Background Aging populations are often accompanied by comorbidity and polypharmacy, leading to increases in adverse drug reactions (ADRs). We sought to evaluate the causes and characteristics of ADRs in older Korean adults (≥65 years) in comparison to younger individuals (< 65 years). Methods Of 37,523 cases reported at a Korean pharmacovigilance center from 2011 to 2018, we reviewed 18,842 ADRs of certain or probable causality on the basis of WHO-UMC criteria. We estimated the number of ADRs per 1000 patients exposed to the major culprit drugs, and incidence rate ratios were obtained to assess high- and low-risk medications in older adults. Results In total, 4152 (22.0%) ADRs were reported for 3437 older adults (mean age, 74.6 years and 57.3% female). Tramadol (rate ratio, 1.32; 95% confidence interval [CI], 1.21–1.44; P < 0.001) and fentanyl (1.49, 1.16–1.92, P = 0.002) posed higher risks of ADRs in the older adults, whereas nonsteroidal anti-inflammatory drugs (NSAIDs) (0.35, 0.30–0.40, P < 0.001) and iodinated contrast media (ICM) (0.82, 0.76–0.89, P < 0.001) posed lower risks. Ratios of serious ADRs to NSAIDs (odds ratio, 2.16; 95% CI, 1.48–3.15; P < 0.001) and ICM (2.09, 1.36–3.21, P = 0.001) were higher in the older adults than in the younger patients. Analgesics primarily elicited cutaneous ADRs in the younger patients and gastrointestinal reactions in the older adults. ICM more commonly led to anaphylaxis in the older adults than the younger patients (3.0% vs. 1.6%, P = 0.019). Conclusion For early detection of ADRs in older adults, better understanding of differences in the causes and characteristics thereof in comparison to the general population is needed.

Background: Aging populations are often accompanied by comorbidity and polypharmacy, leading to increases in adverse drug reactions (ADRs). We sought to evaluate the causes and characteristics of ADRs in older Korean adults (≥65 years) in comparison to younger individuals (<65 years).Methods: Of 37,523 cases reported at a Korean pharmacovigilance center from 2011 to 2018, we reviewed 18,842 ADRs of certain or probable causality on the basis of WHO-UMC criteria. We estimated the number of ADRs per 1,000 patients exposed to the major culprit drugs, and incidence rate ratios were obtained to assess high- and low-risk medications in older adults.Results: In total, 4,152 (22.0%) ADRs were reported for 3,437 older adults (mean age, 74.6 years and 57.3% female). Tramadol (rate ratio, 1.32; 95% confidence interval [CI], 1.21-1.44; P<0.001) and fentanyl (1.49, 1.16-1.92, P=0.002) posed higher risks of ADRs in the older adults, whereas nonsteroidal anti-inflammatory drugs (NSAIDs) (0.35, 0.30-0.40, P<0.001) and iodinated contrast media (ICM) (0.82, 0.76-0.89, P<0.001) posed lower risks. Ratios of serious ADRs to NSAIDs (odds ratio, 2.16; 95% CI, 1.48-3.15; P<0.001) and ICM (2.09, 1.36-3.21, P=0.001) were higher in the older adults than in the younger patients. Analgesics primarily elicited cutaneous ADRs in the younger patients and gastrointestinal reactions in the older adults. ICM more commonly led to anaphylaxis in the older adults than the younger patients (3.0% vs. 1.6%, P=0.019). Conclusion: For early detection of ADRs in older adults, better understanding of differences in the causes and characteristics thereof in comparison to the general population is needed.

