Direct‐acting oral anticoagulants and alopecia: The valuable support of postmarketing data

Central Nervous System Adverse Reactions to Amantadine Intoxication: A Case Report and Analysis of JADER

BACKGROUND/AIM

A few case reports of central nervous system (CNS) symptoms caused by amantadine intoxication have been published, detailing various types of symptoms and differing times to onset. We encountered a patient who developed CNS symptoms with amantadine. This prompted us to investigate the types, time to onset, and outcome of CNS adverse reactions to amantadine by analyzing data from a pharmacovigilance database.

PATIENTS AND METHODS

The patient was evaluated at Chutoen General Hospital, Shizuoka, Japan. Analysis was performed using the Japanese Adverse Drug Event Report (JADER) database.

RESULTS

In our case, the amantadine blood concentration was 4,042 ng/ml, i.e., in the toxic range. The time to onset was 26 days for dyskinesia and 90 days for depressed level of consciousness. Symptoms resolved when amantadine was discontinued. The JADER database contained 974 cases of adverse reactions to amantadine. The most frequently reported CNS adverse reaction was hallucination, with a reporting odds ratio of 64.28 (95% confidence interval=52.67-78.46). Positive signals were detected for all CNS adverse reactions. For all CNS reactions, clinical outcomes were poor in a comparatively low percentage of cases. Most CNS reactions occurred soon after administration of amantadine, usually within approximately one month.

CONCLUSION

Because most CNS adverse reactions to amantadine usually occur within approximately one month of initiating treatment, healthcare providers should exercise heightened vigilance in monitoring patients for such reactions during this period.

Validation of alopecia coding in US claims data among women of childbearing age

BACKGROUND

Accurately identifying alopecia in claims data is important to study this rare medication side effect.

OBJECTIVES

To develop and validate a claims-based algorithm to identify alopecia in women of childbearing age.

METHODS

We linked electronic health records from a large healthcare system in Massachusetts (Mass General Brigham) with Medicaid claims data from 2016 through 2018 to identify all women aged 18 to 50 years with an ICD-10 code for alopecia, including alopecia areata, androgenic alopecia, non-scarring alopecia, or cicatricial alopecia, from a visit to the MGB system. Using eight predefined algorithms to identify alopecia in Medicaid claims data, we randomly selected 300 women for whom we reviewed their charts to validate the alopecia diagnosis. Positive predictive values (PPVs) were computed for the primary algorithm and seven algorithm variations, stratified by race.

RESULTS

Out of 300 patients with at least 1 ICD-10 code for alopecia in the Medicaid claims, 286 had chart-confirmed alopecia (PPV = 95.3%). The algorithm requiring two diagnosis codes plus one prescription claim for alopecia treatment identified 55 patients (PPV = 100%). The algorithm requiring 1 diagnosis code for alopecia plus 1 procedure claim for intralesional triamcinolone injection identified 35 patients (PPV = 100%). Across all 8 algorithms tested, the PPV varied between 95.3% and 100%. The PPV for alopecia ranged from 94% to 100% in White and 96%-100% in 48 non-White women. The exact date of alopecia onset was difficult to determine in charts.

CONCLUSION

At least one recorded ICD-10 code for alopecia in claims data identified alopecia in women of childbearing age with high accuracy.

Hypoxia-inducible Factor Prolyl Hydroxylase Inhibitors and Hypothyroidism: An Analysis of the Japanese Pharmacovigilance Database

BACKGROUND/AIM

Hypothyroidism induced by roxadustat, a hypoxia-inducible factor prolyl hydroxylase (HIF-PH) inhibitor, was recently reported; however, information regarding roxadustat-associated hypothyroidism is still lacking. We explored the risk and time to onset of hypothyroidism associated with HIF-PH inhibitors using the Japanese Adverse Drug Event Report (JADER), a pharmacovigilance database.

PATIENTS AND METHODS

The participants of this study were registered in the JADER database between April 2004 and March 2023. The association between HIF-PH inhibitors and hypothyroidism was evaluated using the reporting odds ratio (ROR) and information component (IC). We also calculated the period from the start of drug administration to the onset of hypothyroidism and determined the onset pattern using Weibull distribution.

RESULTS

Roxadustat had positive signals for hypothyroidism among the HIF-PH inhibitors based on the ROR [31.03, 95% confidence interval (CI)=27.81-34.62] and IC (4.51, 95%CI=4.36-4.67) values, and a strong relationship was confirmed. In addition, the median time to roxadustat-associated hypothyroidism onset was 92 days, and over 50% of cases occurred within 100 days of starting treatment. Furthermore, the onset pattern was an early failure type.

CONCLUSION

There is a possible association between roxadustat and hypothyroidism. Therefore, enhanced thyroid function testing within 100 days of treatment initiation may help detect roxadustat-associated hypothyroidism. However, further research is required to confirm these findings, considering study limitations using databases of spontaneous adverse event reports.