Skin Patch for Knee Osteoarthritis Pain?
Lidoderm Patch Could Help, Says Study by Drug's Maker
April 1, 2005 - A skin patch called Lidoderm may help ease pain caused by knee osteoarthritis, giving patients an alternative to the drug Celebrex.
Celebrex is a Cox-2 inhibitor -- a class of drugs that has drawn attention for possible heart attack and stroke risks. In February, an FDA expert panel recommended that remain on the market despite this risk. Official word from the FDA is expected in the next few weeks.
Recent developments regarding these drugs have left many patients concerned about what arthritis drugs are safe for them to take.
Osteoarthritis is the most common type of arthritis. It involves the gradual breakdown of cartilage in joints. Knee osteoarthritis can be painful and even disabling.
The Lidoderm patch isn't approved for knee osteoarthritis pain. It's only been approved for treating pain from postherpetic neuralgia. That's a chronic condition resulting from nerve damage caused by shingles.
Lidoderm Takes On Celebrex
Lidoderm's maker, Endo Pharmaceuticals, sponsored a comparison of Celebrex and Lidoderm in knee osteoarthritis patients. The findings were presented at the American Pain Society's annual meeting.
Originally, the researchers planned to enroll 200 patients. But when Cox-2 drugs became controversial last fall, they stopped adding new patients. That left 143 patients, all of whom had knee osteoarthritis pain.
First, the patients stopped taking all pain medications, as well as the After a week or two, they were randomly assigned to take Celebrex or use the Lidoderm patch for 12 weeks.
The active ingredient in the Lidoderm patch is the pain-numbing medication lidocaine. The patch is applied once daily.
Results were based on patient's ratings of their knee osteoarthritis pain. After six weeks, 62% of the Celebrex group and 54% of the Lidoderm group reported at least a 30% improvement in the average daily intensity of their knee pain. By the 12th week, the numbers had risen to about 71% of each group.
A pain improvement of 30% or greater is considered scientifically meaningful.
Both treatments were well tolerated. Side effects were reported in about 11% of both groups. Three Lidoderm patients dropped out because of side effects; the most common side effects were itchiness or redness at the patch site. No Celebrex patients quit because of side effects.