An observer-blind comparative clinical study was carried out in 108 patients presenting with
ankle sprains at an Accident and Emergency department. The efficacy and tolerability of
diclofenac potassium (50 mg 3-times daily) was compared with that of
piroxicam (20 mg once daily), and placebo. Patients were allocated at random to receive one or other of the three treatments for 7 days. There were 36 patients in each group. The
analgesic and anti-inflammatory effects of treatment were assessed from volumetric measurements of
inflammation at the injured ankle, tenderness,
pain on passive movement, severity of the joint lesion, severity of
pain at rest and on movement. The overall reductions in
pain and
inflammation were assessed at the end of the study. The results in patients treated with
diclofenac potassium were significantly better than those in patients treated with
piroxicam with respect to the improvement in
pain on walking and the overall reduction in
pain and
inflammation, and both active treatments were superior to placebo. There was no significant difference between
diclofenac potassium and
piroxicam with respect to
inflammation measured by volumetry, tenderness, and severity of
pain at rest, but both active treatments were consistently superior to placebo. No serious adverse effects were reported. All the patients treated with
diclofenac potassium and all those treated with
piroxicam said that they would be willing to take the
drug again; this was the case with only 27.8% of the placebo group.
Diclofenac potassium can be considered an effective treatment for acute
ankle sprains with a rapid onset of
analgesic and anti-inflammatory action and good tolerability.