Duration of morning stiffness in rheumatic patients after medication with enteric-coated and plain naproxen tablets.

Twenty-nine adult rheumatic patients who were taking 500 mg naproxen at bedtime and had a certain degree of morning stiffness despite this medication took part in a randomized double-blind cross-over study in which the duration of morning stiffness after evening doses of 500 mg enteric-coated naproxen tablets was compared with that after identical doses of plain naproxen tablets. The duration of morning stiffness was significantly shorter after taking enteric-coated tablets (p less than 0.01), and the mean plasma naproxen morning concentration was 34% higher (p = 0.01). Since the results were unambiguous in such a small group of patients, they are judged to be of considerable clinical value.