Pickens CL. Milliron AR. Fussner AL. Dversdall BC. Langenstroer P.
Ferguson S. Fu X. Schmitz FJ. Poole EC.
UroSciences Group, UroCor, Inc., Oklahoma City, Oklahoma 73104, USA.
Abuse of guaifenesin-containing medications generates an excess of a carboxylate salt of beta-(2-methoxyphenoxy)-lactic acid, a guaifenesin metabolite, and results in urolithiasis.
Urology. 54(1):23-7, 1999 Jul.
OBJECTIVES: Several urinary calculi were submitted to our institution for compositional analysis. The typical techniques of analysis, polarized light microscopy, electron microprobe analysis, and infrared spectroscopy proved inadequate for a definitive identification. As a result, a more detailed organic analysis was conducted to determine the exact chemical structure of the material.
METHODS: Infrared spectroscopy and mass spectrometric analysis were carried out on the solid material, providing information concerning the functional groups and the molecular mass of the organic constituent and its components. The stone was solubilized in deuterated solvents and analyzed by nuclear magnetic resonance spectroscopy, which resulted in a definitive chemical structure.
RESULTS: The spectroscopic analysis indicated that the stones were composed of a calcium salt of beta-(2-methoxyphenoxy)-lactic acid, a metabolite of the pharmaceutical guaifenesin, which is used as an expectorant.
CONCLUSIONS: Guaifenesin, an expectorant common in over-the-counter cold and allergy remedies, can cause urolithiasis if taken in excess. Discussions with physicians and their patients confirmed that most patients admitted to taking large doses of guaifenesin-containing medications.
Assimos DG. Langenstroer P. Leinbach RF. Mandel NS. Stern JM. Holmes RP.
Department of Urology, Wake Forest University School of Medicine,
Winston-Salem, North Carolina 27157-1094, USA. email@example.com
Guaifenesin- and ephedrine-induced stones.
Journal of Endourology. 13(9):665-7, 1999 Nov.
PURPOSE: We report a new type of drug-induced stone that is caused by overconsumption of preparations containing guaifenesin and ephedrine.
MATERIALS AND METHODS: Clinical and stone analysis data from the Molecular Structure Laboratory at the Veterans Affairs Medical Center in Milwaukee, Wisconsin, were reviewed. Stone analysis was performed by Fourier transform infrared spectroscopy, high-resolution X-ray crystallographic powder diffraction, or both. The urine and stone material from one of the subjects were analyzed with high-performance liquid chromatography.
RESULTS: Stone analysis from seven patients demonstrated metabolites of guaifenesin. High-performance liquid chromatography revealed that the stone and urine from one subject had a high content of guaifenesin metabolites and a small amount of ephedrine. Demographic data were available on five patients. Three had a history of alcohol or drug dependency. All were consuming over-the-counter preparations containing
ephedrine and guaifenesin. Four admitted to taking excessive quantities of these agents, mainly as a stimulant. Hypocitraturia was identified in two individuals subjected to urinary metabolic testing. These stones are radiolucent on standard X-ray imaging but can be demonstrated on unenhanced CT. Shockwave lithotripsy was performed in two patients, and the calculi fragmented easily.
CONCLUSIONS: Individuals consuming large quantities of preparations containing ephedrine and guaifenesin may be at
risk to develop stones derived mainly from metabolites of guaifenesin and small quantities of ephedrine. These patients may be prone to drug or alcohol dependency.