Risperidone

CPT: 80342
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Test Details

Synonyms

  • Risperdal®
  • Risperdal® Consta®

Use

Monitor drug levels for optimal therapy

Limitations

This test was developed and its performance characteristics determined by LabCorp. It has not been cleared or approved by the Food and Drug Administration.

Methodology

Liquid chromatography/tandem mass spectrometry (LC/MS-MS)

Reference Interval

20−60 ng/mL

Additional Information

Risperidone is an antipsychotic agent belonging to the benzisoxazole derivatives class. The mechanism of action is unknown; however, antipsychotic activity may be mediated through a combination of dopamine (D2) and serotonic (5HT2) antagonism. Risperidone is well absorbed by the gut. It is extensively metabolized in the liver to a major active metabolite, 9-hydroxyrisperidone, which appears approximately equieffective with risperidone with respect to receptor binding activity. Consequently, the clinical effect of the drug likely results from the combined concentrations of risperidone and 9-OH-risperidone. The pharmacokinetics for the sum of the two, after single and multiple doses, were similar in both rapid and slow metabolizers, with an overall mean elimination half-life of about 20 hours. Steady-state concentrations are reached in five to six days. The plasma protein binding of risperidone and 9-OH-risperidone is about 90% and 77%, respectively. It has been reported that dosing with long-acting risperidone every two weeks produced lower peak levels than oral dosing, while trough concentrations did not differ between the two routes of administration.1 Chronic administration of carbamazepine with risperidone may increase the clearance of risperidone; whereas, chronic administration of clozapine with risperidone may decrease the clearance of risperidone. The primary side effects noted with risperidone are the extrapyramidal symptoms, such as spasmodic, intermittent contraction of facial, neck, or back muscles, but the incidence of these side effects is lower compared with other neuroleptic agents.

Specimen Requirements

Specimen

Serum

Volume

3 mL

Minimum Volume

1.1 mL

Container

Red-top tube. Do not use a gel-barrier tube. The use of gel-barrier tubes is not recommended due to slow absorption of the drug by the gel. Depending on the specimen volume and storage time, the decrease in drug level due to absorption may be clinically significant.

Collection

Collect specimen just prior to the next dose (trough level).

Storage Instructions

Maintain specimen at room temperature.

Stability Requirements

Temperature

Period

Room temperature

14 days

Refrigerated

14 days

Frozen

14 days

Freeze/thaw cycles

Stable x3

Causes for Rejection

Gel-barrier tube

Clinical Information

Footnotes

1. Eerdekens M, Van Hove I, Remmerie B, et al. Pharmacokinetics and tolerability of long-acting risperidone in schizophrenia. Schizophr Res. 2004 Sep 1; 70(1):91-100. 15246468

References

Castberg I, Spigset O. Serum concentrations of risperidone and 9-hydroxyrisperidone after administration of the long-acting injectable form of risperidone evidence from a routine therapeutic drug monitoring service. Ther Drug Monit. 2005 Feb; 27(1):103-106. 15665755
Raedler TJ, Schreiner A, Naber D, Wiedemann K. Risperidone in the treatment of acute schizophrenia. J Clin Psychopharmacol. 2004 Jun; 24(3):335-338. 15118488

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
716563 Risperidone (Risperdal(R)), S 716564 Risperidone, Serum ng/mL 9393-0
716563 Risperidone (Risperdal(R)), S 716565 9-OH-Risperidone, Serum ng/mL 9383-1
716563 Risperidone (Risperdal(R)), S 716566 Total (Risp+9-OH) ng/mL 9394-8

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The LOINC® codes are copyright © 1994-2018, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee. Permission is granted in perpetuity, without payment of license fees or royalties, to use, copy, or distribute the LOINC® codes for any commercial or non-commercial purpose, subject to the terms under the license agreement found at https://loinc.org/license/. Additional information regarding LOINC® codes can be found at LOINC.org, including the LOINC Manual, which can be downloaded at LOINC.org/downloads/files/LOINCManual.pdf