Metamizole in Pain Management for Patients with Subarachnoid Hemorrhage

Introduction

Various analgesics are used to alleviate the intense headaches in patients with subarachnoid hemorrhage. Individual preparations can also affect various pathophysiological pathways. Therefore, experts from Brno tried to evaluate whether metamizole has a significant impact on the development of ischemic complications and hydrocephalus and how it affects overall outcomes in patients with subarachnoid hemorrhage from an aneurysm compared to other non-opioid analgesics and opioids.

Study Methodology and Evaluated Patient Population

This was a retrospective cohort study conducted at a single center. A total of 192 patients with subarachnoid hemorrhage were included, with assessment of their initial clinical condition, comorbidities, and the administered analgesic, including daily dosage during the 14-day hospitalization following the hemorrhage onset. Using univariate and multivariate logistic regression, the authors evaluated the impact of various factors, including administered analgesics, on the development of delayed cerebral ischemia and hydrocephalus and on treatment outcomes at 2 weeks and 6 months.

Results

Although the administration of non-opioid analgesics did not generally impact the development of delayed cerebral ischemia or hydrocephalus, the prescription of metamizole as the main analgesic was associated with a significantly lower probability of adverse outcomes at 2 weeks and 6 months after the hemorrhage onset and also a significantly lower probability of delayed cerebral ischemia. Opioids were primarily indicated for analgesosedation in patients with mechanical ventilation support in poor clinical condition. Their administration was associated with a significantly higher likelihood of adverse treatment outcomes, development of delayed cerebral ischemia, and hydrocephalus.

Conclusion and Discussion

The findings of Czech experts suggest that using metamizole in pain management for patients with subarachnoid hemorrhage may be associated with better clinical outcomes in both the short-term and longer-term perspective and a lower probability of developing cerebral ischemia and hydrocephalus compared to other non-opioid analgesics. However, the authors themselves point out that this is a retrospective evaluation, and the benefits of metamizole in these patients need to be confirmed in future prospective studies.

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Source: Solár P., Joukal M., Šilar Č., Jančálek R. Impact of analgesic regimen on patient outcome following subarachnoid hemorrhage: positive adjuvant effects of metamizole. Br J Neurosurg 2022 Dec 5, doi: 10.1080/02688697.2022.2151563 [Epub ahead of print].