Medications
Browse medicines in the published stepwise sequence, with emergency, trigger-specific, emerging or refractory, and local-route options kept in separate groups. Every card keeps how the treatment relates to mast cells, the types of studies cited, the conditions studied and regulatory approval separate.
Nothing here is approved for MCAS, and almost nothing has been tested in it. Most entries draw their studies from another condition or from laboratory work; the few direct MCAS reports are uncontrolled. Each card says which. The numbered groups report a published stepwise sequence. Emergency treatment appears before it; trigger-specific, emerging or refractory, and local-route treatments each sit in their own group. Everything else remains outside the sequence. Within a group, entries follow the order the review itself describes where it describes one. Where it does not, an internal direct-study rank sets browsing order; it is not a usefulness or treatment score. Every card shows the literal facts behind that order and states which conditions are actually approved or trialled.
34 entries. No dosing, and no claim that anything here works. How this is decided.
Emergency intervention — time-critical acute treatment, not a maintenance step
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Epinephrine Non-selective alpha- and beta-adrenergic receptor agonist
How it relates: Downstream of the mast cell Study types: Cohort study
Time-critical adrenergic emergency treatment for anaphylaxis, kept separate from the maintenance sequence and from mast-cell stabilisation.
- Approved in the US for
- emergency treatment of type I allergic reactions, including anaphylaxis (auto-injector)
- Catalog context
- Emergency intervention
Recently verified. Verified 24 Aug 2026
1. H1 antihistamines — described as the initial treatment, with second-generation agents prioritised over first
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Cetirizine H1 antihistamine
How it relates: Downstream of the mast cell Study types: Randomised controlled trial
Second-generation H1 antihistamine; blocks the H1 receptor and can still cause drowsiness despite a lower-sedation class profile.
- Approved in the US for
- hay fever and upper respiratory allergy symptoms
- Randomised trials in
- chronic spontaneous urticaria
- Also covers
- Levocetirizine (Xyzal), Fexofenadine (Allegra), Loratadine (Claritin), Desloratadine (Clarinex), Bilastine, Bepotastine
Recently verified. Verified 21 Aug 2026
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Hydroxyzine First-generation H1 receptor antagonist
How it relates: Mast cell disease Study types: Randomised controlled trial
First-generation H1 antihistamine; blocks histamine after release and has prominent central nervous system and cardiac safety boundaries.
- Approved in the US for
- histamine-mediated pruritus, including chronic urticaria
- Randomised trials in
- pediatric mastocytosis
- Also covers
- Diphenhydramine (Benadryl), Chlorpheniramine (Chlor-Trimeton), Clemastine (Tavist), Cyproheptadine
Recently verified. Verified 25 Aug 2026
2. H2 antihistamines — described as add-on therapy where episodes involve gastrointestinal symptoms
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Famotidine H2 antihistamine
How it relates: Downstream of the mast cell Study types: Randomised controlled trial
H2 antihistamine; blocks the histamine H2 receptor, the principal mediator of gastric acid secretion.
- Approved in the US for
- heartburn from acid indigestion, duodenal and gastric ulcer, gastro-oesophageal reflux disease and erosive oesophagitis, pathological hypersecretory conditions
- Randomised trials in
- acute urticaria
- Also covers
- Cimetidine (Tagamet), Nizatidine (Axid)
Recently verified. Verified 22 Aug 2026
3. Leukotriene receptor antagonists — the next class described; in Canada montelukast is the only available option
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Montelukast Leukotriene receptor antagonist
How it relates: Downstream of the mast cell Study types: Randomised controlled trial
Cysteinyl leukotriene receptor antagonist; blocks a mast cell mediator class that antihistamines do not address.
- Approved in the US for
- asthma, exercise-induced bronchoconstriction, allergic rhinitis
- Randomised trials in
- chronic urticaria
- Also covers
- Zafirlukast (Accolate), Pranlukast
Recently verified. Verified 21 Aug 2026
4. Cromolyn — described for persistent gastrointestinal symptoms despite H1 and H2 blockade
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Cromolyn sodium Mast cell stabiliser
How it relates: MCAS patients Study types: Case series
Oral mast cell stabiliser with randomized systemic-mastocytosis evidence and a five-person retrospective MCAS case series.
