title: Guaifenesin- and ephedrine-induced stones.
abstract: OBJECTIVE
  We report a new type of drug-induced stone that is caused by overconsumption of preparations containing guaifenesin and ephedrine.
  
  
  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.
authors.affiliation: Department of Urology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157-1094, USA. dassimos@wfubmc.edu
authors.forename: D G
authors.initials: DG
authors.lastname: Assimos
authors.forename: P
authors.initials: P
authors.lastname: Langenstroer
authors.forename: R F
authors.initials: RF
authors.lastname: Leinbach
authors.forename: N S
authors.initials: NS
authors.lastname: Mandel
authors.forename: J M
authors.initials: JM
authors.lastname: Stern
authors.forename: R P
authors.initials: RP
authors.lastname: Holmes
mesh_terms: D000328:Adult; D002851:Chromatography, High Pressure Liquid; D003461:Crystallography; D004809:Ephedrine / Q000009:adverse effects* / Q000032:analysis / Q000652:urine; D005260:Female; D005583:Fourier Analysis; D006140:Guaifenesin / Q000009:adverse effects* / Q000032:analysis; D006801:Humans; D007668:Kidney / Q000000981:diagnostic imaging; D007669:Kidney Calculi / Q000139:chemically induced* / Q000737:chemistry / Q000000981:diagnostic imaging / Q000652:urine; D008297:Male; D008875:Middle Aged; D004366:Nonprescription Drugs / Q000009:adverse effects*; D019265:Spectroscopy, Near-Infrared; D014054:Tomography; D014057:Tomography, X-Ray Computed
chemical_list: D004366:Nonprescription Drugs; D006140:Guaifenesin; D004809:Ephedrine