A Real-World Disproportionality Analysis of Histamine H2-Receptors Antagonists (Famotidine): A Pharmacovigilance Study Based on Spontaneous Reports in the FDA Adverse Event Reporting System

Famotidine is an H2 receptor antagonist and is currently used on a large scale in gastroenterology. However, Famotidine may also cause severe toxicity to organ systems, including the blood system, digestive system, and urinary system. The objective of this study was to scientifically and systematically investigate the adverse events (AEs) of Famotidine in the real world through the FDA Adverse Event Reporting System (FAERS) database. A disproportionality analysis was used to quantify the signals of AEs associated with Famotidine in FAERS data from the first quarter of 2004 to the first quarter of 2023. The clinical features, onset time, oral and intravenous administration and severe consequences of Famotidine induced AEs were further analyzed. Among the four tests, we found several AEs that were not mentioned in the drug label. For example, abdominal pain upper, abdominal discomfort, dyspepsia, liver disorder, gastrooesophageal reflux disease, and rhabdomyolysis. These AEs are consistent with the drug instructions. Interestingly, we found several unreported AEs, such as: cerebral infarction, hypocalcaemia, hallucination, visual, hypomagnesaemia, hypoparathyroidism, diabetes insipidus, vulvovaginal candidiasis, retro-orbital neoplasm, neuroblastoma recurrent, and malignant cranial nerve neoplasm. Most of our findings are consistent with clinical observations and drug labels, and we also found possible new and unexpected AEs signals, which suggest the need for prospective clinical studies to confirm these results and explain their relationships. Our findings provide valuable evidence for further safety studies.