Ms Satp Us History Study Guide - Allopurinol, sold under the brand name Zyloprim among others, is a medication used to decrease high blood uric acid levels. It is specifically used to prevent gout, prevent specific types of kidney stones and for the high uric acid levels that can occur with chemotherapy. It is taken by mouth or injected into a vein. Common side effects when used by mouth include itchiness and rash.. Resources. Study to shew thyself approved unto God, a workman that needeth not to be ashamed, rightly dividing the word of truth. 2 Tim 2:15 (KJV). Caffeine is a central nervous system (CNS) stimulant of the methylxanthine class. It is the world's most widely consumed psychoactive drug.Unlike many other psychoactive substances, it is legal and unregulated in nearly all parts of the world..