Background and purpose
Osteoarthritis is the most common type of arthritis, and knee osteoarthritis is one of the most important types, which causes symptoms such as pain and stiffness of the knee, followed by a weakening of physical performance and a decrease in quality of life. Among the complementary treatments that are of interest are new and optimal drugs that can reduce the pain and discomfort of patients with fewer side effects. We aim to investigate the effect of doxepin cream in reducing pain in patients with knee osteoarthritis.
Methods
In this double-blind clinical trial, 60 patients with knee osteoarthritis were selected and randomly divided into 3 groups of 20 people. The first group used placebo cream 2 times a day, the second group used 5% doxepin cream 2 times a day, and the third group used diclofenac 1% topical gel 2 times a day. All three groups used 250–500 mg naproxen tablets orally daily. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Visual Analogue Scale (VAS) questionnaires were checked at the beginning of the study and six weeks after the start of treatment. Improvement of physical function and reduction of pain is considered as a response to treatment.
Results
This study showed that after the doxepin intervention, in second group there was a significant difference in knee pain (P < 0.005), dryness during the day (P < 0.05), morning dryness (P < 0.05), and physical performance (P < 0.05) between the groups. In the two groups receiving doxepin cream and diclofenac gel, there was a significant reduction in symptoms (pain and stiffness of the knee) and an improvement in physical performance.
Conclusion
The topical form of doxepin, which was prepared as a cream, reduced knee pain, morning dryness, and dryness during the day and improved the physical performance of patients with primary knee osteoarthritis. It seems that the reduction of patient symptoms is due to the inhibitory effects on NMDA(N-methyl-D-aspartate) receptors, as well as the inhibitory effects on noradrenaline and 5-hydroxytryptamine reabsorption, as well as the inhibition of sodium voltage channels.