IRB-HSR# 14145 R,S Methadone: Analgesia and Pharmacokinetics in Adolescents Undergoing Scoliosis Correction

Study Overview
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Brief Summary
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This is a pilot study to determine the pharmacokinetics of (R,S) methadone in adolescents. A total of approximately 15 patients will be required. The purpose is to determine the levels of R, S methadone at various time intervals after drug administration. Patients will receive methadone 0.25 mg/kg IV at induction and a standardized anesthetic of remifentanil and propofol. At the conclusion of surgery (45 minutes prior to the completion), the patients will receive a loading dose of morphine based on respiratory rate. A morphine PCA will be utilized for postoperative analgesia. Pharmacokinetic data will be collected in addition to VAS scores, patient and parental satisfaction with analgesia, and a functional pain assessment.

Detailed Description
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Study Procedures Following Surgery: VAS scores will be recorded at intervals of 1,2,3,4,5,6,8,12,16,20,24, 36, 48 , 72 hrs (after extubation). Blood samples for PK will require 5ml per sample and may be obtained from an existing IV or direct phlebotomy and will be obtained at 0min, 5min, 10 min, 15min, 20 min, 40 min, 1hr, 2hrs, 3hrs, 4hrs, 5hrs, 6hrs, 8hrs, 10 hrs, 12hrs, 24hrs, 48 hrs, 72hrs, and 96hrs after study drug administration.

Official Title
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IRB-HSR# 14145 R,S Methadone: Analgesia and Pharmacokinetics in Adolescents Undergoing Scoliosis Correction

Conditions
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Scoliosis

Intervention / Treatment
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* Drug: methadone


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Pediatric scoliosis surgery secondary idiopathic scoliosis, congenital scoliosis, Age 12 - 19 inclusive ASA class I-II. Exclusion Criteria: Preoperative opioid therapy in previous 2 weeks Known hepatic or renal impairment Inability to assess pain score due to neurological impairment, hearing impairment Allergy to methadone, morphine, fentanyl, propofol or remifentanil Pregnant or nursing Taking SSRI's, MAOI,anticonvulsants, gabapentin or lyrica ASA III or greater patients are excluded pre-existing chronic pain

Ages Eligible for Study
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Minimum Age: 12 Years
Maximum Age: 19 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Health Services Research
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Methadone<br>0.25mg/kg IV of racemic methadone at the induction of anesthesia. | Drug: methadone<br>* 0.25mg/kg IV of racemic methadone at the induction of anesthesia.<br>* Other names: 0.25mg/kg IV of racemic methadone;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| methadone levels | Tmax (time to maximum methadone concentration) Cmax (maximum concentration) T1/2 (half-life) AUC last (area under the curve from time 0 to last sample point) AUC inf (area under the curve from time 0 to infinity) VZ (Volume of distribution in the terminal phase) CL (clearance) | 0min, 5min, 10 min, 15min, 20 min, 40 min, 1, 2hrs, 3hrs, 4hrs, 5hrs, 6hrs, 8hrs, 10 hrs, 12hrs, 24hrs, 48 hrs, 72hrs, and 96hrs. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Methadone pharmacokinetics in adolescents