The stability of lidocaine hydrochloride in six commonly used large-volume parenterals when stored for 14 days and the visual compatibility of lidocaine hydrochloride in admixtures with eight frequently used drugs were studied. Lidocaine hydrochloride admixtures of 2 mg/ml were prepared in both glass and plastic containers of 5% dextrose injection, 0.9% sodium chloride injection, lactated Ringer's injection, 5% dextrose and lactated Ringer's injection, 0.45% sodium chloride injection (plastic container only), and 0.45% sodium chloride and 5% dextrose injection. The admixtures were examined visually and stored for 14 days at 25 +/- 0.5 degrees C under fluorescent light. Lidocaine hydrochloride concentrations were determined spectrophotometrically at times 0, 0.25, 1, 3, 8, and 24 hours, and at 24-hour intervals thereafter. Spectrophotometric assays were confirmed with high-pressure liquid chromatography. Admixtures of lidocaine hydrochloride were prepared with aminophylline, bretylium tosylate, calcium gluconate, digoxin, dopamine hydrochloride, regular insulin, phenytoin sodium, and procainamide hydrochloride in 5% dextrose injection, 0.9% sodium chloride injection, and lactated Ringer's injection. The admixtures were examined visually for 24 hours. Admixtures of lidocaine hydrochloride were stable for 14 days. All admixtures of lidocaine hydrochloride with other drugs were visually compatible except those containing phenytoin sodium. It is concluded that lidocaine hydrochloride is stable in the solutions studied for 14 days at 25 degrees C and visually compatible for 24 hours in admixtures containing all drugs studied except phenytoin sodium.