How best to reduce injection pain—lidocaine cream
A comparison of 4 levels of pain management of routine vaccine injections found that of the remedies tried, only liposomal lidocaine applied at the injection site provided consistent relief.
Investigators in Canada divided 352 infants into 4 groups representing increasing levels of pain management for routine vaccine injections: 1) placebo control (asking parents to do what they think best via a video and administering oral and topical placebo); 2) parent-directed video education about infant soothing; 3) the video plus orally administered sucrose; and 4) the video plus sucrose plus topically applied lidocaine. Researchers then assessed infant distress associated with injections at 2, 4, 6, and 12 months before injection, during injection, and 1 minute after injection (recovery phase), using the Modified Behavioral Pain Scale to assess grimacing, crying, and body movements.
When used consistently during the 4 sets of routine vaccine injections in the first year, only lidocaine combined with parental video instruction and sucrose (group 4) showed a benefit on acute pain compared with the other regimens (groups 1, 2, and 3), while none of the regimens showed a benefit over the others during the vaccination recovery phase. Across all groups, infants showed fewer pain responses over time up to the age of 6 months, with an increase at age 12 months (Taddio A, et al. CMAJ. December 12, 2016. [Epub ahead of print]).
Although a regimen including topical lidocaine offered the best pain reduction in this study, it may be difficult to build consensus for its use in your practice. The gel must be applied 20 minutes prior to immunizations, it has a cost, and whereas pain scores improved before and during administration, there was no effect 1 minute later. And the impact, while statistically significant, may lack clinical significance. It may be time to look again at the use of topical vapocoolant spray for reducing pain with immunizations. This is a quick, inexpensive option with evidence to support its use (Reis EC, et al. Pediatrics. 1997;100:e5). Ethyl chloride is now used for this versus the fluori-methane described in the original study. —Michael G Burke, MD