Rupatadine
H1 antihistamine / platelet-activating-factor receptor antagonist · also known as Rupall
H1 and platelet-activating-factor receptor antagonist with a small randomised crossover study in adults with mastocytosis.
- How it relates to mast cells
- Mast cell disease
- Types of studies cited
- Randomised controlled trial , Human mast cells in vitro
- Approved outside the US for
- seasonal and perennial allergic rhinitis, chronic spontaneous urticaria
- Randomised trials in
- mastocytosis
What this relationship means: Studied in patients with a different mast cell disease, usually systemic mastocytosis. Those disorders have diagnostic criteria and disease biology that differ from MCAS, so a result there does not establish an MCAS outcome.
Mechanism of action
Rupatadine is a second-generation H1 antihistamine that also antagonises the platelet-activating-factor receptor. H1 blockade acts downstream of mast-cell degranulation by preventing released histamine from signalling at that receptor. Platelet-activating factor is a separate lipid mediator that can participate in amplification of mast-cell activation.
The MASPAF laboratory study compared rupatadine with other antihistamines in LAD2 cells and primary mast cells isolated from human lung tissue. It examined platelet-activating-factor-induced degranulation and supports the dual-receptor description, but it was not a clinical study.
A randomised, double-blind, placebo-controlled crossover trial enrolled 30 adults with mastocytosis and assessed mediator-related symptoms and quality of life. Mastocytosis is a different disease from MCAS, and the small crossover design cannot be treated as direct MCAS evidence. Health Canada’s product monograph lists allergic rhinitis and chronic spontaneous urticaria—not mastocytosis or MCAS—as authorised indications.
Approved elsewhere — off-label rationale
Health Canada authorises oral Rupall for symptoms of seasonal and perennial allergic rhinitis and chronic spontaneous urticaria. Neither the Canadian product monograph nor the published mastocytosis trial establishes an authorised indication for MCAS; the non-US approval is relevant because the same oral drug has been studied in another mast-cell disease.
Sources
- Rupall (rupatadine) Canadian product monograph Drug label 2023 · link checked 21 Aug 2026
- Rupatadine improves quality of life in mastocytosis: a randomized, double-blind, placebo-controlled trial Peer-reviewed study 2013 PMID 23734572 · link checked 21 Aug 2026
- Effects of Rupatadine on Platelet-Activating Factor-Induced Human Mast Cell Degranulation Compared With Desloratadine and Levocetirizine (The MASPAF Study) Peer-reviewed study 2017 PMID 27758758 · link checked 21 Aug 2026