IOTHIOURACIL, in a form of sodium salt, was used as an antithyroid agent in the treatment of hyperthyroidism. It is selectively incorporated into the melanin pigment of melanomas during biosynthesis by serving as false melanin precursors. Radiolabelled (125I) IOTHIOURACIL may be used as a radiopharmaceutical for diagnosis and therapy of melanotic melanomas.

Orotic acid is a minor dietary constituent. Historically it was believed to be part of the vitamin B complex and was called vitamin B13, but it is now known that it is not a vitamin and is synthesized in the body, where it arises as an intermediate in the pathway for the synthesis of pyrimidine nucleotides. Orotic acid is converted to UMP by UMP synthase, a multifunctional protein with both orotate phosphoribosyl transferase and orotidylate decarboxylase activity. The most frequently observed inborn error of pyrimidine nucleotide synthesis is a mutation of the multifunctional protein UMP synthase. As a result, plasma orotic acid accumulates to high concentrations, and increased quantities appear in the urine. Orotic acid levels are elevated in the urea cycle defects ornithine transcarbamylase (OTC) deficiency, citrullinemia and argininosuccinic acidemia, as well as the mitochondrial transport disorder hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome. Orotic acid is also elevated in hereditary orotic aciduria, or uridine monophosphate synthase deficiency, an autosomal recessive disorder characterized by megaloblastic anemia and crystalluria. In addition, orotic acid in combination with leflunomide is in the phase II of clinical trial to evaluate the clinical efficacy and safety of a combination in kidney transplant patients with high levels of Polyoma BK viruria for the purpose of preventing polyoma BK viremia and nephropathy, that could lead to kidney transplant loss from viral damage, acute rejection or both.

Mechlorethamine Oxide was approved by the FDA in 1949 for the treatment of hematologic malignancies, alkylating agents are the oldest class of anticancer agents. A biologic alkylating agent exerts its cytotoxic effects by forming DNA adducts and DNA interstrand crosslinks, thereby inhibiting rapidly proliferating cells. Mechlorethamine Oxide is an antineoplastic agent used to treat Hodgkin desease and Lymphoma. Known under the brand names of Mustargen and Valchlor in USA. The FDA granted marketing approval for the orphan drug Valchlor (mechlorethamine) gel on August 23, 2013 for the topical treatment of stage IA and IB mycosis fungoides-type cutaneous T-cell lymphoma (CTCL) in patients who have received prior skin-directed therapy. Each tube of Valchlor contains 0.016% of mechlorethamine which is equivalent to 0.02% mechlorethamine HCL.