Adverse drug reactions and associated factors in patients taking levothyroxine and antithyroid drugs at Northwest hospitals, Ethiopia: A cross-sectional study

Background: Thyroid disease is a type of endocrinologic disease that should be treated early to avoid thyroid disease-related comorbidities, especially cardiovascular complications secondary to hyperthyroidism, which requires medication therapy to achieve an euthyroid state. However, patients are exposed to medication-related adverse drug reactions (ADRs) while taking drugs to treat thyroid disease. ADRs are unpredictable and unintended medication effects on the patient. Objective: This study aimed to determine the prevalence and severity of ADRs and the contributing factors of medications used for treating thyroid disease. Design: A cross-sectional study. Method: A multicenter, hospital-based study was conducted through patient interviews at public hospitals in Northwest Ethiopia. A simple random sampling technique was used to identify patients for the interview. The ADR was assessed using the Naranjo algorithm of the ADR probability scale, and the Shamrock severity of ADR assessment tool was used to identify ADR. STATA version 17 was used for data analysis. The results were summarized using descriptive statistics, including frequency, mean, median, and standard deviation. To identify the independent predictors of ADRs, logistic regression analysis was conducted, and a p -value <0.05 is considered statistically significant. Result: Among 330 study participants, 59 were experiencing ADRs. Regarding the severity of ADR, 30 (50.85%) adverse drug events were mild, 28 (47.46%) were moderate, and 1 (1.69%) was severe. Factors independently associated with ADRs were substance use (AOR = 3.48 (1.40–8.68), p = 0.007), traditional medicine users (AOR = 3.77, 95% CI: (1.13–12.54), p = 0.031), disease comorbidity (AOR = 3.58, 95% CI: (1.42–9.04), p = 0.007), and drug interaction (AOR = 2.63, 95% CI: (1.07–6.47), p = 0.035). Conclusion: The findings revealed that the incidence of ADRs among thyroid disease patients was 17.88%. Substance use, traditional medicine use, disease comorbidity, and drug interaction were the significant factors associated with ADR.