Comparative study of the efficacy of zinc acetate hydrate and polaprezinc for zinc deficiency taste disorder

Objective In Japan, polaprezinc (PPZ) and zinc acetate hydrate (ZAH) are the only two zinc replacement drugs that can be administered for taste disorder. The ZAH formulation is expected to be more useful than PPZ because of its higher zinc content. This study was conducted to compare the efficacy and safety of these two drugs and to clarify each of their characteristics. Methods Seventy seven patients with taste disorder as the primary complaint who were examined and treated in the Hokkaido University Hospital. These were divided into two groups with 31 patients treated with PPZ and 46 patients treated with ZAH. The primary endpoint was the rate of improvement in subjective symptoms. Cases were considered to be effective if there was a decrease in the taste disorder VAS of more than 50 % compared to that obtained prior to the administration of zinc. Results There was a significant increase in serum zinc levels in both groups after administration of zinc treatment (ZAH, PPZ: p < 0.001). However, the percentage of patients who improved to normal serum zinc levels and the increase in serum zinc levels/month were significantly higher in the ZAH group than in the PPZ group (p = 0.004, p = 0.035). Conclusions Although improvement in serum zinc levels was shown to be more effective in the ZAH group than the PPZ group after the short treatment period of 3 months, it should be noted that no correlation between the amount of increase in serum zinc levels and the improvement rate in subjective symptoms was shown.