Ritalinic acid in urine: Impact of age and dose.
Pract Lab Med 2021;
27:e00258. [PMID:
34754895 PMCID:
PMC8561308 DOI:
10.1016/j.plabm.2021.e00258]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 10/12/2021] [Accepted: 10/20/2021] [Indexed: 11/28/2022] Open
Abstract
Objectives
The objective of this work was to study the results of urine drug testing for ritalinic acid (RA), the major urinary metabolite of methylphenidate (MP) (e.g., Ritalin®). The impact of age from 4 to 65 years old and older on median levels of RA was investigated as well as potential variations in pH, specific gravity and creatinine content of the patient urine samples.
Design and Methods
Samples from patients who were 1) prescribed MP and found to be positive for RA, 2) prescribed MP but found to be negative for RA and 3) not prescribed MP but tested positive for RA were examined by liquid chromatography – mass spectrometry/mass spectrometry (LC-MS/MS) for RA concentration. The levels of RA were examined for median and average levels and further normalized and transformed to reveal a near gaussian distribution.
Results
Over 20,000 samples from patients who were prescribed MP were examined for this work. Analysis of these data for a subset of patients prescribed MP and testing positive for RA revealed statistically different median values of RA for school age patients of 6 years old through 17 years old from adult patients 18 through 64 years old. Another 6751 samples were positive for RA without a prescription but were not included in the overall assessment of these data.
Conclusions
While not clear as to the reason, these data indicate that school age children under the age of 18 have much higher levels of RA than adult patients. These results can be used to estimate “normal” levels of RA in these chronically dosed populations.
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