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Plasma Concentration of Ketamine and Norketamine .

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ClinicalTrials.gov Identifier: NCT02016664
Recruitment Status : Completed
First Posted : December 20, 2013
Last Update Posted : March 1, 2016
Sponsor:
Information provided by (Responsible Party):
Qutaiba Tawfic, Lawson Health Research Institute

Brief Summary:
Oral ketamine is increasingly used by doctors to both reduce the amount of narcotic pain medication consumed and to improve chronic pain management in difficult cases. How much is absorbed when taken orally, as opposed to intravenously ,is unknown. Ketamine may cause sedation, and occasionally cognitive impairment. Therefore, there are safety concerns associated with its usage as an out-patient may engage in activities where cognitive impairment is dangerous,such as driving. This study is designed to measure the plasma concentrations of ketamine and its active metabolite, norketamine, in people taking low dose oral ketamine for chronic pain. The goal of the study is to verify that low dose oral ketamine produces plasma concentrations below the level associated with toxic symptoms,and thus can be safely used long-term for the treatment of chronic pain .

Condition or disease Intervention/treatment Phase
Chronic Pain Drug: Ketamine Not Applicable

Detailed Description:

This is a non-randomized, cohort study to measure the serum uptake of low dose oral ketamine in chronic pain patients. The SJHC pharmacy has a list of patients to whom they dispense oral ketamine. We plan to recruit fifteen patients from this patient group.

This is a pilot study and very little information is available to help with sample size calculations. We also plan to measure change in mean pain score from Day to Day 14 using the Brief Pain Inventory (BPI) This data will aid the design and calculation of sample size in future studies. Study Design: Days 1-7: Following informed consent, the patient's demographic information and initial assessment will be completed on Day 1 at the first visit. They will be allowed to continue all usual systemic analgesic medications. They will be given instructions on how to take the study medication and will be given a list of foods that could possibly induce or inhibit the enzyme, Cyp3A4 or Cyp2B6 (i.e. grapefruit or grapefruit juice). Subjects will be given a 7 day supply of 10 mg ketamine tablets. The patients will be instructed to take one ketamine tablet three times per day at specified times for seven days and to return to clinic on Day 7. They will be instructed not to take their morning dose of ketamine and to eat a light breakfast on Day 7. Upon arrival, the patients will complete the Brief Pain Inventory and side effects questionnaire. The patient will have a 20 gauge (saline locked) IV started in the antecubital fossa to allow for five blood samples: Time Zero, 30, 60, 90 and 120 minutes. The first blood sample at Time 0 will be obtained just before the patient takes his/her oral dose of ketamine (trough concentration). The four remaining samples will be taken after the patient ingests his/her 10 mg ketamine dose. Time Activity Arrival Complete BPI, side effect questionnaire Time Zero Blood draw, then take 10mg oral ketamine dose 30 minutes post ingestion Blood draw 60 minutes post ingestion Blood draw 90 minutes post ingestion Blood draw 120 minutes post-ingestion Blood Draw Days 8-14: The subjects will be given a supply of 20 mg ketamine capsules and instructed to take them three times per day, at specified times, and to return to clinic on Day 14. The instructions and procedures at the second clinic visit will be the same as on Day 7.


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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 12 participants
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Official Title: Plasma Concentration of Ketamine and Norketamine in Patients on Oral Ketamine for Chronic Neuropathic Pain : A Pilot Study.
Study Start Date : April 2014
Actual Primary Completion Date : December 2015
Actual Study Completion Date : December 2015

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Chronic Pain
Drug Information available for: Ketamine

Arm Intervention/treatment
Experimental: Chronic pain patients on oral ketamine

Days 1-7:

Subjects will be given a 7 day supply of 10 mg ketamine tablets three times per day for seven days and to return to clinic on Day 7. They will be instructed not to take their morning dose of ketamine and to eat a light breakfast on Day 7. Upon arrival, the patient will have a 20 gauge (saline locked) IV started in the antecubital fossa to allow for five blood samples: Time Zero,30, 60,90 and 120 minutes. The first blood sample at Time 0 will be obtained just before the patient takes his/her oral dose of ketamine.

Days 8-14:

The subjects will be given a supply of 20 mg ketamine capsules and instructed to take them three times per day, at specified times, and to return to clinic on Day 14. The instructions and procedures at the second clinic visit will be the same as on Day 7.

Drug: Ketamine
The St.Joseph's Heath Care Pharmacy will supply the compounded oral ketamine capsules. Patients who are going to participate in this study are already taking this oral ketamine as a part of their chronic pain medications. No new patient will start oral ketamine for the sake of this study. Two doses of oral ketamine will be used for the same patient, 10 mg and 20 mg every 8 hours. These doses are the standard doses in our clinic. Other clinics using much higher doses.




Primary Outcome Measures :
  1. Plasma level of oral ketamine and norketamine at two different doses. [ Time Frame: 0,30,60,90 and 120 min after ingestion. ]
    Plasma level of ketamine and norketamine will be tested just before ingestion of oral ketamine (trough level) and then after at 30,60,90 and 120min. Patients will be already using oral ketamine therapy for 7 days before the test. This test will be repeated twice on 2 different doses (10 and 2o mg q 8 hr).


Secondary Outcome Measures :
  1. Mean Pain Score [ Time Frame: week 1 and week 2 ]
    Mean pain score will be recorded at the end of one week of ingestion for each dose.



Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 75 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  • Patient currently takes oral ketamine for the treatment of chronic neuropathic pain.
  • Age >18 and < 75 years
  • Both males and females 4.Ability to speak English adequately to understand the consent and participate in the study
  • No other route of ketamine within past 7 days (Topical/IV)

Exclusion Criteria:

  • Patient receiving liver enzyme inducers or inhibitors of Cytochrome CYP3A4, or CYP2B6 like clarithromycin, rifampin, and recent ingestion of grapefruit juice.
  • Patients who have had gastric bypass surgery
  • Patients who did not follow the prescribed protocol
  • Renal Failure defined as Creatinine Clearance <50 mL/min
  • Hepatic insufficiency by history

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02016664


Locations
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Canada, Ontario
St.Joseph's Health Care, Western University
London, Ontario, Canada, N6A4V2
Sponsors and Collaborators
Lawson Health Research Institute
Investigators
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Principal Investigator: Patricia Morley-Foster, MD, FRCPC Department of Anesthesia and Perioperative Medicine, Western University, Canada.

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Responsible Party: Qutaiba Tawfic, Clinical Fellow, Lawson Health Research Institute
ClinicalTrials.gov Identifier: NCT02016664     History of Changes
Other Study ID Numbers: OKPCS
First Posted: December 20, 2013    Key Record Dates
Last Update Posted: March 1, 2016
Last Verified: February 2016

Keywords provided by Qutaiba Tawfic, Lawson Health Research Institute:
Chronic Pain, Ketamine, Safety

Additional relevant MeSH terms:
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Ketamine
Chronic Pain
Pain
Neurologic Manifestations
Signs and Symptoms
Analgesics
Sensory System Agents
Peripheral Nervous System Agents
Physiological Effects of Drugs
Anesthetics, Dissociative
Anesthetics, Intravenous
Anesthetics, General
Anesthetics
Central Nervous System Depressants
Excitatory Amino Acid Antagonists
Excitatory Amino Acid Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action