Safety profile of methotrexate used off-label in ectopic pregnancy: an active monitoring study based on a Chinese hospital pharmacovigilance system

Abstract

Objective

Methotrexate (MTX) is characterized as first-line therapy although its indication of ectopic pregnancy is off-label use. We aimed to conduct a retrospective cohort study to investigate the incidence, characteristics of adverse drug reactions (ADRs) of MTX, provide valuable insights for medical workers.

Methods

Basing on China Hospital Pharmacovigilance System (CHPS), a retrospective analysis was performed to evaluate the safety of MTX (n = 672). An active monitoring model was set to detect ADR signals from the hospital information system. Frequency, Common Terminology Criteria for Adverse Events (CTCAE) grade proportion and association of dose exposure with ADRs were presented as outcomes.

Results

The total incidence of ADRs was 54.0%. Anaemia (37.6%) was the most frequent ADR, followed by hepatic function abnormal (11.3%), hyperuricemia (6.1%), neutropenia (4.6%), leukopenia (4.0%), and dyslipidaemia (2.5%). For the composition of all ADRs, CTCAE grade one, two and three dominated for 86.3%, 12.1% and 1.6%, respectively. The severity of hepatic function abnormal was more serious in the two-dose exposed group (p = .021), while other types of ADRs had no statistical or clinical differences. Logistic regression analysis showed the incidence of any ADRs (OR 1.87 [1.31–2.64]; p = .001), hepatic function abnormal (OR 2.75 [1.69–4.48]; p < .001), dyslipidaemia (OR 5.15 [1.87–14.13]; p = .001) were significantly higher in the two-dose exposed group. After adjusted, the positive associations were still maintained.

Conclusions

MTX is quite safe in ectopic pregnancy, despite its mild to moderate hematotoxicity, hepatotoxicity and nephrotoxicity. Taking CHPS can present the accurate denominator of the incidence of adverse drug reactions into account, our study advocates that it may have great potential to be used as an active monitoring tool for off-label drug use risk management.

Keywords:

• Drug safety
• hospital pharmacovigilance system
• active monitoring
• methotrexate
• off-label use

Transparency

Declaration of funding

This study was not funded.

Declaration of financial/other relationships

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Author contributions

Lingsong Wang and Yao Chen conceived this study. Lingsong Wang and Danni Shi performed the data extraction, Can Cai and Quanyao Chen performed statistical analysis. Lurong Huang analysed and interpreted the results. Lingsong Wang and Can Cai draught out the initial manuscript. Yao Chen and Weiwei Yu reviewed the manuscript as well as supervised the study. All authors have read and agreed to the published version of the manuscript.

Acknowledgements

No assistance in the preparation of this article is to be declared.