- Approved in the US for
- mastocytosis
- Randomised trials in
- systemic mastocytosis
Recently verified. Verified 24 Aug 2026
5. Ketotifen — described for patients not controlled on high-dose second-generation H1 antihistamines
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Ketotifen H1 antihistamine / mast cell stabiliser
How it relates: Mast cell disease Study types: Randomised controlled trial
H1 antihistamine with additional mast cell stabilising activity; oral formulations are approved outside the US but not by the FDA.
- Approved in the US for
- itchy eyes from allergen exposure
- Randomised trials in
- urticaria pigmentosa, paediatric mastocytosis
Recently verified. Verified 22 Aug 2026
6. Aspirin — described as limited evidence, for persistent episodes despite H1 blockade
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Aspirin Cyclooxygenase inhibitor / nonsteroidal anti-inflammatory drug
How it relates: MCAS patients Study types: Case series
Cyclooxygenase inhibitor that changes prostaglandin synthesis; direct MCAS evidence is a small retrospective subgroup, with important reaction and bleeding warnings.
- Approved in the US for
- temporary relief of minor aches and pains
Recently verified. Verified 21 Aug 2026
7. Oral corticosteroids — described for frequent episodes, with use limited by adverse effects
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Systemic corticosteroids (prednisone representative) Systemic glucocorticoid receptor agonist class
How it relates: Related inflammatory condition Study types: Case series , Cohort study
Step-7 class in a 2025 practical MCAS approach, supported by uncontrolled idiopathic-anaphylaxis records rather than an MCAS comparison.
- Approved in the US for
- severe or incapacitating allergic conditions intractable to conventional treatment (prednisone tablets)
- Also covers
- Prednisone, Prednisolone, Methylprednisolone, Dexamethasone
Recently verified. Verified 24 Aug 2026
8. Omalizumab — described for severe recurrent reactions despite the preceding treatments
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Omalizumab Anti-IgE monoclonal antibody
How it relates: MCAS patients Study types: Case series , Cohort study
Anti-IgE monoclonal antibody; reduces free IgE and downregulates the high-affinity IgE receptor on mast cells and basophils.
- Approved in the US for
- allergic asthma, chronic spontaneous urticaria, chronic rhinosinusitis with nasal polyps, IgE-mediated food allergy
- Randomised trials in
- chronic spontaneous urticaria, IgE-mediated food allergy
Recently verified. Verified 21 Aug 2026
Trigger-specific treatment — directed at a defined sensitization or trigger
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Hymenoptera venom immunotherapy Allergen-specific subcutaneous immunotherapy with standardized Hymenoptera venom extracts
How it relates: Mast cell disease Study types: Cohort study
Trigger-specific allergen immunotherapy studied prospectively in systemic mastocytosis with confirmed Hymenoptera venom allergy.
- Approved in the US for
- diagnosed sensitivity to the relevant Hymenoptera venom after a significant systemic sting reaction
- Catalog context
- Trigger-specific treatment
Recently verified. Verified 24 Aug 2026
Emerging / refractory evidence — direct reports or surveys outside the routine stepwise sequence
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Benzodiazepines (lorazepam representative) Benzodiazepine GABA-A positive allosteric modulator class
How it relates: MCAS patients Study types: Cross-sectional survey , Human mast cells in vitro
Class-level MCAS survey exposure and compound-specific mast-cell experiments, with lorazepam used only as the regulatory representative.
- Approved in the US for
- anxiety disorders or short-term relief of anxiety symptoms (lorazepam tablets)
- Catalog context
- Emerging / refractory evidence
- Clinical practice
- Documented specialist use
Recently verified. Verified 24 Aug 2026
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Hydroxychloroquine 4-aminoquinoline antimalarial and lysosomal immunomodulator
How it relates: MCAS patients Study types: Case series , Human mast cells in vitro
Mixed four-person mast-cell-disease report and primary human mast-cell experiments, with separate randomised evidence in chronic urticaria.
