Background Severe intoxication with high dose methotrexate is life threatening, and hence determining contributing factors can help early rescue.

Purpose To analyse the correlation between nausea and vomiting (72 h before or during chemotherapy) based on high dose methotrexate (MTX) and achieving highly toxic levels.

Material and methods Analytical, observational and retrospective study in a reference hospital.

All patients that had reached toxic levels after being treated with high doses of MTX, from January 2014 to September 2015, were included.

The following variables were collected: sex, age, weight (kg), height (cm), body surface area (m²), disease, chemotherapy protocol, number of cycles administered, toxic values achieved and time at which they were achieved (relative to cut-off highly toxic level at that time), and presence or absence of nausea and vomiting before or during infusion, measured by the CTC 3.0 Scale for adverse events in patients with cancer.

Statistical analysis of the data was performed using SPSS and the Spearman test.

Results 7 patients were analysed, 57.1% male, mean age 20.14 ± 5.7 years and average body surface area 1.5 ± 0.20 m². 42.9% had a diagnosis of osteosarcoma (OS), 42.9% acute lymphoblastic leukaemia (ALL) and 14.3% non-Hodgkin lymphoma (NHL). 57.1% received MTX at a dose of 5 g/m² in 24 h and 42.9% at 12 g/m² in 4 h. The average number of cycles received was 3.

Mean plasma levels of MTX, expressed relative to the cut-off values established as highly toxic, were 2.3 ± 1.66.

28.6% of patients had no episodes of nausea and vomiting, 42.9% occurred during infusion of MTX and 28.6% in the previous 72 h.

The degree of emesis according to the CTC 3.0 Scale was 0% to 28.6%, 1% to 14.3% and 2% to 57.1%.

The value of rho Spearman coefficient was 0.653 with no statistical significance (0.11).

Conclusion The correlations found between plasma levels of MTX and nausea and vomiting, before and during infusion of  high dose methotrexate, were moderate but not statistically significant, possibly due to the low number of patients with highly toxic levels of methotrexate.

No conflict of interest.