What do systematic reviews say?

H2 receptor antagonists vs placebo or no prophylaxis

H2 receptor antagonists showed no clear difference in all‐cause mortality in ICU compared with placebo or no prophylaxis (low certainty).

• Interventions for preventing upper gastrointestinal bleeding in people admitted to intensive care units 2018 · Cochrane Headline outcomes only
  RR 1.12 [0.88, 1.42]
  14 studies · 1428 participants
  Low