Clinical Review

Background

When you use most topical arthritis products, you are taking a leap of faith, since they typically offer no proof that they actually work to reduce arthritis pain.

Zostrix is different—it has been tested in rigorous clinical studies, involving hundreds of patients and careful procedures to prevent any bias. We don’t ask you to accept our claims on faith; we ask you to look at the evidence. Summarized below are the results of several arthritis and neuralgia studies conducted using Zostrix.

Clinical Reviews: Arthritis
Among topical arthritis pain relievers, Zostrix is unique in that its safety and efficacy have been documented in published, double-blind, placebo-controlled studies. No other topical arthritis pain reliever has been tested as extensively as Zostrix in large, well-controlled clinical studies. This is an important factor that distinguishes Zostrix from all other arthritis pain relievers, including “knock-off” products containing capsaicin—only Zostrix has a vehicle delivery system proven to release the active ingredient capsaicin in a therapeutically effective manner.

The proven effectiveness of Zostrix in treating arthritis pain is one reason why doctors have recommended Zostrix for arthritis pain more than all other topical analgesics combined. Below we briefly review two key studies highlighting the effectiveness of Zostrix cream on relieving arthritis pain. We also provide the study references, so if you wish you can read the published articles in their entirety.

1. Study of Zostrix in Treating Arthritis Pain

Study Description:
113 patients were enrolled in a 12-week, double-blind, vehicle-controlled, randomized, multi-center trial evaluating the clinical safety and efficacy of topically applied Zostrix for the relief of pain associated with osteoarthritis. Subjects were not allowed to use any other pain reliever, whether oral or topical. Each patient randomly received either Zostrix or a placebo cream, four times per day for 12 weeks.

Key Findings:

• Nine out of ten (86%) of patients treated with Zostrix experienced a reduction in pain by week 4.
• Zostrix-treated patients reported an average reduction in pain of 53% by week 4.

Reference:
Altman RD, Aven A, Holmburg CE, et al: Capsaicin cream 0.025% as monotherapy for osteoarthritis: a double-blind study. Semin Arthritis Rheum. 1994; 23(suppl3): 25-33.

2. Study of Zostrix Used With Oral Pain Relievers to Treat Arthritis Pain

Study Description:
101 patients who were already taking oral pain medications for osteoarthritis (OA) and rheumatoid arthritis (RA) enrolled in a 4-week, double-blind, vehicle-controlled, randomized, multi-center trial evaluating the clinical safety and efficacy of topically applied Zostrix for the relief of pain associated with OA and RA. During the study, each subject continued to use a constant baseline dose of oral pain relievers and also applied either Zostrix or a placebo cream, four times per day for four weeks.

Key Findings:

• OA patients reported an average reduction in pain of 21% in week 1 and 33% by week 4 when using Zostrix along with oral pain medications.
• RA patients reported an average reduction in pain of 31% in week 1 and 57% by week 4 when using Zostrix along with oral pain medications.
• The above pain reductions were measured from baseline and thus indicate relief above and beyond that already provided by their existing oral pain medications.
• 96% of the Zostrix-treated patients found that they could better perform acts of daily living such as walking, sitting, and driving, relative to when they used their oral pain medications alone.

Reference:
Deal CL, Schnitzer TJ, Lipstein E, et al. Treatment of arthritis with topical capsaicin: a double-blind trial. Clinical Therapeutics. 1991;13:383-395.
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Clinical Reviews: Neuralgias
There are numerous clinical studies demonstrating the effectiveness of Zostrix in treating certain neuralgias when used as part of a treatment regimen under the supervision of a physician. Below we summarize two studies evaluating Zostrix in the local relief of pain from diabetic neuropathy and post-herpetic neuralgia (pain following shingles). We encourage you to look at these study summaries, but you should not use Zostrix for treating painful neuralgias except after consultation with a professional healthcare provider.

1. Study of Zostrix in Treating Local Pain from Diabetic Neuropathy

Study Description:
277 patients were enrolled in an 8-week, double-blind, vehicle-controlled, randomized, multi-center trial evaluating the clinical safety and efficacy of topically applied Zostrix-HP for the local relief of pain associated with diabetic neuropathy. Each patient applied either Zostrix-HP or a placebo cream, four times per day for eight weeks.

Key Findings:

• Patients treated with Zostrix-HP had significantly less pain than those treated with placebo cream at each of the 2-week, 4-week, 6-week, and 8-week test points.
• Seven of ten patients (69%) treated with Zostrix-HP showed improvement after two weeks of treatment.
• Patients treated with Zostrix-HP had an average decrease in pain of 30% after four weeks and 40% after eight weeks of treatment.
• Patients who used Zostrix-HP were significantly better able to perform routine daily activities such as working, walking, and sleeping than those who did not use Zostrix-HP.

Reference:
The Capsaicin Study Group. Treatment of painful diabetic neuropathy with topical capsaicin: a multicenter, double-blind, vehicle-controlled study. Arch Intern Med. 1991; 151:2225-2229.

The Capsaicin Study Group. Effect of treatment with capsaicin on daily activities of patients with painful diabetic neuropathy. Diabetes Care. 1992;15:159-165.

2. Study of Zostrix in Treating Local Pain from Post-Herpetic Neuralgia

Study Description:
93 patients who had post-herpetic neuralgia (pain after shingles) lasting more than 12 months were enrolled in a double-blind, placebo-controlled, randomized trial evaluating the clinical study and efficacy of Zostrix-HP in treating post-herpetic neuralgia. Each patient applied either Zostrix-HP or a placebo cream, four times per day for six weeks. After the six-week blinded period, 77 patients were followed for up to 2 years in an open-label study of the long-term effectiveness of Zostrix-HP in treating local pain from post-herpetic neuralgia.

Key Findings:

• A significantly larger number of Zostrix-HP patients had reductions in pain relative to those using a placebo cream. At the end of the 6-week period,physician assessments found that 64% of the Zostrix-HP patients had improved, compared to only 25% of the vehicle-treated patients.
• The typical reduction in pain reported by subjects was significantly higher for subjects who used Zostrix-HP. After six weeks, the average reported reduction in pain was 39% for Zostrix-HP users, compared to 6% for those using placebo cream.
• By using Zostrix-HP for up to two years, patients were able to maintain or amplify pain relief in prolonged treatment period.

Reference:
Watson CPN, Tyler KL, Bickers DR, et al. A randomized vehicle-controlled trial of topical capsaicin in the treatment of postherpetic neuralgia. Clinical Therapeutics. 1993; 15:510-526.
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