Thrombocytopenia and venous thromboembolic events after BNT162b2, CoronaVac, ChAdOx1 vaccines and SARS-CoV-2 infection: a self-controlled case series study.

This study assessed the association between COVID-19 vaccines, SARS-CoV-2 infection and the risk of thrombocytopenia and venous thromboembolism (VTE). This self-controlled case series study used hospital records between 1st February 2021 and 28th February 2022 linked to the national immunisation registry and COVID-19 surveillance data in Malaysia. Conditional Poisson regression was used to estimate incidence rate ratios (IRR) of events in the risk period (day 1-21 post-exposure) relative to control period with the corresponding 95% confidence interval (CI) adjusted for calendar period. We found no significant increased risk of thrombocytopenia in 1-21 days following BNT162b2, CoronaVac and ChAdOx1 vaccines while the risk was increased following SARS-CoV-2 infection (IRR 15.52, 95% CI 13.38-18.00). Similarly, vaccination with BNT162b2, CoronaVac, or ChAdOx1 was not associated with an increased risk of VTE during the 1-21 days risk period. SARS-CoV-2 infection was associated with increased risk of VTE (IRR 39.84, 95% CI 27.45-32.44). Our findings showed low event rates of thrombocytopenia and VTE following booster vaccination with comparable safety profiles between those who received homologous and heterologous booster combinations. Our findings showed the risk of thrombocytopenia and VTE was not increased after COVID-19 vaccination while the risks were substantially higher after SARS-CoV-2 infection.

Carbamazepine-Induced Severe Cutaneous Adverse Drug Reactions: A 21-Year Comparison Between Children and Adults in Malaysia.

Severe cutaneous adverse drug reactions (SCARs) are a life-threatening condition. We aimed to identify all carbamazepine-induced SCARs voluntarily reported to the Malaysian pharmacovigilance database and to compare between children and adults. Adverse drug reaction reports for carbamazepine were extracted from 2000 to 2020, and divided into 2 groups, that is, children (aged 0-17 years) and adults (aged 18 years and above). Age, sex, race, and carbamazepine dose were analyzed using multiple logistic regression. Of 1102 carbamazepine adverse drug reaction reports, 416 reports were SCARs (99 children, 317 adults). Stevens-Johnson syndrome and toxic epidermal necrolysis were the main SCAR types for both age groups. Median time-to-onset for any type of SCAR was 13 days, regardless of age. In children, Malay individuals were 3.6 times more likely to report SCARs (95% confidence interval, 1.356-9.546; P = .010) compared to the Chinese population. In adults, carbamazepine-induced SCARs were reported as 3.6 times higher in those with a daily dose of 200 mg or less as compared to a daily dose of 400 mg or more. (95% confidence interval, 2.257-5.758; P < .001) Carbamazepine-induced SCARs reported in Malaysia were predominantly Stevens-Johnson syndrome or toxic epidermal necrolysis, with the majority in Malay individuals. Initiation therapy needs close monitoring between 2 weeks and 1 month.

Incidence of Antiseizure Medication-Induced Severe Cutaneous Adverse Reactions in Malaysia.

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.

Incidence of allopurinol-induced severe cutaneous adverse drug reaction in Malaysia.

AIMS: 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. METHODS: 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. RESULTS: 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 × 10-4 %). CONCLUSION: The 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.

Allopurinol-Induced Severe Cutaneous Adverse Drug Reactions: An Analysis of Spontaneous Reports in Malaysia (2000-2018).

INTRODUCTION: 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. OBJECTIVES: We aimed to identify risk factors for allopurinol-induced SCARs and to assess their impact on fatality. METHODS: 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 < 0.05. RESULTS: Out of 1747 allopurinol ADR reports, 612 involved SCARs (35%). The strongest predictors significantly associated with SCARs were underlying renal disease (odds ratio [OR] 2.02; 95% confidence interval [CI] 1.36, 3.00; p = 0.001), allopurinol-prescribed dose of 300 mg/day or higher (OR 1.72; 95% CI 1.38, 2.15; p < 0.001), females (OR 1.54; 95% CI 1.24, 1.93; p < 0.001), age 65 years and above (OR 1.31; 95% CI 1.04, 1.64; p = 0.020), and allopurinol-prescribed indication. SCARs cases were higher in patients who received allopurinol for unspecified hyperuricaemia (OR 1.87; 95% CI 1.29, 2.70; p = 0.001) and off-label indications (OR 3.45; 95% CI 2.20, 5.42; p < 0.001) compared to registered indications. Fatality was associated with older age and a diagnosis of Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) overlap or TEN. CONCLUSIONS: Malaysian pharmacovigilance data show that predictors of allopurinol-induced SCARs were elderly females, patients with underlying renal disease and high allopurinol doses. These patients need close monitoring and must be educated to stop allopurinol at the first signs of rash.

Allopurinol-induced severe cutaneous adverse drug reactions: Risk minimization measures in Malaysia.

PURPOSE: To describe risk minimization measures (RMMs) implemented in Malaysia for allopurinol-induced severe cutaneous adverse drug reactions (SCARs) and examine their impact using real-world data on allopurinol usage and adverse drug reaction (ADR) reports associated with allopurinol. METHODS: Data on allopurinol ADR reports (2000-2018) were extracted from the Malaysian ADR database. We identified RMMs implemented between 2000 and 2018 from the minutes of relevant meetings and the national pharmacovigilance newsletter. We obtained allopurinol utilization data (2004-2018) from the Pharmaceutical Services Programme. To determine the impact of RMMs on ADR reporting, we considered ADR reports received within 1 year of RMM implementation. We used the Pearson χ2 test to examine the relation between the implementation of RMMs and allopurinol ADR reports. RESULTS: The 16 RMMs for allopurinol-related SCARs implemented in Malaysia involved nine risk communications, four prescriber or patient educational material, and three health system innovations. Allopurinol utilization decreased by 21.5% from 2004 to 2018. ADR reporting rates for all drugs (n = 144 507) and allopurinol (n = 1747) increased. ADR reports involving off-label use decreased by 6% from 2011. SCARs cases remained between 20% and 50%. RMMs implemented showed statistically significant reduction in ADR reports involving off-label use for August 2014 [χ2(1, N = 258) = 5.32, P = .021] and October 2016 [χ2(1, N = 349) = 3.85, P = .0499]. CONCLUSIONS: RMMs to promote the appropriate use of allopurinol and prescriber education have a positive impact. We need further measures to reduce the incidence and severity of allopurinol-induced SCARs, such as patient education and more research into pharmacogenetic screening.