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Allopurinol is known to cause severe cutaneous adverse drug reactions (SCAR) in Malaysia. However, the incidence of allopurinol-induced SCAR is unknown. Therefore, we aimed to determine the incidence of allopurinol-induced SCAR in Malaysia over 5 years from 2015 to 2019.This retrospective analysis was done in collaboration with the National Pharmaceutical Regulatory Agency (NPRA). All allopurinol-induced adverse drug reaction cases reported to NPRA from 2015 to 2019 were extracted. Allopurinol-induced SCAR cases were identified and the incidence over the 5 years was calculated.Incidence of allopurinol-induced SCAR averaged at 2.5 cases per 1000 new users over the 5-year period, with a reducing trend from 3.2 per 1000 new users in 2015 to 2.25 per 1000 in 2019; despite the increasing number of adverse drug reaction cases being reported over the years. Stevens-Johnson syndrome was the commonest form of allopurinol-induced SCAR reported, at 143 cases (46.8% of total SCAR reported). Among Malaysia's 3 main ethnicities, the Chinese had the highest percentages of allopurinol-induced SCAR when compared to the Bumiputera and Indians (3.18 × 10The estimated incidence of allopurinol-induced SCAR in Malaysia from 2015 to 2019 was 2.5 cases per 1000 new users. This figure is consistent with the incidence reported in other Asian countries, namely Taiwan and Thailand.

Antiseizure medication can potentially cause severe cutaneous adverse reactions, and certain antiseizure medication-induced severe cutaneous adverse reactions are associated with specific human leukocyte antigen alleles. This caused a change in antiseizure medication prescribing patterns, which may influence the incidence of antiseizure medication-induced severe cutaneous adverse reactions. Thus, we aimed to determine the incidence of antiseizure medication-induced severe cutaneous adverse reactions and its change over 15 years (2006-2019) in Malaysia. This retrospective analysis combined antiseizure medication-induced SCAR cases from the national adverse drug reaction database in the National Pharmaceutical Regulatory Agency, antiseizure medication usage data from the Malaysian Statistics of Medicine, and prescribing data from University Malaya Medical Centre, a national-level tertiary hospital to calculate antiseizure medication-induced SCAR incidence in Malaysia. We observed an upward trend in reported antiseizure medication-induced SCAR cases from 28 cases in 2006 to 92 in 2016. The incidence of carbamazepine (CBZ)-induced severe cutaneous adverse reactions increased from 7.5 per 1000 person-years (2006) to 17.8 per 1000 person-years (2016) but dropped to 7.2 per 1000 person-years subsequently (2019). Concurrently, there was an increase in the incidence of severe cutaneous adverse reactions secondary to phenytoin and lamotrigine. The prevalent users of CBZ had reduced from 22.8% (2006) to 14.1% (2016), whereas the levetiracetam and sodium valproate users increased by 5.5% and 4.8%, respectively. The incidence of CBZ-induced severe cutaneous adverse reactions had reduced since 2016, probably related to the implementation of human leukocyte antigen-B*1502 screening in Malaysia or substitution of CBZ with other antiseizure medications. However, this was accompanied by an increase in SCAR incidence related to phenytoin and lamotrigine.

BackgroundRapid deployment of COVID-19 vaccines is challenging for safety surveillance, especially on adverse events of special interest (AESIs) that were not identified during the pre-licensure studies. This study evaluated the risk of hospitalisations for predefined diagnoses among the vaccinated population in Malaysia. MethodsHospital admissions for selected diagnoses between 1 February 2021 and 30 September 2021 were linked to the national COVID-19 immunisation register. We conducted self-controlled case-series study by identifying individuals who received COVID-19 vaccine and diagnosis of thrombocytopenia,venous thromboembolism,myocardial infarction, myocarditis/pericarditis, arrhythmia, stroke, Bell’s Palsy, and convulsion/seizure. The incidence of events was assessed in risk period of 21days postvaccination relative to the control period. We used conditional Poisson regression to calculate the incidence rate ratio (IRR) and 95% confidence interval (CI) with adjustment for calendar period. ResultsThere was no increase in the risk for myocarditis/pericarditis, Bell’s Palsy, stroke, and myocardial infarction in the 21days following either dose of BNT162b2, CoronaVac, and ChAdOx1 vaccines. A small increased risk of venous thromboembolism (IRR 1.24; 95% CI 1.02, 1.49), arrhythmia (IRR 1.16, 95% CI 1.07, 1.26), and convulsion/seizure (IRR 1.26; 95% CI 1.07, 1.48) was observed among BNT162b2 recipients. No association between CoronaVac vaccine was found with all events except arrhythmia (IRR 1.15; 95% CI 1.01, 1.30). ChAdOx1 vaccine showed significant association for thrombocytopenia (IRR 2.67; 95% CI 1.21, 5.89) and venous thromboembolism (IRR 2.22; 95% CI 1.17, 4.21). ConclusionThis study shows acceptable safety profiles of COVID-19 vaccines among recipients of BNT162b2, CoronaVac, and ChAdOx1 vaccines. This information can be used together with effectiveness data for risk-benefit analysis of the vaccination program. Further surveillance with more data is required to assess AESIs following COVID-19 vaccination in short- and long-term.

Allopurinol-induced severe cutaneous adverse drug reactions (SCARs) are potentially debilitating and life-threatening reactions, which can cause a financial burden to the healthcare system. We aimed to identify risk factors for allopurinol-induced SCARs and to assess their impact on fatality. Adverse drug reaction (ADR) reports with allopurinol as suspected drug were extracted from the Malaysian pharmacovigilance database from year 2000 to 2018. Multiple logistic regression analysis was used to identify significant predictors of allopurinol-induced SCARs. We further analysed the association between covariates and SCARs-related fatality in a separate model. Level of significance was set at p value