Heparin-Lidocaine Noninteraction

Cationic lidocaine (lignocaine) hydrochloride is commonly assumed to be incompatible with anionic sodium heparin.The possibility of interac- 

Clinical investigations on hemodialysis patients receiving both drugs did not detect any interaction. 

Because the two drugs may be indicated concurrently, it is important to confirm or deny significant interaction. As usual in the clinical situation, an immediate definite decision is required— what to do for this patient now. To complicate the regimen or to deny optimum drug therapy because of a spurious interaction is to do considerable harm and to do this harm repetitively. 

Metachromasia, from meta, a change in the kind of, and chroma, color, refers to the qualitative change which occurs in the color of certain dyes when they interact with other substances. The term was originally applied by Paul Ehrlich to the phenomenon of color change when a dye is adsorbed onto a substrate. Thus, cartilege and other mucopolysaccharide-containing tissues are stained red by toluidine blue. Similarly, Hartley observed that when bromophenol blue solution is added to cetrimide solution the color changes from purplish blue to clear blue. 

---