Too few clinical trials for pediatric migraine

October 1, 2013

Evidence on preventive drug treatments for episodic migraines in children is limited in a number of ways, a new evidence review finds.

After a systematic search of the literature, the Minnesota Evidence-based Practice Center, commissioned by the federal Agency for Healthcare Research and Quality (AHRQ), found: “Evidence was low strength due to risk of bias and imprecision” in studies of preventive pharmacologic treatments for migraines in children.

The review noted there are no preventive drugs for this condition approved specifically for children.

The review found 24 publications of randomly controlled trials (RCTs) on 1,578 children and 16 nonrandomized studies. Among other things, it found 1 RCT for propranolol that indicated it prevented migraine more effectively than placebo, saying that the drug was estimated “to result in complete cessation of migraine attacks in 713 per 1,000 children treated.” It also found “no bothersome adverse effects that could lead to treatment discontinuation.”

The review did find 1 RCT for trazodone and 1 RCT for nimodipine that showed those drugs decreased migraine days more effectively than placebo. However, studies of topiramate, divalproex, and clonidine showed them to be no more effective than placebo.

The report also found, “Sodium valproate demonstrated no significant differences for migraine prevention or migraine-related disability compared with propranolol (2 RCTs) or topiramate (1 RCT).” Asked in an interview if that means that sodium valproate is as good as propranolol for this purpose, Tatyana A. Shamliyan, MD, MS, one of the study’s authors, said she and her colleagues did not make that conclusion because the trials were different in terms of elements such as doses.

“But definitely physicians can use this information for individualized treatment decisions,” Shamliyan said. If, for example, propranolol doesn’t work, physicians might try other drugs while very carefully monitoring for adverse effects, she noted.

In studies comparing drugs with nonpharmaceutical interventions, 1 RCT found propranolol “had less effect than self-hypnosis on absolute number of migraine attacks.”

However, the report also noted that any long-term preventive benefits for drugs or other interventions are not known, nor have there been studies on quality of life or evidence for individualized treatment decisions. The report also said that no RCTs have looked at prevention of chronic, as opposed to episodic, migraines in children.

Shamliyan said that not much research has been done on the adverse effects of these drugs in children, making it difficult for physicians and parents to make decisions.

She said it has been 10 years since the last major review of this topic and, unfortunately, the lack of evidence has changed little. A Cochrane Review published in 2003 said, “There is a clear and urgent need for methodologically sound RCTs for the use of prophylactic drugs in pediatric migraine, starting with propranolol.”

Shamliyan does not know why more research has not been completed on treatment for pediatric migraine. She pointed out that she and Robert Kane, MD, published a study in 2012 in Pediatrics showing that of closed studies on all topics on children registered on ClinicalTrials.gov, only 70% were completed, and of that number only 29% were published.

Shamliyan and colleagues did a similar review for preventive drugs for migraine in adults and found different results, even though the methodology was the same. That report included the finding that, “For episodic migraine, approved drugs are effective but increase risk of adverse effects and treatment discontinuation due to adverse effects.”

The difference in the results reflects the paucity of trials conducted in the pediatric population, Shamliyan said.

The review was done under contract with the AHRQ, but the document says the conclusions do not necessarily represent AHRQ’s views.

MS FOXHALL is a freelance health writer in the Washington, DC, area. She has nothing to disclose in regard to affiliations with or financial interests in any organizations that may have an interest in any part of this article.

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