Reply

Singh et al¹ are interested in the formulation of famotidine received by patients in our study and whether there was concurrent antacid use. In our retrospective study,² 15% of patients who received famotidine during hospitalization for Coronavirus Disease 2019 (COVID-19) had home use of famotidine documented on the electronic medication reconciliation that must be performed at the time of hospital admission (compared with 1% of patients who did not receive famotidine during hospitalization for COVID-19, P < .01). Accuracy of medication reconciliation can be poor, and this may have been especially true for over-the-counter medications, such as famotidine, during the peak of the pandemic. Manually reviewing charts, 55% of patients who received famotidine during hospitalization for COVID-19 had either documentation of gastroesophageal reflux disease or documentation of famotidine use in the hospital admission note. Although this leaves room for uncertainty, we believe the most likely explanation for receipt of famotidine during hospitalization was continuation of home use of famotidine.

Regarding dose and formulation, the median dose of famotidine received during hospitalization was 136 mg (interquartile range 63–233) over a median of 5.8 days. The famotidine in our study was predominantly manufactured by Major Pharmaceuticals (oral) and West-Ward Pharmaceuticals (intravenous). Neither of these manufacturers was involved in the study. Regarding mode of administration, there were only 84 patients who received famotidine, including some who received both oral and intravenous formulations, so there is insufficient power to compare clinical outcomes based on mode of administration of famotidine. We could not determine from the medical records whether outpatient famotidine formulations included calcium carbonate; concomitant use of antacids during hospitalization was not assessed, but is rare at our institution.

Cheung et al³ present cross-sectional data related to famotidine exposure and severe COVID-19. The temporal relationship between famotidine exposure and outcomes in their study is unclear (ie, it is unclear whether famotidine administration preceded or followed the clinical outcomes). Several retrospective studies show relationships between famotidine and outcomes in COVID-194, 5, 6 and several do not.^{3 , 7 , 8} Additional retrospective (or cross-sectional) studies are unlikely to produce definitive answers for this question. Like Cheung et al³ and like Singh et al,¹ we eagerly await the results of the ongoing randomized controlled trial testing famotidine in hospitalized patients with COVID-19 (NCT04370262).