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Laboratory Challenges in Clinical Toxicology of Pain Management By Michael (Rusty) Nicar & Marc McCain Clinical Tandem Mass Spectrometry: Cutting Edge Technology for the Clinical Lab Children’s Medical Center October 2010.
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Laboratory Challenges in Clinical Toxicology of Pain Management By Michael (Rusty) Nicar & Marc McCain Clinical Tandem Mass Spectrometry: Cutting Edge Technology for the Clinical Lab Children’s Medical Center October 2010
What is ChronicPain: “a state in which pain persists beyond the natural course of an acute disease or healing of an injury.” Appropriate drug therapy: “recognized by consensus.” “A physician may require laboratory tests for drug levels upon request.” Texas Medical Board Rules 2010
How Many Patients Have Chronic Pain? 1 out of 4 Americans have recurrent pain 1 out of 10 have pain of at least 1 yr duration
CHRONIC OPIOID Rx Hydrocodone is the most prescribed drug in the USA. Others used for pain: morphine, codeine, fentanyl, oxycodone, hydromorphone, oxymorphone, meperidine, methadone. Treatment of Choice for Chronic Pain
Concerns: Drug Diversion (majority of overdose deaths in W. Virginia were due to diversion of opioids, JAMA 2008 300:2613) Taking non-prescribed or illegal drugs Taking more than the prescribed dose Why Do Pain Doctors Drug Test
Estimated Number of Emergency Department Visits in 2006: Opioids – 250,000 Acetaminophen – 50,000 NSAIDS – 35,000 Overdose
CT: Cymbalta, Lyrica, Fentanyl, Hydrocodone GG: Flexeril, Rozerem, Lortab, Allegra, Relafen TK: Duragesic, Percocet, Ambien RT: Lyrica, Norco LV: Zantac, Carisoprodol, Wellbutrin, Topamax, Ambien, Hydrocodone, Celebrex, Flomax, Lexapro, Morphine, Baclofen What Are Patients Taking
RR: Oxycontin, Percocet, Topamax, Metformin, Foltix, Lasix, Singulair, HCTZ, Nifedapine, Diovan, Premarin, Zetia, Omega 3 ML: Sirolimus, Cellcept, Metoprolol, Methadone, Effexor, Synthroid, Norvasc, Lisinopril, Allegra, ASA OP: Skelaxin, Robaxin, Norco, Methadone FH: Fentanyl, Tramadol What Are Patients Taking
State regulatorsrequire physicians to test patients during pain management. Testing improves the Quality of Care. Testing is the Standard Of Care for pain management. Pain Physician 11:S5-S62, 2008. Journal of Pain 10:113-130, 2009. Why Do Pain Doctors Drug Test
“Standard of Practice” for laboratory monitoring of pain patients is urine drug testing. Because it was readily available, rapid, non-invasive, and inexpensive. Not because it is the best scientifically. Laboratory Monitoring
Study from Johns Hopkins in 11,000 chronic pain patients confirmed positives in theiurine specimens (JAT 2008): Amphetamines 2% Barbiturates 3% Benzodiazapines 22% Cannabis 9% Carisoprodol 3% Cocaine 3% Fentanyl 4% Meperidine 1% Methadone 11% Opiates 82% Propoxyphene 4% Urine Drug Positives
At CHOICE Laboratory, I see the following distribution on AU urine drug screens: Negative – 25% Opiate – 50% Opiate + Oxycodone – 16% Drug Screen Results in Dallas
Patients must also be tested for illicit drug use. A study in Kentucky reported the following percentage of pain patients using: Marijuana – 11% (13% of females, 7% of males) Cocaine – 5% Methamphetamine – 2% Pain Physician 9:215-226, 2006 Illicit Drug Use Among Pain Patients
At Choice Labs: Marijuana (THC positives confirmed) – 8% * Cocaine – 2% * Methamphetamine – 1% *no false positives by AU immunoassay screen Illicit Drug Use in Dallas Patients
Crossreactivity of the antibody Can’t identify specific drugs Opiate = morphine + codeine + hydrocodone Cut-offs (Qualitative) Commercial assays come with cut-offs Limitations of Immunoassays
False Positives due to crossreactivity: Cannabinoids – Protonix, Daypro Methadone – diphenhydramine, propoxyphene PCP – meperidine, dextromethorphan Oxycodone - Oxymorphone Limitations of Immunoassays
Immunoassays for single drugs can be quantitative and the Beckman Olympus AU has a semi-quantitative mode for drug classes (ie Opiates, Benzos) – but these assay still use antibodies and have limitations. Confirmation instrument of choice for pain management labs: LC-MS/MS Instrumentation
SPECIMEN PREPARATION: LC-MS/MS requires significantly less specimen prepthan GC/MS GC/MS – treatment and derivatization LC-MS/MS – little or no treatment and no derivatization “Dilute & Shoot” Why LC-MS/MS
SPECIMEN VOLUME: LC-MS/MS requires significantly less specimen than GC/MS GC/MS – 2-5 mLs LC-MS/MS – 0.2-1 mL Why LC-MS/MS
SENSITIVITY LC-MS/MS requires dilution of specimens while GC/MS requires specimen concentration GC/MS Opiate LOD = 100 ng/mL LC-MS/MS Opiate LOD = 25 ng/mL Why LC-MS/MS
Single scan determination of many drugs in minutes. But…..CPT codes are for “assays” and Medicare pays for each assay – not for each drug measured. Why LC-MS/MS
Amphetamine Barbiturates Benzodiazepines Cannabinoids Cocaine MDMA Methadone Opiates PCP PropoxypheneOxycodone TCAs Creatinine Alcohol Cotinine Buprenorphine Adulterants The Pain Drug Screen
Amphetamine, Methamphetamine, MDA, MDMA, MDEA Buprenorphine, Norbuprenorphine 7-aminoclonazepam, Hydroxyalprazolam, Oxazepam, Lorazepam, Nordiazepam, Tamazepam Carisoprodol, Meprobamate Benzoylecgonine Methadone, EDDP Propoxyphene, Norpropoxyphene The Pain Drug Confirmations
Morphine, Codeine, Hydrocodone, Hydromorphone Oxycodone, Oxymorphone, 6-MAM Amitriptyline, Nortriptyline, Imipramine, Desipramine, Doxepin, Desmethyldoxepin, Cyclobenzaprine, Clomipramine, Norclomipramine Fentanyl Tramadol, Meperidine, Normeperidine Amobarbital, Butabarbital, Pentobarbital, Phenobarbital, Butalbital, Secobarbital THC-COOH The Pain Drug Confirmations, cont
Thank You. Children’s Medical Center 2010