Table 1.

Comparison of NSAIDs and acetaminophen concentrations incubated with leukocytes to serum concentrations at usual therapeutic dosage and to 50% inhibitory concentrations (IC50) of cyclooxygenase-1 and -2.

Drug	Concentrations
	Tested*		In serum**	IC50***
	mg/mL	μM	μM	COX-1	COX-2
ASA	0.01–0.1–1	31–310–3100	111	4.45	13.88
Diclofenac	0.0013–0.013–0.13	4.2–42.2–422	6.1	0.26	0.01
Ketoprofen	0.025–0.25–2.5	98.3–983–9830	9.4	0.11	0.88
Celecoxib	0.005–0.05–0.5	13.1–131–1310	1.6	82	6.8
Acetaminophen	0.01–0.1–1	66.1–661–6610	117	113.7	25.8

*Each NSAID and and acetaminophen (APAP) were tested at three ten-fold serial dilutions.

**Serum concentrations at usual therapeutic dosage.

***Concentration of drug that inhibited 50% of COX-1 in platelets or COX-2 in monocytes [15–17].