Diphenhydramine and Migraine Treatment Failure in Pediatric Patients Receiving Prochlorperazine.

Objectives: The objectives are to determine whether diphenhydramine coadministered with prochlorperazine versus prochlorperazine only is associated with a difference in the risk of migraine treatment failure, as measured by the need for additional therapy, hospitalization rates, and 72-hour return rates, and to compare extrapyramidal adverse effects between groups.

Methods: Retrospective cohort of patients aged 7 to 18 years treated in the emergency department for migraines using prochlorperazine with or without diphenhydramine between 2013 and 2019. Patients were included if they had International Classification of Diseases, Ninth or Tenth Revision, codes for migraine or unspecified headache and were treated with prochlorperazine as part of their initial migraine therapy. Data collected included demographics, medications administered, pain scores, neuroimaging, disposition, return visits, and documentation of extrapyramidal adverse effects. Multivariable logistic regression was used to estimate the association between diphenhydramine coadministration and each of the outcomes.

Results: A total of 1683 patients were included. Overall, 13% required additional therapy with a 16.7% admission rate and a 72-hour return rate of 5.3%. There was no association between initial treatment with diphenhydramine and the odds of additional therapy (adjusted odds ratio [aOR], 0.74 [95% confidence interval {CI}, 0.53-1.03]), admission rates (aOR, 1.22 [95% CI, 0.89-1.67]), or return visit rates (aOR, 0.91 [95% CI, 0.55-1.51]). Extrapyramidal adverse effects occurred in 2.4% of patients in the prochlorperazine group and 0% in the prochlorperazine with diphenhydramine group.

Conclusions: There was no association between diphenhydramine coadministration and the need for additional therapy, 72-hour return visit rates or admission rates. Extrapyramidal effects did not occur in patients treated with diphenhydramine.