Multiple Dosing Mitigates ASA Hyporesponsiveness After CABG

Multiple dosing more effective than ASA 81 or 325 mg once-daily for suppressing serum TXB2 formation


WEDNESDAY, March 22, 2017 (HealthDay News) -- Acetylsalicylic acid (ASA) hyporesponsiveness after coronary artery bypass graft (CABG) surgery can be overcome by multiple dosing, according to a study published online March 7 in the Journal of Thrombosis and Haemostasis.

Jeremy S. Paikin, M.D., from McMaster University in Hamilton, Canada, and colleagues randomized 68 adults undergoing CABG surgery to receive ASA 81 mg once-daily, 325 mg once-daily, or 162 mg twice-daily. Median serum thromboxane B2 (TXB2) level was measured on postoperative day four. The results were pooled with those of an earlier study to better assess the effect of ASA 325 mg once-daily or divided doses.

The researchers found that patients randomized to ASA 81 mg once-daily had a median day four TXB2 level of 4.2 ng/mL, compared with 1.1 ng/mL among those randomized to ASA 162 mg twice-daily and 1.9 ng/mL among those randomized to 325 mg once-daily. In pooled data, groups receiving ASA 162 mg twice-daily or 81 mg four times-daily had a median TXB2 level of 1.1 ng/mL compared with 2.2 ng/mL among those receiving ASA 325 mg once-daily.

"Multiple daily dosing of ASA is more effective than ASA 81 mg once-daily or 325 mg once-daily at suppressing serum TXB2 formation after CABG surgery," the authors write. "A twice-daily treatment regimen needs to be tested in a clinical outcome study."

The study was funded by research grants from pharmaceutical companies.

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