Background Sunitinib and pazopanib are tyrosine kinase inhibitors used in the treatment of metastatic renal cancer. Pazopanib has been approved more recently, so the user experience is not as extensive as with sunitinib.

Purpose To evaluate the safety profile of pazopanib and sunitinib in patients with metastatic renal cancer.

To compare the incidence of adverse reactions between the two drugs.

Materials and Methods We identified patients treated with sunitinib and pazopanib at the hospital in the past two years, using the pharmacy database.

We looked at the medical records of patients through digital medical records, collecting dose patterns, line of therapy, adverse reactions detected, their severity and if dose reductions were necessary, using Excel.

Results A total of 26 patients with metastatic renal cancer were identified: 16 treated with sunitinib and 10 with pazopanib.

Asthenia was the most frequent drug-related toxic effect in both treatment groups, with an incidence of 93.75% for sunitinib and 60% for pazopanib.

Nausea/vomiting and diarrhoea were detected in 50% of patients treated with pazopanib. In sunitinib patients nausea/vomiting were detected in 6.25% of patients and diarrhoea was detected in 68.75% of patients

For patients who received pazopanib, the rate of mucositis was 20%, whereas for those treated with sunitinib it was 75%. Palmar-plantar erythrodysaesthesia syndrome occurred in 43.75% of those on sunitinib treatment, while none was detected for pazopanib, and the frequency of other skin pigmentation disorders for the two drugs was 62.5% and 30% respectively.

Blood pressure was decompensated in 37.5% of patients treated with sunitinib and 10% of those taking pazopanib, although most patients required antihypertensive drugs to get better control.

Dose adjustment was required of sunitinib in 43.75% of cases and in 25% pazopanib.

Conclusions Pazopanib may be better tolerated than sunitinib, with an acceptable adverse event profile and fewer dose adjustments.

Also, the severity of adverse events looks lower with pazopanib.

However, the number of patients was too small to arrive at definitive conclusions, so it is necessary to enlarge this study.

No conflict of interest.