Efficacy of high-dose ambroxol for paraquat poisoning: A meta-analysis of randomized controlled trials

BACKGROUND: Paraquat (PQ) poisoning is characterized by rapidly progressive acute poisoning with high mortality and no specific antidote. Although some clinical studies have been conducted to investigate the benefits of high-dose ambroxol as an adjuvant treatment for PQ poisoning, the efficacy is controversial. MATERIALS AND METHODS: After searching for relevant articles in English and Chinese databases from 1978 to 2019 according to the keywords (paraquat poisoning/methy viologen/gramoxone, and ambroxol/mucosolvan/Bromhexine), we found seven articles that met our inclusion and exclusion criteria. A meta-analysis was performed using fixed-effects model and random-effects model according to the I(2) value in Stata software (version 15.0). Four outcome indicators (hospital mortality, partial pressure of oxygen (PaO(2)), oxygenation index (PaO(2)/FiO(2)), and survival time of the deceased patients) were of interest to us. RESULTS: The meta-analysis showed that adjuvant treatment with high doses of ambroxol increased PaO(2) (weighted mean difference [WMD] = 13.73 [mmHg], 95% confidence interval [CI]: 8.68–18.79, Z = 11.80, P < 0.001), PaO(2)/FiO(2) (WMD = 38.81 [mmHg], 95% CI: 29.85–47.76, Z = 8.49, P = 0.000), and survival time of the deceased patients (WMD = 2.58 [d], 95% CI: 0.97–4.18, Z = 3.15, P = 0.002) compared with usual treatment. Treatment with high doses of ambroxol also appeared to reduce the hospital mortality (relative risk = 0.69, 95% CI: 0.55–0.86, Z = 3.25, P = 0.001). CONCLUSION: This study found that high-dose ambroxol is an effective therapy for PQ poisoning and may reduce the in-hospital mortality.