Reviewed: Ertürk NE, Taşci S. The effects of peppermint oil on nausea, vomiting and retching in cancer patients undergoing chemotherapy: An open label quasi-randomized controlled pilot study. Complement Ther Med. January 2021;56:102587. doi:10.1016/j.ctim.2020.102587.
Nausea and vomiting are common adverse effects of chemotherapy and can lead to electrolyte imbalance, dehydration, weight loss, decreased kidney function, and other physiological changes. Additionally, nausea and vomiting affect a person’s social and work lives, daily activities, and psychological well-being. Conventional pharmaceutical drugs used to manage nausea and vomiting can cause further adverse effects, such as heartburn, insomnia, headache, dizziness, constipation/diarrhea, and dry mouth. Alternatively, aromatherapy is used to cope with chemotherapy-induced nausea and vomiting. However, few studies have assessed its efficacy. These authors conducted an open-label, quasi-randomized controlled pilot study to evaluate the effects of aromatherapy using peppermint (Mentha × piperita, Lamiaceae) essential oil in patients undergoing chemotherapy.
The study was conducted in the ambulatory chemotherapy unit of a public hospital in Batman, Turkey. Included participants were at least 18 years old, were able to communicate in Turkish, had a cancer diagnosis at stage 3 or below, had nausea, had two remaining chemotherapy treatments using similar chemotherapeutic agents, were not pregnant, and had no psychiatric disorders.
From September 2017 to September 2018, the authors screened 250 patients with cancer who were undergoing chemotherapy. Of those patients, 140 met the inclusion criteria, and 90 agreed to participate in the study.
Forty-five patients were assigned to the intervention group and 45 were assigned to the control group. In the intervention group, four patients decided not to participate after the start of the study, three discontinued the study because of increased severity of nausea, and two dropped out due to mild headaches. In the control group, one patient decided to quit the study. The final analysis included 36 patients in the intervention group and 44 patients in the control group. The patients were aged 49.9 ± 10.5 years in the intervention group and 54.6 ± 10.2 years in the control group. Baseline characteristics were similar in both groups.
Data were collected at baseline and on each of the five days after chemotherapy by using a patient information form, a visual analog scale (VAS) for nausea severity, a patient watch chart, the Index of Nausea, Vomiting, and Retching (INVR), and a patient opinion form on aromatherapy practice. The VAS for nausea severity and INVR were the primary outcome measures. The authors also used semi-structured questionnaires and individual in-depth interviews with the patients before they had chemotherapy and at the end of follow-up.
Before chemotherapy, all patients were prescribed an intravenous corticosteroid (16 mg dexamethasone) and anti-nausea drugs (3 mg granisetron and 10 mg metoclopramide). After chemotherapy, the patients were prescribed antiemetic prophylaxis (8 mg ondansetron and 10 mg metoclopramide) to use at home.
The control group did not receive aromatherapy. The patients in the intervention group applied one drop of the aromatic oil mixture between their upper lip and nose three times daily (morning, afternoon, and evening) for five days after chemotherapy. They were instructed to breathe deeply after applying the mixture. The mixture consisted of 3% peppermint essential oil in sweet almond (Prunus dulcis, Rosaceae) oil as the carrier. The aromatic oil mixture was prepared with essential oil by Nu-Ka Defne Essencia in Alanya, Turkey. Due to the distinctive aroma of peppermint oil, blinding was not possible.
In the intervention group, the VAS nausea severity score decreased significantly compared with baseline in patients receiving these chemotherapy regimens: folfirinox (P < 0.001), paclitaxel-trastuzumab (P = 0.014), carboplatin-paclitaxel (P < 0.001), and cyclophosphamide-Adriamycin (P = 0.005). VAS nausea severity scores also were significantly lower in the intervention group compared with the control group (except for carboplatin-paclitaxel on the evening after chemotherapy and cyclophosphamide-adriamycin on the evening after chemotherapy and on the first day after treatment). No significant changes were seen in the patients who received the chemotherapy medication cisplatin or in patients in the control group. (According to the authors, the participants “were compared according to the chemotherapy treatment protocols due to the chemotherapy agents’ different emetogenic [nausea- and vomiting-inducing] potentials.”)
The INVR daily scores of patients who received folfirinox, paclitaxel-trastuzumab, carboplatin-paclitaxel, and cyclophosphamide-Adriamycin were lower in the intervention group compared with the control group (except in patients receiving paclitaxel-trastuzumab on the first day); the between-group differences were significant at each time point (P < 0.05 for all).
In this study, aromatherapy using peppermint essential oil significantly reduced the frequency of nausea, vomiting, and retching and the severity of nausea in patients with cancer who were undergoing chemotherapy, except in those treated with cisplatin.