title: Estimating compliance with diuretic therapy: urinary hydrochlorothiazide-creatinine ratios in normal subjects.
abstract: We gave 21 healthy young men 100 mg of hydrochlorothiazide daily to determine whether or not urinary detection of the drug was feasible as a measure of compliance on a standard antihypertensive regimen. All subjects took the drug daily for 6 days, after which they were divided into four groups with differing patterns of medication administration. Urine hydrochlorothiazide and creatinine measurements were obtained to validate the urinary hydrochlorothiazide-creatinine ratio (UHCR) as an accurate quantitative index of compliance. The subjects achieved a constant level of UHCR of 13 +/- 3.0 within 48 hours of hydrochlorothiazide administration. The UHCR levels decreased to 5.0 +/- 0.8 48 hours after discontinuation of the drug (p less than 0.001). UHCR values in the range of  13 +/- 6 indicate that the subject has ingested hydrochlorothiazide 24 hours previously. The UHCR is a potentially useful means of assessing compliance in hypertensive patients taking hydrochlorothiazide.
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000187:drug effects; D003404:Creatinine / Q000652:urine; D004232:Diuretics; D006207:Half-Life; D006801:Humans; D006852:Hydrochlorothiazide / Q000627:therapeutic use* / Q000652:urine; D006973:Hypertension / Q000188:drug therapy*; D008297:Male; D010349:Patient Compliance; D013997:Time Factors
chemical_list: D004232:Diuretics; D006852:Hydrochlorothiazide; D003404:Creatinine