Adverse effects of opioid analgesics during treatment of chronic pain

Abstract

Introduction. Maintaining quality of life is an important parameter during treatment. Pain is defined as an emotional, unpleasant experience, associated with present or potential tissue lesion. Pain can be part of having cancer or can be due to cancer treatment and chronic pain may cause exacerbations. Chronic pain is caused often by late stage cancer and to reduce its intensity opioids are administered. Therefore, an understanding of the pharmacology of opioids are required for their safe and appropriate use. Long-term opioid pharmacotherapy is associated with many adverse effects.Aim of the study.1. Identifying patients using opioid analgesic; 2. Patients observation during the entire period of treatment; 3. Adverse effects detection, timing when adverse reaction occurs and measures to be taken to avoid specific adverse reactions. Materials and methods. After inclusion and exclusion criteria were applied, 100 patients from Public Medical Sanitary Institution Institute of Oncology from Chisinau were selected for the study. Patients were randomized in two groups: first group (n=63 ) -patients receiving opioid analgesic during 14-35 days. Second group (n=37) –patients receiving opioids less then 14 days. Patients were administered following drugs: trimeperidine (promedol) 2% -1ml, omnopon 1% -1ml, morphine 1% - 1ml and tramadol 5% -2ml. The study period was 02.2018 - 02.2019, clinical effects were assessed by clinical examination and questionnaire. The data have been analyzed statistically using SPSS software. Results. Patients, receiving opioids from the first group experienced: constipation (89%), fatigue (60%), dyspepsia (16%), pruritus (8%), opioid withdrawal syndrome (agitation, tremors, insomnia, exacerbation of pain, neurovegetative symptoms) - 4%, and psychosis (2%). Patients from second group presented following side effects: constipation (12%), fatigue (7%).Early medication was initiated in order to prevent or to reduce adverse effects. Laxatives were administered for constipation, magnesium hydroxide was used if constipation was persistent. The dose of drug was reduced to decrease fatigue and drug was administered more frequently, lowering peak plasma-concentration. Also opioid drug changing was applied or non-opioid analgesics was included, in order to allow opioid dose reduction. Antiemetics have been administered to prevent or treat sensation of nausea and vomiting. Antihistamines was prescribed for pruritus. Doses have been reduced gradually to prevent opioid withdrawal. Antipsychotics have been administered in psychosis. Conclusions. Chronic pain can be managed and opioids adverse effects must be anticipated and treated.