Comparative efficacy and safety of intravenous versus nebulized magnesium sulfate for acute asthma exacerbations: an overview of systematic reviews and meta-analyses.

OBJECTIVE

This study aimed to conduct an umbrella review comparing intravenous versus nebulized magnesium sulfate for acute asthma exacerbations, providing evidence to guide route selection and clinical decision-making.

METHODS

We systematically searched PubMed, Embase, Cochrane Library, Web of Science, CNKI, VIP, WANFANG, and CBM from inception to August 2025, for systematic reviews/meta analyses comparing intravenous versus nebulized magnesium sulfate for acute asthma exacerbations. Overlap among primary studies was assessed using a citation matrix and corrected covered area. Quality assessment was performed using ROBIS, AMSTAR-2, PRISMA 2020, and GRADE. Quantitative and qualitative analyses of primary outcomes were performed.

RESULTS

A total of 18 systematic reviews/meta analyses were included. The corrected covered area was 5.168%, indicating some overlap in primary studies. ROBIS judged all studies at low risk of bias. AMSTAR-2 rated 6 studies as high quality, 2 as moderate, and 10 as low. PRISMA 2020 scores ranged from 25.5 to 41, with 10 studies of high and 8 of moderate reporting quality. GRADE yielded 13 high-quality, 38 moderate-quality, 27 low-quality, and 26 extremely low-quality outcomes.

CONCLUSION

This overview clarifies the role of intravenous magnesium sulfate in acute asthma: not for routine use but as secondary adjunctive therapy for severe cases refractory to first-line treatment. The role of nebulized magnesium sulfate is more complex-neither universally applicable nor a replacement for first-line medications. Current evidence does not support routine use, warranting only a weak recommendation for patients who fail standard therapy. Future research should focus on its synergistic effects with other therapies and further elucidate its mechanisms.

SYSTEMATIC REVIEW REGISTRATION: https://www.crd.york.ac.uk/PROSPERO/, PROSPERO: CRD420251122150.