The present invention provides an ion pair compound of the formula [narcotic]
+
[A]
−
, wherein [narcotic]
+
represents at least one cation of at least one narcotic agent or one or more stereochemical isomers thereof and [A]
−
represents at least one anion of at least one NSAID or one or more stereochemical isomers thereof. An example of the ion pair compound is propoxyphene diclofenate. The ion pair compounds, or their pharmaceutical compositions, are useful in methods of treating a wide variety of conditions that indicate analgesics, anti-inflammatory agents, or both. Under the conditions prescribed for their use, the ion pair compounds exhibit poor or complete insolubility but excellent chemical stability in low pH environments, such as those found in the stomach. The ion pair compounds readily dissolve and dissociate in higher pH environments such as the small intestine to release the constituent narcotic and NSAID.
A salt of a codrug of at least two drug compounds covalently linked to one another via a labile bond to form a single codrug, and methods of use of the codrug salt for the treatment of various medical conditions. The codrug salt may be administered by itself or in the form of a bioerodible or nonbioerodible substance.