Background and Importance The use of phytotherapy is very widespread. Onco-haematology patients are particularly at risk of drug or phytotherapeutic interactions that may compromise the efficacy and safety of chemotherapy treatment.

Aim and Objectives To detect patients who consume phytotherapeutic products as well as their interactions with anticancer agents in onco-haematology patients and to provide pharmaceutical interventions to optimise treatment.

Material and Methods Prospective observational study of onco-haematology patients in a tertiary hospital from January 2023 to August 2023. Demographic variables (age, sex, pathology) were collected. To identify the type of intervention performed, a database was created using an Excel® spreadsheet to record and categorise it. Interactions were detected using the applications Drugs®, Lexicomp® and About Herb®. The pharmacological intervention was recorded in electronic medical records.

Results Sixty-three patients were found to be taking herbal medicine concomitantly with onco-haematologic treatment. 57% of patients were women. The median age was 62 [61.5–65.4] years. The patients belonged to two clinical services, 39.6% to Haematology and 60.4% to Oncology. The most frequent onco-haematologic pathologies: Prostate Cancer (33%), Colon Cancer (23%), Chronic Lymphocytic Leukaemia (12%), Multiple Myeloma (11%), Ovarian Cancer (8%), Brain Tumours (5%), Lung Cancer (6%) and Breast Cancer (2%). The main supplements with a potential risk of interactions were echinacea (39%), magnesium (32%), green tea (21%), soy (5%), capsaicin (4%), ashwagandha (1%) and devil’s claw (1%). The potential consequences were an increase or a decrease in the concentration of the anticancer agents (82%), an increase in the risk of bleeding (13%), hepatotoxicity (3%), and hypokalaemia (2%). The consumption of phytotherapy was unknown by a health professional for 48% of the patients. 100% of the pharmaceutical interventions were entered in the patient‘s clinical history as a clinical report. 95% were accepted and prevented errors of medication errors in patients.

Conclusion and Relevance The risk of interactions between plants and antineoplastic agents is frequently observed in clinical practice and due to its increasing popularity, healthcare professionals need to be alert. Multidisciplinary teams working together can detect this problem and avoid loss of effectiveness or toxicity of chemotherapy treatment.

Conflict of Interest No conflict of interest.