Drug-Induced Muscle Contracture

1. Emergence of the disease through injections

Drug-Induced Muscle Contracture refers to movement disorders—such as difficulty walking—caused by muscular contracture, especially of the quadriceps femoris, following intramuscular injections administered to children. At the time, injections were widely believed to be more effective and fast-acting than oral medications, and even minor illnesses such as the common cold were often treated by injection. Furthermore, the profit-oriented operation of Japan’s universal health insurance system, launched in 1961, and aggressive marketing by pharmaceutical companies encouraged the overuse of injections, even when medically unnecessary. Warnings against “reckless injections” had already been issued as early as the 1940s, yet no concrete countermeasures or identification of the cause followed. By the mid-1960s, clusters of children with sudden walking difficulty appeared in Shizuoka and Fukui Prefectures and in Nagoya City and were dubbed “Izumida disease” and “Imadate disease” after the local areas. A major outbreak occurred in southern Yamanashi Prefecture in 1973 and became a nationwide issue through media coverage. As the cause was initially unknown, the condition was called “stiff-knee disease of infancy” and was suspected to be hereditary, a rare illness, or even a local environmental factor. Doctors’ investigations later confirmed intramuscular injection as the true cause.

2. Formation of victims’ organizations and start of litigation

The Yamanashi cluster prompted parents’ associations and support groups to organize, while members of the National Diet from Yamanashi raised the issue in both houses of parliament. At a House of Representatives hearing, Lecturer Akimasa Takahashi (University of Tokyo) testified that “the mass occurrence of quadriceps femoris contracture is caused by intramuscular injection,” prompting the former Ministry of Health and Welfare (MHW) to conduct an investigation. Combining results from the official survey and from an independent “voluntary health-check team” of doctors, the number of victims was estimated at approximately 20,000. Government response, however, remained slow. The Japan Medical Association merely issued a notice urging restraint in pediatric injections. To seek state-level relief, parents of patients with Drug-Induced Muscle Contracture formed a nationwide organization in 1974. Some parents also filed lawsuits against the state, pharmaceutical companies that sold the injectable solutions, and the doctors or medical associations that administered them. These suits evolved into collective litigation nationwide—the only drug-induced suffering case in Japan to name a medical association as a defendant. During the struggle, a 1977 MHW research subcommittee on the “Prevention of Muscle Contracture” proposed, “constitutional factors may be involved in the pathogenesis,” introducing the “constitutional-cause theory.” By suggesting that contracture might arise from individual predisposition instead of reckless injection, this government-backed theory risked blurring the defendants’ responsibility and influenced the court proceedings. In the first trials across local courts, pharmaceutical companies were found liable, while the state was not held responsible on the grounds that it “could not have foreseen” the occurrence of Drug-Induced Contracture. Plaintiffs appealed to seek state responsibility, but with numerous defendants—government agencies, pharmaceutical companies, and doctors—the trials dragged on for many years. More than a decade after the first filings, most cases concluded through settlement instead of judgment, leaving the government’s responsibility unacknowledged.

3. Efforts after the conclusion of litigation

Following the conclusion of regional trials, the nationwide organization formed to protect children from Drug-Induced Muscle Contracture was dissolved. However, victims continued to face physical and psychological suffering, as well as new life challenges, creating the need for an ongoing support organization. Consequently, victims’ associations in Kyoto and Shiga Prefectures continued their activities independently. As members later became dispersed across Japan, the group renamed itself the National Association of Drug-Induced Muscle Contracture. Today, it conducts educational and advocacy activities nationwide, supports aging victims facing increased disability, and continues negotiations with government authorities for sustained assistance.

References

1. The Pharmaceutical and Medical Device Regulatory Science Society of Japan (2012), 『知っておきたい薬害の教訓――再発防止を願う被害者からの声』YAKUJI NIPPO, (ISBN 4840812136).
2. 山梨県注射による筋短縮症児救済対策会議 (1994),『取りのぞこう つまずいた石』THE YAMANASHI NICHINICHI SHIMBUN.