Dados do Trabalho

Título

POLYPHARMACY AND DRUG INTERACTION IN PATIENTS TREATING COLORECTAL CANCER WITH OXALIPLATIN AND CAPECITABINE (XELOX)

Introdução

Polypharmacy is an important issue for patients with cancer since they use a large number of drugs including chemotherapy regimens and supportive care. Most of these patients have co-morbid conditions that also requires treatment wich increase the risk of drug interaction, impaired treatment efficacy and drug related toxicity. Detection, monitoring and managing these interactions can improve outcomes and avoid hospitalization.

Objetivo

The aim of this study was to investigate the prevalence of polypharmacy and drug interaction in patients treating colorectal cancer with oxaliplatin and capecitabine in a public hospital in Rio de Janeiro.

Método

This was a prospective study carried out between June 2020 and June 2021, approved by ethics committee under the registry CAAE 39906820.6.0000.5243. Colorectal cancer patients in treatment with the combination of capecitabine and oxaliplatin receive pharmaceutical care before every infusion. Information about medication use was collected during the service. Polypharmacy were defined as taking 5 or more medications. Potencial drug interaction that contraindicate the concurrent use and the ones that indicate major severity were screened using IBM Micromedex Drug Interactions®.

Resultado

Forty eight patients receive pharmaceutical care during that period and all of them were using more than 5 medications. Two potential drug interactions that contraindicate the association were found and they both involved the use of metoclopramide and other drugs for central nervous system (escitalopram and amitriptyline). 127 major interactions were found in prescriptions. All patients had, at least, one interaction between Oxaliplatin and Ondansetron that can cause QT interval prolongation and ventricular arrhythmias and must be monitored closely. 12 patients presented a potential interaction in which omeprazole can decrease solubility and absorption of capecitabine, reducing bioavailability and efficacy. Dexamethasone was involved 10 cases of potential interaction. As a CYP3A4 inducer, it may reduce plasma levels of opioids such as tramadol and codeine. It was not possible to make a correlation between number of medicines taken and number of interactions.

Conclusão

Polypharmacy and drug interactions were found to be very prevalent in this population. Monitoring closely is important to reduce toxicity, hospitalization and emergency visits. It is important to make efforts towards reducing prescriptions and make a rational use of medicines.

Palavras-chave

Drug Interactions, Pharmaceutical Care, Colorectal Neoplasms