Preoperative Famotidine Dosing for Aspiration Pneumonia Prevention

Famotidine Administration and Efficacy

• The American Society of Anesthesiologists recommends oral famotidine 40 mg administered at least 3 hours before surgery to reduce gastric volume and increase gastric pH, thereby decreasing aspiration risk 1, 2, 3
• Orally-administered famotidine is effective in reducing gastric volume and acidity during the perioperative period, with Category A2-B evidence 1, 4
• Intramuscular famotidine has similar efficacy according to placebo-controlled RCT evidence, with Category A3-B evidence 1, 4

Patient Selection and Risk Factors

• The American Society of Anesthesiologists suggests that histamine-2 receptor antagonists like famotidine should not be routinely administered to all patients, but reserved for those at increased risk of pulmonary aspiration 1, 3, 4
• Risk factors for aspiration include emergency surgery, obesity, pregnancy, difficult airway, gastroesophageal reflux disease, and delayed gastric emptying 1, 3

Aspiration Prevention Strategy

• Famotidine should be part of a comprehensive aspiration prevention strategy that includes appropriate fasting guidelines, such as 6 hours for light meals and 8 hours for fatty meals 3, 5
• The American Society of Anesthesiologists notes that the literature is insufficient to evaluate the direct effect of histamine-2 receptor antagonists on perioperative pulmonary aspiration or emesis/reflux, though they effectively modify the risk factors 1, 4