Effects of enteric-coated, low-dose aspirin on parameters of platelet function.
BACKGROUND
Aspirin is widely used as an anti-thrombotic drug; however, it has been suggested that enteric-coated formulations of aspirin may be less bioavailable and less effective as anti-thrombotic agents.


OBJECTIVE
To assess the effect of a formulation of enteric-coated, low-dose (81 mg) aspirin on serum generated thromboxane B2 and platelet aggregation in healthy subjects.


METHODS
Twenty-four subjects participated in a double-blind, randomized, placebo-controlled, parallel-group, multiple-dose study. Twelve subjects in each of two groups received a daily oral dose of enteric-coated aspirin (81 mg) or matching placebo for 7 days. Serum thromboxane B2 and platelet aggregation (using 1 mm arachidonic acid and 1 microg/mL collagen as agonists) were measured 1-3 days prior to day 1, on day 1 (prior to therapy) and 4 h after the last dose on day 7.


RESULTS
After seven daily doses of enteric-coated aspirin, the mean percentage inhibition from baseline of ex vivo generated serum thromboxane B2 was 97.4%, compared with a 7.8% increase after placebo treatment. The mean percentage inhibition of arachidonic acid- and collagen-induced platelet aggregation was 97.9% and 70.9%, respectively, following enteric-coated aspirin, compared with - 1.0% and 2.7%, respectively, after placebo.


CONCLUSIONS
The anti-platelet effects of multiple, daily, low-dose aspirin (as assessed by inhibition of serum thromboxane B2 and platelet aggregation) are not adversely affected by enteric coating.
Center for Clinical Pharmacology, University Hospital Gasthuisberg, Leuven, Belgium.
A
A
Van Hecken
M L
ML
Juliano
M
M
Depré
I
I
De Lepeleire
J
J
Arnout
A
A
Dynder
L
L
Wildonger
K J
KJ
Petty
K
K
Gottesdiener
J N
JN
De Hoon
D000293:Adolescent; D000328:Adult; D001241:Aspirin / Q000008:administration & dosage / Q000494:pharmacology*; D001792:Blood Platelets / Q000187:drug effects* / Q000502:physiology; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D013608:Tablets, Enteric-Coated; D013929:Thromboxane B2 / Q000096:biosynthesis / Q000097:blood
D010975:Platelet Aggregation Inhibitors; D013608:Tablets, Enteric-Coated; D013929:Thromboxane B2; D001241:Aspirin