Aspirin helps by inhibiting platelets. Only a tiny amount is needed to inhibit all the platelets in the bloodstream; in fact, small amounts are better than high doses. But since the clot grows minute by minute, time is of the essence.
To find out how aspirin works fastest, researchers in Texas asked 12 volunteers to take a standard 325-mg dose of aspirin in three different ways: by swallowing a tablet with 4 ounces of water, by chewing the tablet for 30 seconds before swallowing it, or by drinking 4 ounces of water with Alka-Seltzer. Each subject tried all three methods on an empty stomach on different days. The scientists monitored blood levels of aspirin and its active ingredient, salicylate, at frequent intervals, and they also measured thromboxane B2 (TxB2), an indicator of platelet activation that drops as platelets are inhibited.
By all three measurements, chewed aspirin worked fastest. It needed only five minutes to reduce TxB2 concentrations by 50%; the Alka-Seltzer took almost 8 minutes, and the swallowed tablet took 12 minutes. Similarly, it took 14 minutes for the chewed tablet to produce maximal platelet inhibition; it took Alka-Seltzer 16 minutes and the swallowed tablet 26 minutes (see graph below).
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