Pain Perception following Subcutaneous Injections of Citrate-Buffered and Phosphate-Buffered Epoetin Alpha

Subcutaneous injection of citrate-buffered epoetin alpha (EPO-α) causes pain. Substitution of citrate buffer with a phosphate buffer in the EPO-α resulted in a significant reduction in duration and severity of pain. It is possible that sodium citrate which is present in the EPO-α may be the agent that causes discomfort in the patients.