Cefaclor, a second-generation oral cephalosporin, is the most frequently prescribed cephalosporin in Korea. Studies, however, have yet to analyze the incidence of cefaclor-associated adverse drug reactions (ADRs), including hypersensitivity (HS), according to total national usage rates. This study aimed to investigate the incidence rates and clinical features of cefaclor ADRs reported to the Korean Adverse Event Reporting System (KAERS) and Health Insurance Review and Assessment Service (HIRA) database for the most recent 5 years. Reviewing the HIRA database, which contains information on all insurance claims, including prescribed medications and patient demographics, we identified the total number of individuals who had been prescribed cefaclor and other cephalosporins including 2nd generation without cefaclor and 3rd generation antibiotics from January 2014 to December 2018. Additionally, we retrospectively analyzed all ADRs reported to the KAERS for these drugs over the same study period. Incidence rates for ADRs, HS, and anaphylaxis to cefaclor were 1.92/10,000 persons, 1.17/10,000 persons, and 0.38/10,000 persons, respectively, lower than those to other 2nd and 3rd cephalosporins. Among all ADRs, HS (60.9% vs. 43.6% vs. 44.8%, P <0.001) and anaphylaxis (19.8% vs. 4.6% vs. 4.7%, P <0.001) were more common for cefaclor than for other 2nd and 3rd cephalosporins. Females, individuals under 65 years of age, concomitant use of drugs, and serious ADRs were more strongly associated with HS to cefaclor than with HS to other 2nd and 3rd cephalosporins. In a nationwide database for the Korean population, the incidence of cefaclor-induced ADRs, particularly HS and anaphylaxis, was high. Female sex, age younger than 65 years, and concomitant use of drugs may be associated with HS to cefaclor.

Background Cefaclor, a second-generation oral cephalosporin, is widely prescribed to treat infectious diseases. Immediate hypersensitivity (HS) reactions to cefaclor have continuously been reported and are expected to increase with its greater use. This study aimed to investigate the clinical characteristics and risk factors of immediate HS to cefaclor over the most recent 5 years. Methods This retrospective study investigated 521 adverse drug reactions (ADRs) to cefaclor at pharmacovigilance centers at two tertiary hospitals from January 2014 to December 2018. In total, 459 patients with immediate HS to cefaclor were reviewed. Results A total of 459 cases of cefaclor immediate HS were included among 521 cefaclor ADRs, and anaphylaxis was recorded in 61.2%. Female sex (odds ratio 2.917, 95% confidence interval 2.397–3.550, P < 0.001), age under 65 years (4.225, 3.017–5.916, P < 0.001), hypertension (2.520, 1.875–3.388, P < 0.001), liver diseases (2.189, 1.208–3.967, P = 0.010), asthma (8.075, 5.301–12.302, P < 0.001), and concomitant use of nonsteroidal anti-inflammatory drugs (1.888, 1.554–2.294, P < 0.001) were significantly associated with cefaclor immediate HS. Conclusions Cefaclor was found to elicit high proportions of immediate HS and anaphylaxis. Physicians ought to be cautious with prescribing cefaclor to females, individuals with hypertension, liver diseases, or asthma, and patients taking nonsteroidal anti-inflammatory drugs. Trial registration This study was retrospectively registered.

Background Aging populations are often accompanied by comorbidity and polypharmacy, leading to increases in adverse drug reactions (ADRs). We sought to evaluate the causes and characteristics of ADRs in older Korean adults (≥ 65 years) in comparison to younger individuals (< 65 years).Methods Of 37,523 cases reported at a Korean pharmacovigilance center from 2011 to 2018, we reviewed 18,842 ADRs of certain or probable causality on the basis of WHO-UMC criteria. Subjects exposed to major culprits were extracted from cohorts transformed to the Observational Medical Outcomes Partnership Common Data Model during the study period.Results In total, 4,152 (22.0%) ADRs were reported for 3,437 older adults (mean age, 74.6 years and 57.3% female). Tramadol (rate ratio, 1.32; 95% confidence interval [CI], 1.21–1.44; P < 0.001) and fentanyl (1.49, 1.16–1.92, P = 0.002) posed higher risks of ADRs in the older adults, whereas nonsteroidal anti-inflammatory drugs (NSAIDs) (0.35, 0.30–0.40, P < 0.001) and iodinated contrast media (ICM) (0.82, 0.76–0.89, P < 0.001) posed lower risks. Ratios of serious ADRs to NSAIDs (odds ratio, 2.16; 95% CI, 1.48–3.15; P < 0.001) and ICM (2.09, 1.36–3.21, P = 0.001) were higher in the older adults than in the younger patients. Analgesics primarily elicited cutaneous ADRs in the younger patients and gastrointestinal reactions in the older adults. ICM more commonly led to anaphylaxis in the older adults than the younger patients (3.0% vs. 1.6%, P = 0.019).Conclusion For early detection of ADRs in older adults, better understanding of differences in the causes and characteristics thereof in comparison to the general population is needed.