POTENTIAL DRUG INTERACTIONS AND THEIR MANAGEMENT IN HOSPITALIZED OVARIAN CANCER PATIENTS

Introduction: Inpatients with ovarian cancer may be susceptible to potential drug interactions (PDI) due to exposure to various drugs. Objective: To evaluate the presence of PDI in the prescriptions of hospitalized patients with ovarian cancer and to propose management strategies. Methods: A retrospective, observational study carried out in a period of one year. We evaluated the first 24h prescription of inpatients with ovarian cancer, older than 18 years. Patients with less than 2 medications prescribed were excluded. Tumor type, age, length of stay and prescriptions data were collected from electronic medical records. CAAE 26364514.0.0000.5274. Results: A total of 236 patients were included, with a mean age of 56.34±15.07 years. The length of stay ranged from 1 to 68 days (10.17±9.74). Among the patients, 91.95% had more than 5 drugs prescribed (8.55±2.84). Opioid analgesics (19.56%), antiemetics (15.44%) and renin-angiotensin system agents (15.45%) were the most drugs prescribed. The 331 PDI founded were classified as contraindicated (1.51%), major (67.67%), moderate (24.77%) and minor (6.04%). The most observed PDI were ondansetron x tramadol (22.05%) and metoclopramide x tramadol (7.25%), both classified as major. Concomitant use of tramadol x ondansetron may increase the risk of serotonin syndrome, and the use of metoclopramide x tramadol may result in an increased risk of central nervous system depression. In both cases, it is necessary to monitor possible adverse effects or even treatment discontinuation. Prescriptions with contraindicated PDI were also observed, such as amitriptyline x metoclopramide (0.60%) and citalopram x metoclopramide (0.30%). Both PDI result in an increased risk of extrapyramidal reaction and neuroleptic malignant syndrome. It is necessary to monitor the effects to evaluate treatment discontinuation. The number of drugs was correlated with increased PDI rate (Pearson’s correlation coefficient: r=0.5971, p<0.0001). However, age (p=0.3335) and length of hospital stay (p=0.8254) were not correlated with the rate of PDI. Clinical pharmacist can prevent negative PDI outcomes, monitoring symptoms, performing intervention and providing information of therapeutic substitutes. Conclusion: Ondansetron, metoclopramide, tramadol, citalopram and amitriptyline were the drugs most related to PDI. Polypharmacy increase PDI risk in ovarian cancer patients.