Uridine 5'-triphosphate (UTP, INS316) is a naturally occurring agonist for P2Y(2) receptors on the apical surface of ciliated respiratory epithelium. INS316, being developed by Inspire Pharmaceuticals, is a short-acting, aerosolized uridine 5-triphosphate (UTP) solution used as a diagnostic aid for lung cancer. INS316 appears to improve sputum expectoration mediated through the P2Y2 receptor, a nucleotide receptor expressed in human airway epithelial cells and some other tissues. UTP binding to the P2Y2 receptor triggers signal transduction that leads to chloride ion secretion, thereby resulting in mucociliary clearance of airway. UTP stimulates salt and water transport and cilia beat frequency in human airway epithelium in vitro. Single, inhaled doses of UTP stimulate mucociliary clearance in conscious, intubated sheep and in patients with mild chronic bronchitis (smokers and former smokers), suggesting that UTP may be useful for obtaining deep-lung sputum specimens suitable for diagnostic purposes. A single dose of INS316 safely improves the ability of patients with mild chronic bronchitis to expectorate a deep-lung sputum specimen suitable for cytologic evaluation.

Broxuridine (5-Bromo-2-deoxyuridine, BrdU) is a thymidine analogue that is incorporated into replicating DNA. BrdU taken up by cells is phosphorylated and incorporated into DNA in place of dT. Although originally designed as a chemotherapeutic agent, sublethal concentrations of BrdU have long been known to alter the growth and phenotype of a wide range of cell types. The most popular use of BrdU is as a tracer of DNA synthesis. The other well-known use of BrdU is as a DNA photosensitizer. BrdU substitution of dT in DNA sensitizes it to near-UV light, and cells with BrdU-substituted DNA cannot survive after exposure to near-UV light. BUdR has side effects on cell functions. Cell growth can be inhibited, normal development of differentiating systems be perturbed, activities of specific enzymes be reduced. Mutagenic effects of BUdR are interpreted as reflections of a mispairing of BUdR in its rare enol form. Effects of BUdR which can be reversed by addition of thymidine are not likely to be mutagenic. As another mechanism of action of BUdR has been suggested that incorporation of BUdR into DNA alters the pattern of transcription.

Diquafosol, a dinucleotide Up4U, is an agonist for purinergic P2Y2 receptor. Diquafosol stimulated water and mucin secretion by acting on P2Y2 receptors on the conjunctival epithelial and goblet cell membrane and elevating intracellular calcium ion concentrations. The Japanese Ministry of Health, Labour and Welfare granted approval for DIQUAS Ophthalmic Solution 3% (diquafosol tetrasodium) for the treatment of dry eye.

Doxifluridine is a 5-fluorouracil prodrug that is being tested for the treatment of cancer. The cleavage into 5-fluorouracil occurs enzymatically via a nucleoside phosphorylase. Thus, doxifluridine is not active by itself and its antitumor activity is related to its metabolic conversion into 5-fluorouracil. Doxifluridine has neurotoxic adverse effects.

Edoxudine (5-ethyl-2'-deoxyuridine), an antiviral drug, has been clinically studied against the recurrent genital herpes.