A paper by authors including Johnson and Kamatani of our company was published as a letter in Arthritis and Rheumatology.

Johnson TA, Kuwabara M, Kamatani N. Xanthine oxidase inhibitor withdrawal syndrome? Arthritis Rheumatol. 2019 Aug 5. doi: 10.1002 / art.41066.
PMID:31379099

By analyzing the published data from the CARES study, we found that mortality was higher after discontinuing gout medications allopurinol and febuxostat than during the administration period. For both drugs, the mortality rates were more than 18 times higher within the first month after discontinuation as compared with during the administration period, and the mortality rate gradually declined in about half a year. We considered that both drugs decreased the mortality rate by the ATP enhancement during the administration, but the beneficial effect was abolished by the discontinuation of the drugs. This phenomenon may be called “withdrawal syndrome”. The results of CARES study revealed the mystery that most of the deaths occurred during the off-drug periods, but we think that our present results, for the first time, solved that mystery.