Management of Gastrointestinal Symptoms in Long COVID Patients

Diagnosis and Testing

The American Gastroenterological Association recommends testing for GI pathogens, including Clostridium difficile, especially with risk factors like recent antibiotic use, to rule out other causes of persistent GI symptoms 1

The British Society of Gastroenterology recommends following their guidance for medication management in patients with inflammatory bowel disease and long COVID 2
Antihistamine therapy, combining H1 antihistamines (e.g., cetirizine) with H2 antihistamines (e.g., famotidine), is recommended as first-line therapy for gastrointestinal symptoms in long COVID patients, with monitoring of QTc interval when combining with other medications that may prolong QT 1
Loperamide (antidiarrheal) is recommended for diarrhea, and anti-emetics with careful QTc monitoring are recommended for nausea/vomiting 1
Low-dose naltrexone (1-4.5mg) may be considered for patients with neuroinflammation, pain, and fatigue, as it has shown promise in treating both long COVID and ME/CFS symptoms 3
Mast cell stabilizers may be added if antihistamines alone are insufficient, following protocols similar to those used for mast cell activation syndrome 3

A low-histamine elimination diet may help reduce dietary histamine load, with a focus on fresh foods rather than aged, fermented, or preserved items, and consideration of probiotics to help restore gut microbiota balance 3
Consider digestive enzymes with DAO (diamine oxidase) to help break down histamine 3

Coenzyme Q10 and D-ribose may help with fatigue, and have natural antihistamine properties 3
Vitamin C and quercetin may be considered for their natural antihistamine properties 3
Probiotics may help with both gastrointestinal and non-gastrointestinal symptoms 3

Patients with post-exertional malaise should avoid exercise, as physical activity worsens symptoms in 75% of long COVID patients and improves symptoms in less than 1% 3
Implement energy conservation techniques and activity pacing, using heart rate monitoring to stay within safe zones, and apply similar pacing principles to mental activities, breaking cognitive tasks into smaller segments with rest periods 3
Regular assessment of symptom severity using validated tools, adjusting treatment based on response, and monitoring for medication side effects, particularly with long-term antihistamine use, is recommended 3
Be aware of potential sedating effects when combining multiple antihistamines, and set realistic expectations, as these interventions typically manage symptoms rather than providing a cure 3