- Approved in the US for
- uncomplicated malaria and prophylaxis where chloroquine resistance is not reported, rheumatoid arthritis in adults, systemic lupus erythematosus in adults, chronic discoid lupus erythematosus in adults
- Randomised trials in
- antihistamine-refractory chronic spontaneous urticaria
- Catalog context
- Emerging / refractory evidence
Recently verified. Verified 24 Aug 2026 Trial status unknown
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Hydroxyurea Ribonucleotide reductase inhibitor and cytotoxic antimetabolite
How it relates: MCAS patients Study types: Case series
Cytotoxic antimetabolite documented in two uncontrolled MCAS series, with extensive concurrent treatment and major monitoring boundaries.
- Approved in the US for
- resistant chronic myeloid leukemia, locally advanced squamous cell head and neck cancers with chemoradiation, sickle cell anemia with recurrent moderate to severe painful crises
- Catalog context
- Emerging / refractory evidence
- Clinical practice
- Documented specialist use
Recently verified. Verified 21 Aug 2026
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Low-dose naltrexone Opioid receptor antagonist used in a low-dose off-label regimen
How it relates: MCAS patients Study types: Cross-sectional survey , Cohort study , Case report
Off-label use of an opioid-receptor antagonist, documented in an MCAS survey, a small pain cohort, and bundled case-level evidence.
- Approved in the US for
- alcohol dependence, blockade of the effects of exogenously administered opioids
- Catalog context
- Emerging / refractory evidence
- Clinical practice
- Documented specialist use
Recently verified. Verified 21 Aug 2026
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Sunitinib Multitargeted receptor tyrosine kinase inhibitor
How it relates: MCAS patients Study types: Case report
Multitargeted oncology kinase inhibitor represented by one MCAS case and a separate systemic-mastocytosis case with limiting toxicities.
- Approved in the US for
- gastrointestinal stromal tumor after progression on or intolerance to imatinib, advanced renal cell carcinoma, adjuvant treatment after nephrectomy for renal cell carcinoma at high recurrence risk, progressive unresectable or metastatic pancreatic neuroendocrine tumors
- Catalog context
- Emerging / refractory evidence
Recently verified. Verified 21 Aug 2026
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Tofacitinib Janus kinase inhibitor with JAK1 and JAK3 activity
How it relates: MCAS patients Study types: Case report
Broad JAK inhibitor represented in MCAS by a two-patient report, without a comparison group or measured mast-cell effect.
- Approved in the US for
- rheumatoid arthritis after inadequate response or intolerance to TNF blockers, psoriatic arthritis after inadequate response or intolerance to TNF blockers, ankylosing spondylitis after inadequate response or intolerance to TNF blockers, ulcerative colitis after inadequate response or intolerance to TNF blockers, polyarticular-course juvenile idiopathic arthritis after TNF-blocker failure
- Catalog context
- Emerging / refractory evidence
Recently verified. Verified 21 Aug 2026
Local-route symptom treatments — route-specific products, not systemic MCAS interventions
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Olopatadine ophthalmic solution Topical H1-receptor antagonist with local mast-cell mediator-release effects
How it relates: Mast-cell-mediated condition Study types: Randomised controlled trial
Local ocular H1-antihistamine product with a small randomized allergen-challenge study that measured tear histamine after exposure.
- Approved in the US for
- temporary relief of itchy eyes due to named environmental allergens (ophthalmic product)
- Catalog context
- Local-route symptom treatment
Recently verified. Verified 24 Aug 2026
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Azelastine nasal spray Topical intranasal H1-receptor antagonist
How it relates: Related inflammatory condition Study types: Randomised controlled trial
Local H1-antihistamine nasal product with randomized allergic-rhinitis evidence, separated from a historical oral mastocytosis trial.
