CRD summary: This review of adults aged 20 to 63 years concluded that oral pseudoephedrine modestly increased systolic blood-pressure and heart rate, particularly with immediate-release formulations, higher doses of medication and short-term medication administration. The authors' conclusions are reasonable, but the effect of pseudoephedrine may have been overestimated given the inclusion criteria used for the review.

CRD commentary: The inclusion criteria for this review were broad and diverse studies were included. Relevant databases were searched, though for English-language studies only. The potential impact of publication bias was investigated. Although the quality assessment was conducted in duplicate, the authors did not mention any attempts to reduce bias in the study selection or data extraction processes. There was evidence of statistically significant heterogeneity. This was investigated and some relevant subgroup comparisons, specified a priori, were conducted. The authors did not consider the possible influence of pseudoephedrine indication and the presence of co-interventions on the treatment effect. The authors' conclusions appear reasonable. Despite finding a statistically significant effect of pseudophedrine, on BP and HR, the changes appeared small. The authors pointed out that the sample size might have been too small to detect rare adverse events. There is also a possibility that the effect of pseudoephedrine may have been overestimated, partly due to the exclusion of 21 studies that reported no effect of pseudoephedrine but were excluded because they did not report extractable outcome data.