Background and Objectives Calcium deposits of the shoulder may persist for many years with resulting pain and impairment of mechanical function. The effects of different treatments vary significantly and do not show consistent and reliable long-term results. Cimetidine decreases calcium levels and improves symptoms in patients with hyperparathyroidism. We evaluated cimetidine as a treatment for chronic calcifying tendinitis of the shoulder in patients who did not respond to conservative treatment.

Methods Cimetidine, 200 mg twice daily, was given orally for 3 months in 16 patients who did not respond to more than 6 months of conservative treatment. We recorded subjective, functional, and radiologic findings at 1 day before, at 2 weeks after, and at 2 and 3 months after the start of cimetidine. We also performed a follow-up study (4 to 24 months).

Results After treatment, peak pain score (visual analogue scale: 0 - 100) decreased significantly from 63 ± 13 to 14 ± 19 (mean ± SD, P < .01) and 10 patients (63%) became pain free. Physical impairment was also significantly improved. Calcium deposits disappeared in 9 patients (56%), decreased in 4 patients (25%), and did not change in 3 patients (19%). Follow-up data showed that improvement of symptoms was sustained. No recurrence or enlargement of calcium deposits was observed. Plasma concentrations of calcium and parathyroid hormone did not change significantly.

Conclusions Our results indicate that cimetidine is effective in treating chronic calcifying tendinitis of the shoulder; however, the mechanism by which cimetidine improves the symptoms is unknown.