Famotidine associated with better outcomes from COVID-19
Simon Collins, HIV i-Base
Two studies have reported positive outcomes from COVID-19 in adults using the histamine-2 receptor antagonist famotidine.
The larger study included 1620 adults hospitalised with COVID-19 between 25 February and 13 April 2020 of whom 84 (5.1%) received famotidine. Home use of famotidine on admission was documented in 15% of those given famotidine group vs in 1% of those who were not (p=0.01). 
Overall, 28% of the famotidine group were dosed intravenously: 17% were 10 mg, 47% were 20 mg and 35% were 40 mg. Total median dose of 136 mg (63 to 233 mg) was given over a median of 5 days.
A total of 340 participants (21%) met the primary composite endpoint of death or intubation: 142 (8.8%) patients were intubated and 238 (15%) died.
In adjusted analyses, famotidine was independently associated with risk for death or intubation (adj. HR 0.42, 95% CI: 0.21 to 0.85) which remained after propensity score matching to further balance the covariables (HR: 0.43, 95%CI: 0.21 to 0.88).
This study also found no benefit of proton pump inhibitors or impact of famotidine in people hospitalised who did not have COVID-19.
A second more recent study also reported reduced mortality and intubation associated with famotidine. 
This was a retrospective analysis of 878 adults hospitalised with COVID-19 of whom 83 (9.5%) used famotidine. The control group were slightly younger (mean 63 vs 67 years, p=0.02) but propensity-matched for baseline demographics and comorbidities.
Famotidine was associated with decreased risk of in-hospital mortality (OR 0.37, 95%CI: 0.16 to 0.86, p=0.021) and combined death/intubation (OR 0.47, 95%CI: 0.23 to 0.96, p=0.040).
Although these associations are important enough to report and famotidine is safe and widely used, results from two phase 3 randomised studies are needed to demonstrate efficacy. [3. 4]
- DE et al. Famotidine use Is associated with improved clinical outcomes in hospitalized COVID-19 patients: a propensity score matched retrospective cohort study. Gastroenterology, DOI: 10.1053/j.gastro.2020.05.053. (22 May 2020).
- Mather JF et al. Impact of famotidine use on clinical outcomes of hospitalised COVID-19 patients. American Journal of Gastroenterology. (14 August 2020).
- Role of famotidine in the symptomatic improvement of COVID-19 patients.
- Multi-site adaptive trials for COVID-19.