Significance of Kampo medicine in pain clinic “1st International Symposium on Kampo Medicine”

To The Editor In this article, we report from Japan and Germany on the practical application of Kampo therapy for pain in clinical practice and in basic research. Kampo is a traditional Japanese therapeutic medicine that is mostly derived from classical Chinese medicine and was introduced into Japan between the 5th and 6th centuries. Over the years, unique methods for diagnosis, herbal formulas, and therapeutic approaches using Kampo have been developed in Japan. Japanese public insurance coverage of Kampo treatment started in 1961. Permission for medical use of six Kampo extracts was granted in 1967 [1]. Approximately 150 kinds of Kampo medicine are covered by government health insurance, and in general, Kampo therapy became a complementary and alternative medicine that can be easily incorporated into Western medicine. Many countries around the world practice integrative medicine in the form of modern medicine plus alternative and complementary medicine, but only a few, such as Japan, practice integrative medicine in the form of incorporating traditional medicine with modern medicine. The reason for this lies in differences in the licensing of physicians. In China and Korea, there used to be two licenses, one for modern medicine and the other for traditional medicine, but in Japan, the licenses were unified. Therefore, with one license, it is possible to practice integrative medicine, making full use of not only modern medicine but also traditional medicine. Many Japanese pain clinicians use Kampo medicine. Kampo is used for patients who do not respond well to Western medicine, patients with side effects from Western medicine, elderly people, and patients who want to be treated with Kampo medicine. In pain clinic, Kampo medicine is effective for the treatment of headaches (migraine, tension headache, cluster headache), lumbago, post-herpetic neuralgia (PHN), and, especially, sympathetically maintained pain. It has been used for the treatment of acute and chronic pain. On the basis of this background, Hiromichi Yasui classified Kampo treatment into four types. Knowing which type of Kampo treatment is currently being practiced is clinically beneficial to the practitioner because it can clarify the form of Kampo treatment. Type 1 includes Kampo treatment that is better than standard Western medical treatment and is thus used alone. In type 2, the effects of standard Western medical treatment and Kampo treatment are strengthened by using the two in combination. In type 3, the side effects of standard Western medical treatment can be mitigated in combination with Kampo treatment. In type 4, treatment is needed, but standard Western medical treatment cannot be applied. In the setting of clinical practice for pain treatment, we also consider the four types from the viewpoint of integrative medicine [2]. In Japan, basic research on pain (especially neuropathic pain) in Kampo medicine has been active in recent years. Neuropathic pain is refractory to treatment and tends to become chronic, adversely affecting patients’ quality of life (QOL). With the development of chronic pain, both organic and psychosocial factors surrounding pain become more complex, making treatment difficult. Kampo medicine that involves the use of Japanese herbal medicines has numerous pharmacological effects and, therefore, effectively relieves pain by targeting numerous factors surrounding the pain. Integrative medicine, which combines Western medicinal science and Kampo medicine, could be an effective strategy in the modern treatment of pain; however, it is important to elucidate the mechanisms underlying the effects of herbal medicine. Despite challenges, there has been recent progress in elucidating the therapeutic mechanisms of Japanese herbal medicines and crude drugs, including goshajinkigan, yokukansan, and aconite root [3, 4, 5]. Elucidation of the analgesic mechanism of action of herbal medicines could clarify the position of Kampo treatment in modern medicine, establish integrative medicine combining Western medicinal science and Kampo medicine, and develop novel therapeutic strategies using Kampo treatment for effective treatment of neuropathic pain. How about outside of Japan? Herbal medicine has a longstanding tradition in Germany. Plant-based drugs have the status of well-controlled registered pharmacyonly drugs. More than two-thirds of the German population regularly take herbal medicinal products, confirming the high acceptance of phytotherapy in Germany. At the same time, herbal traditions from other parts of the world have gained increasing attention. Japanese traditional herbal medicine (Kampo medicine) Received: 27 May 2022 Revised: 27 June 2022 Accepted: 6 July 2022