Parenteral Treatment of Episodic Tension-Type Headache: A Systematic Review

Danielle Weinman, MD; Olivia Nicastro, NP; Olabiyi Akala, MD; BenjaminW. Friedman, MD


Headache. 2014;54(2):260-268. 

In This Article


One limitation of this work is the paucity of data we were able to identify. Most of the studies were small with unique investigational medication regimens. Based on these data, we conclude there is a need for high-quality randomized studies to compare these various classes of medication.

Any systematic review may be limited by publication bias. We endeavored to limit this potential bias through a comprehensive search strategy including a review of online study registration sites and a review of abstracts presented at various relevant US professional societies. Studies presented only at international professional societies or registered at other websites may have been missed.

Internal bias of the individual studies may limit the validity of the conclusions of this systematic review. Using the Cochrane risk of bias tool, we have delineated the potential biases of each study. We could have excluded studies at unclear risk of bias. However, given the paucity of low bias data, we felt it is important to report all the available data.

The potential for selection bias exists whenever individuals are forced to decide which studies to include in a systematic review. We guarded against this by following a strict protocol for which studies to include, and by using two or three reviewers to review study eligibility.