NATIONAL HARBOR, MD. – Topical diclofenac sodium 1% gel was as well tolerated as placebo, based on data from 1,426 patients with knee osteoarthritis and 783 patients with hand osteoarthritis.
Findings from previous studies have shown that diclofenac sodium 1% gel (DSG) is effective in treating knee and hand osteoarthritis (OA), but safety data were limited, said Dr. John H. Peniston of Feasterville (Pa.) Family Health Clinic.
In this pooled analysis, the researchers reviewed data from patients aged 35 years and older with knee OA and aged 40 years and older with hand OA. The findings were presented in a poster at the annual meeting of the American Academy of Pain Medicine.
In the group with knee OA, 721 patients were randomized to DSG and 705 to a placebo gel. The most common adverse events were application site related; these occurred in 406 (56.3%) of the DSG patients and 340 (48.2%) of the placebo patients. The incidence of gastrointestinal, cardiovascular, hepatic, or renal adverse events (AEs) was similar between the two groups. The only serious AE potentially related to treatment was a deep-vein thrombosis and pulmonary embolism that developed in an 80-year-old woman with multiple cardiovascular–risk factors, the researchers noted. The most common treatment-emergent AE was headache, reported in approximately 15% of patients in each group.
In the group with hand OA, 400 patients were randomized to DSG and 383 to a placebo gel. Application site events were the most common AEs, occurring in 163 (40.8%) of the DSG patients and 139 (36.3%) of the placebo patients. Rates of cardiovascular, gastrointestinal, renal, and hepatic AEs were similar between the groups. Treatment-related gastrointestinal events occurred in two patients in the DSG group and one in the placebo group. None of the cardiovascular or serious AEs in either group were considered treatment-related, the researchers wrote. However, two patients with hand OA in both the active treatment and placebo groups experienced liver-enzyme elevation to three times the upper limit of normal. The most common treatment-emergent AE was headache, reported by 9% of patients in the DSG group and 10% of the placebo group.
"In general, adverse events with diclofenac sodium were mild and resolved without the need for additional treatment, consistent with a favorable tolerability profile," the researchers said.
The clinical trials for DSG were funded by Novartis, and this post hoc analysis was funded by Endo Pharmaceuticals. Dr. Peniston said he had no financial conflicts to disclose, but several study coauthors were employed by either Novartis or Endo.