Medical Disclaimer: This database is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any treatment.
Preparing for an appointment? Bookmark treatments you want to discuss to create a printable summary for your clinician.
Showing 1 of 107 available treatments
Evidence by Condition
- MCAS · EmergingH2 blockers are a standard part of MCAS treatment; controlled evidence is small and largely from mastocytosis.
- Long COVID · InconclusiveA small double-blind RCT (n=50) found famotidine improved post-COVID cognitive and mood scores, and observational studies of H1 plus H2 blockade report improvement, but the larger open-label STIMULATE-ICP RCT found only a small, short-lived reduction in fatigue with famotidine plus loratadine.
Symptoms Addressed
Brain fogGI symptomsNeuropsychiatric symptomsMast cell activationAcid-related GI disorders
Potential Side Effects
HeadacheDizzinessConstipationQT prolongation (high doses, rare)
Mechanism of Action
H2 histamine receptor antagonist; may block SARS-CoV-2 spike-endothelial binding; reduces gastric acid; attenuates cytokine storm; synergizes with H1 blockade for MCAS
Evidence Type(s)
RCT (post-COVID cognition, small), Open-label RCT (famotidine + loratadine), Prospective observational study, Case series, Large patient survey (TREATME Study)
Key References
OTC Alternatives
Quercetin, DAO enzyme (for histamine intolerance), low-histamine diet
Want access to the full database?
You're viewing 1 of 107 treatments. Pro unlocks the full evidence database from $9 a month, and helps keep it growing.
View plans