MedWire News: Ticagrelor therapy can cause a transient
and reversible dyspnea in patients free from active lung disease
without affecting their cardiac or pulmonary function, researchers
The findings, reported in the Journal of the American College
of Cardiology, support those of the Platelet Inhibition and
Patient Outcomes (PLATO) study, which suggested an increased risk
for dyspnea with ticagrelor therapy compared with clopidogrel.
However, as Robert Storey (University of Sheffield, UK) and
colleagues report: "The reversible nature of ticagrelor-related
dyspnea and the lack of any evidence of cardiac or pulmonary
pathology associated with this provide preliminary reassurance
about the nature of this side effect."
They explain that "although the mechanism for dyspnea is
unproven" adenosine may play an important role as previous studies
have shown "that intravenous infusion of adenosine to healthy
volunteers can induce dyspnea without any associated
The researchers observed 123 patients with coronary artery
disease and background aspirin therapy (75-100 mg daily). All
patients were randomly allocated to receive ticagrelor (n=57),
clopidogrel (n=54), or placebo therapy (n=12).
Cardiac and pulmonary functions were assessed via
electrocardiography, echocardiography, serum N-terminal pro-brain
natriuretic peptide, and pulmonary function tests at baseline or 6
weeks. Patients developing dyspnea before 6 weeks were additionally
assessed at onset of dyspnea.
In all, 38.6%, 9.3%, and 8.3% of patients reported dyspnea in
the ticagrelor, clopidogrel, and placebo group, respectively
(p<0.001). The majority (n=24) of the 28 reported cases of
dyspnea were described as mild, and 22 of the cases resolved upon
cessation of ticagrelor, clopidogrel, or placebo.
The researchers found no obvious changes between baseline and
6-week cardiac and pulmonary function parameters in any of the
treatment groups, even in the patients reporting dyspnea.
Of note, no evidence of transient bronchospasm or metabolic
acidosis was indicated in the spirometry and biochemical test
results of any patient.
Storey et al acknowledge that the small study size and
the selection of patients free of active lung disease are
They conclude: "Further studies of ticagrelor in patients with
active lung disease are now warranted."
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