- Approved in the US for
- nasal symptoms due to hay fever or other upper respiratory allergies (OTC nasal product)
- Catalog context
- Local-route symptom treatment
Recently verified. Verified 24 Aug 2026
Outside that sequence — not part of the stepwise approach the review describes
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Avapritinib Selective tyrosine kinase inhibitor (KIT D816V)
How it relates: Mast cell disease Study types: Randomised controlled trial
Selective KIT D816V inhibitor; the first agent in mast cell disease supported by a placebo-controlled randomised trial.
- Approved in the US for
- indolent systemic mastocytosis, advanced systemic mastocytosis, PDGFRA exon 18 gastrointestinal stromal tumour
- Randomised trials in
- indolent systemic mastocytosis
Recently verified. Verified 21 Aug 2026
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Barzolvolimab Anti-KIT monoclonal antibody
How it relates: Mast-cell-mediated condition Study types: Randomised controlled trial , Cohort study
Investigational anti-KIT monoclonal antibody; human studies measure mast-cell depletion in chronic urticaria rather than MCAS.
- Randomised trials in
- chronic spontaneous urticaria
- Approved for
- nothing — Investigational
Recently verified. Verified 21 Aug 2026
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Dupilumab Interleukin-4 receptor alpha antagonist
How it relates: Mast-cell-mediated condition Study types: Randomised controlled trial , Case report
IL-4Rα monoclonal antibody; approved for CSU and other type-2 diseases, with human nasal mast-cell-count data and one idiopathic-anaphylaxis case.
- Approved in the US for
- atopic dermatitis, asthma with an eosinophilic phenotype or oral corticosteroid dependence, chronic rhinosinusitis with nasal polyps, eosinophilic esophagitis, prurigo nodularis, COPD with an eosinophilic phenotype, chronic spontaneous urticaria, bullous pemphigoid, allergic fungal rhinosinusitis after sino-nasal surgery
- Randomised trials in
- chronic spontaneous urticaria, chronic rhinosinusitis with nasal polyps
Recently verified. Verified 21 Aug 2026
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Masitinib Tyrosine kinase inhibitor (KIT, LYN, FYN)
How it relates: Mast cell disease Study types: Randomised controlled trial
Investigational KIT and LYN kinase inhibitor; studied in indolent systemic mastocytosis, with no current regulatory approval.
- Randomised trials in
- indolent systemic mastocytosis
- Approved for
- nothing — Investigational
Recently verified. Verified 20 Aug 2026 Trial status unknown
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Rupatadine H1 antihistamine / platelet-activating-factor receptor antagonist
How it relates: Mast cell disease Study types: Randomised controlled trial , Human mast cells in vitro
H1 and platelet-activating-factor receptor antagonist with a small randomised crossover study in adults with mastocytosis.
- Approved outside the US for
- seasonal and perennial allergic rhinitis, chronic spontaneous urticaria
- Randomised trials in
- mastocytosis
Recently verified. Verified 21 Aug 2026
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Zileuton Leukotriene synthesis inhibitor
How it relates: Mast-cell-mediated condition Study types: Randomised controlled trial , Animal model
5-lipoxygenase inhibitor; prevents leukotriene synthesis and has human mast-cell pharmacodynamic data from aspirin-sensitive asthma.
- Approved in the US for
- asthma
- Randomised trials in
- aspirin-sensitive asthma nasal challenge
Recently verified. Verified 21 Aug 2026
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Cyclosporine Calcineurin inhibitor and systemic immunosuppressant
How it relates: Mast cell disease Study types: Case report , Human mast cells in vitro
Systemic calcineurin immunosuppressant with combination-therapy case reports in systemic mastocytosis and randomized chronic-urticaria evidence.
