety orientation of the culture amongst clinical personnel.

No conflict of interest.