Charge-independent effects of drugs on erythrocyte morphology

The effects of chlorpromazine, tetracaine, indomethacin, barbitone and benzyl alcohol on human erythrocyte shape have been examined. Cationic and anionic drugs produced stomatocytes and echinocytes respectively as expected for cells in isotonic saline. Particular attention has been directed here to some features of drug induced morphology change which are independent of the charge of the drug. It was found that (i) the direction (increase or decrease) of the extent of morphological change as temperature was increased from 20 to 37 degrees, (ii) the exposure time for maximum shape change (0-2 min), and (iii) the time course of cell morphology (0-30 min) were different for similarly charged drugs. The influence of low concentrations of the drugs on the thermal fragmentation patterns of the cells has been determined. A single index has been derived which allows comparison of the morphological effects of cationic and anionic drugs. It was concluded that, while the type (stomatocyte or echinocyte) of shape change observed was dependent on the charge of the drug, cell morphology at drug concentrations high enough to produce marked shape change at 37 degrees was strongly influenced by charge independent drug-specific effects.