- Approved in the US for
- prevention of rejection after kidney, liver, or heart transplantation, severe active rheumatoid arthritis with inadequate methotrexate response, severe recalcitrant plaque psoriasis in selected adults
- Randomised trials in
- chronic idiopathic urticaria
Recently verified. Verified 21 Aug 2026
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GLP-1-based medicines GLP-1-receptor agonists and dual GIP/GLP-1-receptor agonists
How it relates: MCAS patients Study types: Case series , Case report
Incretin-based drug class with a 47-person retrospective MCAS case series; no randomised MCAS comparison or established direct human mast-cell mechanism.
- Approved in the US for
- chronic weight management in obesity or overweight (specific formulations), obstructive sleep apnea in adults with obesity (tirzepatide)
- Clinical practice
- Documented specialist use
Recently verified. Verified 21 Aug 2026
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Imatinib Tyrosine kinase inhibitor (KIT, PDGFR, BCR-ABL)
How it relates: MCAS patients Study types: Case report , Cohort study
KIT and PDGFR tyrosine kinase inhibitor with a treating-author MCAS report and a mutation-limited US mastocytosis indication.
- Approved in the US for
- aggressive systemic mastocytosis without KIT D816V or with unknown KIT status
- Clinical practice
- Documented specialist use
Recently verified. Verified 21 Aug 2026
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Midostaurin Multikinase inhibitor (KIT, FLT3, PDGFR, PKC)
How it relates: Mast cell disease Study types: Cohort study
Multikinase inhibitor active against wild-type and D816V-mutant KIT; approved for defined advanced systemic mastocytosis diagnoses, not MCAS.
- Approved in the US for
- advanced systemic mastocytosis, including ASM, SM-AHN, and mast cell leukemia
Recently verified. Verified 21 Aug 2026
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Remibrutinib Bruton tyrosine kinase inhibitor
How it relates: Mast cells in the laboratory Study types: Human mast cells in vitro
Bruton tyrosine kinase inhibitor studied in cultured human mast cells and approved by the FDA for chronic spontaneous urticaria.
- Approved in the US for
- chronic spontaneous urticaria
- Randomised trials in
- chronic spontaneous urticaria
Recently verified. Verified 21 Aug 2026
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Doxepin (oral capsules) Tricyclic antidepressant and H1/H2 receptor antagonist
How it relates: Mast cells in the laboratory Study types: Non-human mast cells in vitro
Tricyclic antidepressant with strong H1 and H2 antihistamine activity; studied in a small urticaria trial and non-human mast cells.
- Approved in the US for
- major depressive disorder in adults
- Randomised trials in
- chronic idiopathic urticaria
Recently verified. Verified 21 Aug 2026
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Proton pump inhibitors (omeprazole representative) Gastric proton pump inhibitor
How it relates: Mast cells in the laboratory Study types: Animal model
Acid-suppressing drugs listed on patient-facing mast cell resources for reflux symptoms; a mouse study reports mast-cell effects, with no human MCAS data.
- Approved in the US for
- frequent heartburn
- Also covers
- Esomeprazole (Nexium), Lansoprazole (Prevacid), Pantoprazole (Protonix), Rabeprazole (Aciphex), Dexlansoprazole (Dexilant)
Recently verified. Verified 25 Aug 2026
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Tranilast Mast-cell mediator-release inhibitor
How it relates: Mast cells in the laboratory Study types: Non-human mast cells in vitro , Animal model
Oral anti-allergic medicine approved in Japan; direct mast-cell experiments measure mediator release and exocytosis in rat cells.
- Approved outside the US for
- bronchial asthma, allergic rhinitis, atopic dermatitis, keloids and hypertrophic scars
Recently verified. Verified 21 Aug 2026
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TLL-018 TYK2/JAK1 inhibitor
How it relates: Related inflammatory condition Study types: Randomised controlled trial
Investigational TYK2/JAK1 inhibitor with a small randomized chronic-spontaneous-urticaria pilot and no measured mast-cell or MCAS outcome.
- Randomised trials in
- chronic spontaneous urticaria
- Approved for
- nothing — Investigational
Recently verified. Verified 21 Aug 2026