Awareness and attitudes of oncology specialists toward dihydropyrimidine dehydrogenase testing in Saudi Arabia.

BACKGROUND: Fluoropyrimidines (FP) are among the most common class of prescribed anti-neoplastic drugs. This class has severe to moderate toxicity in around 10%-40% of those who take 5-fluorouracil (5-FU) or capecitabine for the treatment of cancer. In practice many patients with severe toxicities from FP use had dihydropyrimidine dehydrogenase (DPD) enzyme deficiency. Several studies have proposed DPD screening before treatment with 5-fluorouracil (5-FU) and capecitabine or other drugs belonging to the FP group. This study aims to assess the level of awareness and attitudes of oncology specialists in Saudi Arabia toward genetic screening for DPD prior to giving FP. This highlights the importance of health guidelines required for implementation in our health care system, as a framework to adopt testing as a regular practice in clinical care. Based on the findings in this study, guidelines have been suggested for the Middle East North Africa region. METHODS: A cross-sectional survey study was conducted during 2021 targeting oncologists and clinical pharmacists working in the oncology departments across Saudi Arabia. RESULTS: A total of 130 oncologists and pharmacists completed the questionnaire representing a response rate of 87%. Most of the respondents indicated that they prescribe FP in clinical practice, but 41% of respondents reported that they have never ordered a specific molecular test during their practice. Only 20% of respondents reported that they often screen for DPD deficiency prior to prescribing FP. Significantly higher rates of awareness of potential dihydropyrimidine dehydrogenase gene (DPYD) mutation were observed among respondents in governmental hospitals (81.1% vs. 47.4% in private hospitals), and among those with more years of practice (80.6% if 5 or more years of practice vs. 59.3% if less than 5 years of practice). Also, higher rates of observing the impact of DPD testing were present among respondents with a PharmD (35% vs. 11% for oncologists and 18% for other professions) and among those with 5 or more years of practice (24.6% vs. 7.7% among those with less than 5 years). CONCLUSION: While in some institutions there is a high level of awareness among oncology specialists in Saudi Arabia regarding the effect of the potentially serious DPD enzyme deficiency as a result of gene mutations, screening for these mutations prior to prescribing FP is not a routine practice in hospitals across the country. The findings of this study should promote personalized medicine with recognition of interpatient variability via DPD testing to manage the risks of FP prescribing more effectively in the Kingdom of Saudi Arabia.

A highlight on carbamazepine-induced adverse drug reactions in Saudi Arabia: a retrospective medical records-based study.

The link between human leukocyte antigen (HLA) alleles and carbamazepine-induced cutaneous, respiratory, and gastrointestinal adverse drug reactions (ADR) has created a window of opportunity for preventing certain forms of cutaneous adverse drug reactions (cADRs); however, there is not enough data to make pharmacogenomic recommendations that can be implemented globally. The aim of this study is to assess and document carbamazepine-induced adverse reactions among prescribed Saudi/non-Saudi patients. A retrospective chart review was performed for patients who received carbamazepine (CBZ) in the period between 2016 and 2020, in the Kingdom of Saudi Arabia. Data were gathered and descriptive statistical analyses were performed on the data for the study sample. Comparisons were made using the chi-square test or independent samples' t-test. Statistical significance was considered at p < .05. All statistical analyses were performed using IBM SPSS 21.0 (Armonk, NY; IBM Corp). Results from multivariate logistic regression analyses showed that higher likelihood of carbamazepine-induced adverse reactions was significantly associated with younger age, OR = 0.82, 95% CI (0.74, 0.90); p < 0.001. Patients who were prescribed CBZ for reasons other than epilepsy or seizures were significantly more likely to develop carbamazepine-induced adverse reactions (epilepsy vs. other; OR = 0.63, p = 0.013; seizures vs. other; OR = 0.59, p = 0.018). Gender or medication duration were not related to carbamazepine-induced adverse reactions (p > 0.05). The findings of this study are comparable with those of other studies assessing carbamazepine-associated adverse reactions in children and adults. Recommendations include genetic prescreening, educating patients and parents on the possibility of adverse reactions, and routine laboratory monitoring.