Abstract: The present invention relates to P1-(cytidine 5′-)-P-(uridine 5′-)tetraphosphates and its salts, esters and amides, and formulations thereof which are highly stable and selective agonists of the P2Y2 and/or P2Y4 purinergic receptor. The compounds of the invention are useful in the treatment of chronic obstructive pulmonary diseases such as chronic bronchitis, primary ciliary dyskinesia, cystic fibrosis, as well as prevention of pneumonia due to immobility, and the induction of sputum and its expectoration. Furthermore, because of their general ability to clear retained mucus secretions and stimulate ciliary beat frequency, the compounds of the present invention are also useful in the treatment of sinusitis and otitis media.