Should the clinical study on opioid-induced cough continue?

Comparison of Lidocaine and Atropine on Fentanyl-Induced Cough: A Randomized Controlled Study

Objective of the Study: Fentanyl and atropine are drugs used for analgesia during induction and for premedication, respectively. The aim of this study was to observe the effect of atropine used for premedication on cough developing in association with fentanyl use during anesthesia induction. Methods: This was a single-blind, prospective, multi-arm, parallel, randomized clinical trial involving 120 patients between ages 3 and 15 years undergoing general anesthesia. Patients were randomized into three groups: a control group (Group C), an atropine group (Group A), and a lidocaine group (Group L). Results: Incidence of cough was 45% (n = 16) in Group C, 16% (n = 6) in Group A, and 16% in Group L (n = 6) (p = 0.009). Cough was moderate in two cases in Group A and in two in Group L, and mild in all others in these groups. In Group C, cough was mild in seven cases, moderate in six, and severe in two. Conclusion: We determined that premedication with atropine suppressed the incidence and severity of fentanyl-induced cough during induction of general anesthesia. We think that, due to its antimuscarinic effect, atropine is as effective as lidocaine as a premedication.

The impact of prophylactic intravenous lidocaine on opioid-induced cough: a meta-analysis of randomized controlled trials

BACKGROUND

Opioids are commonly used for general anesthesia, but reflex cough can occur after an intravenous injection. We have performed a meta-analysis of randomized controlled trials (RCTs) that evaluated the effectiveness and safety of prophylactic lidocaine administered intravenously (IV) on opioid-induced cough (OIC) during induction in patients undergoing general anesthesia.

METHODS

We searched three bibliographic databases (PubMed, Embase, and the Cochrane Central Register of Controlled Trials) to identify studies meeting a priori inclusion criteria and also conducted a secondary reference review. The information used to calculate the relationship between lidocaine prophylaxis and the risk and severity of OIC was extracted by two principal investigators, respectively.

RESULTS

Six RCTs with a total of 1,740 participants were included in this meta-analysis. Overall, prophylactic lidocaine administered IV reduced both the risk of OIC [pooled risk ratio (RR) 0.471; 95 % confidence interval (CI) 0.355-0.625; P = 0.074; heterogeneity test, I (2) = 50.3 %] and its severity (weighed mean difference -0.316; 95 % CI -0.480 to -0.151; P = 0.038; heterogeneity test, I (2) = 60.5 %). Sub-group analysis indicated a significant reduction in the incidence of both fentanyl-induced cough (FIC) and remifentanil-induced cough (RIC), but it appeared that lidocaine only alleviated the severity of FIC. Further sub-group analysis indicated that the lowest effect dose of lidocaine for preventing the prevalence of OIC was 0.5 mg/kg. No severe adverse effects were reported.

CONCLUSIONS

Our meta-analysis establishes the effectiveness of prophylactic lidocaine administered IV for the prevention of OIC during induction. The lowest effective dose of lidocaine on the risk of OIC appeared to be 0.5 mg/kg.