Stavudine is a nucleoside reverse transcriptase inhibitor (NRTI) with activity against Human Immunodeficiency Virus Type 1 (HIV-1). Stavudine is phosphorylated to active metabolites that compete for incorporation into viral DNA. They inhibit the HIV reverse transcriptase enzyme competitively and act as a chain terminator of DNA synthesis. The lack of a 3'-OH group in the incorporated nucleoside analogue prevents the formation of the 5' to 3' phosphodiester linkage essential for DNA chain elongation, and therefore, the viral DNA growth is terminated. Stavudine inhibits the activity of HIV-1 reverse transcriptase (RT) both by competing with the natural substrate dGTP and by its incorporation into viral DNA. Stavudine is used for the treatment of human immunovirus (HIV) infections. Stavudine is sold under the brand name Zerit among others.

Thymidine is a water-soluble pyrimidine deoxynucleoside and potent thymidine kinase substrate. Thymidine is known to be converted to dTTP and utilized for DNA synthesis. It is also known that thymidine is converted by catabolic enzymes to several end products. Excess thymidine results in high levels of dTTP, which exerts a regulatory feedback inhibition in the nucleotide biosynthesis pathways leading to DNA synthesis. This property of thymidine is used when it is given in high doses to patients with solid tumors. Thymidine is being tested in Phase II of clinical trials for the treatment of cancer and 5'-Nucleotidase Syndrome.

Sodium is the primary cation (positive ion) in extracellular fluids in animals and humans. Sodium ions are necessary for regulation of blood and body fluids, transmission of nerve impulses, heart activity, and certain metabolic functions. Physiologically, it exists as an ion in the body. Sodium is needed by animals, which maintain high concentrations in their blood and extracellular fluids, but the ion is not needed by plants. The human requirement for sodium in the diet is less than 500 mg per day, which is typically less than a tenth as much as many diets "seasoned to taste. " Most people consume far more sodium than is physiologically needed. For certain people with salt-sensitive blood pressure, this extra intake may cause a negative effect on health.