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Toxicology

The Toxicology Laboratory serves all 100 counties of the North Carolina Medical Examiner System by providing forensic analytical testing of specimens and evidence from medical examiner cases. The laboratory is responsible for analytical testing, records maintenance and review of analytical testing for more than 8,000 medical examiner cases annually. The staff which consists of toxicologists, chemists, laboratory technicians and administrative technicians performs more than 20,000 analytical tests each year.

Note: Toxicologists at the North Carolina Office of the Chief Medical Examiner (NC-OCME) are limited to interpreting information for our own cases. There are numerous expert consultants who can be contacted for inquiries concerning cases that are not from North Carolina. The Society of Forensic Toxicologists and the American Academy of Forensic Sciences provide links that may help you contact some of these experts. The NC-OCME Toxicology Laboratory has no business affiliation with these consultants and, as such, does not specifically recommend any of them.

Interpretation of Toxicology Results

The following table is provided only as a guide. The data have been compiled from previously published scientific literature and from prior OCME experience; hence these concentrations cannot be regarded as complete for all therapeutic and poisoning situations. When available, references are included for a drug. Also, the appropriate screening assay is designated for each drug. Average concentrations are given in parenthetical from when available. Many of the concentrations listed as toxic are from driving under the influence of drugs (DUID) data and are referenced as such in the comments column. The proper interpretation of postmortem drug concentrations is complex and complicated by many factors including individual variations in response to drugs, tolerance, physical stature, and disease states; the presence of other drugs, and the potential for postmortem changes in blood-drug concentrations. If a toxicological agent is suspected in a case, additional specimens including peripheral blood (PB) and liver (LVR) should be submitted for a more complete investigation.

Last Revision: August 28, 2009

DRUG (Reference) Assay* Therapeutic (mg/L) Toxic(mg/L) Lethal (mg/L) Additional Info.
Acetaminophen (1,2,3,5) N 1-52 30-300 90-320 (170) The toxic effects of acetaminophen are often seen 2-4 days after ingestion and blood levels may not be extremely high at time of death.
Alprazolam (1,2,4,5) E/B 0.005-0.11 0.008-0.64 0.12-2.1 (0.55) The concentrations listed as toxic are from driving under the influence (DUID) cases. Only 30% of those arrested had concentrations greater than 0.10 mg/L.
Amantadine (1,3,5) B 0.1-1.0 1-5 21-48 (33)  
Amitriptyline (1,2,3,5,6) B 0.01-0.25 >0.5 >2 Significant postmortem redistribution can occur with all tricyclics. PB and LVR may be required to resolve difficult cases.
Amoxapine (1,5,6) B 0.01-0.6 0.3-3 0.9-20 (6.9) Significant postmortem redistribution can occur with this drug. PB and LVR may be required to resolve difficult cases.
Amphetamine (1,3,4,5,6) B 0.05-2.0 0.2-3 0.5-41(8.6) Tolerance is important to consider when evaluating the toxicity of this drug.Cardiotoxic with ethanol consumption.
Aripiprazole (1)   0.039 - 0.452 0.063-1.42 unknown  
Arsenic (1,3,6) S 0.002-0.062; 0.27 (herbicide workers) >0.023 >0.6-9.3 (oral); >0.1 (arsine) Detection of chronic arsenic poisoning is complex. Blood specimens alone are insufficient. Tissues and/or hair are usually required.
Benztropine (1,5,6) B 0.005-0.18 >0.05 0.2-1.1 (0.5)  
Bupropion (1,5,7) B 0.05-0.4 0.19-0.22 4-13 (7.3) Postmortem redistribution can occur with this drug. PB and LVR may be required to resolve difficult cases.
Buspirone (1,4,5) B 0.0005-0.003 >0.25 0.44  
Butalbital (1,3,4,5,6) A 1-10 0.1-28 (8.5) 13-30  
Butorphanol (1,3,5,7) S <0.004   0.005  
Caffeine (1,2,3,4,5) B 12-36 50-400 79-344 (183)  
Carbamazepine (1,2,3,5, 7) N 2-12 3-77 35-120  
Carbon Monoxide (1,3,5,6) S <10 % SAT 15-25 % SAT 50 % SAT smokers: 5-6%
Carisoprodol (1,2,3,5,6) N/B 2.6-30 2.6-40 >30 Tolerance is important to consider when evaluating the toxicity of this drug. The concentrations listed as toxic are from driving under the influence (DUID) cases.
Chlordiazepoxide (1,2,3,4,5,6) B 0.4-3.0 1-66 >20  
Chlorpheniramine (1,5) B 0.003-0.02 0.5 >0.5 Significant postmortem redistribution can occur with this drug. PB and LVR may be required to resolve difficult cases.
Chlorpromazine (1,2,3,5) B 0.02-0.30 low dose; 0.75 high dose 0.5-3.0 1-35 (mean= 17) Liver levels can usually differentiate high chronic vs. fatal cases.Significant postmortem redistribution can occur with this drug. PB and LVR may be required to resolve difficult cases.
Citalopram (1,2,5) B <1 1.0-4.0 >3.4 Significant postmortem redistribution can occur with all SSRI's. PB and LVR may be required to resolve difficult cases. The concentrations listed as toxic are from driving under the influence (DUID) cases.
Clomipramine (1,2,3,5) B <0.3 >0.75 >0.54 Significant postmortem redistribution can occur with all tricyclics. PB and LVR may be required to resolve difficult cases.
Clonazepam (1,3,4,5) E 0.01-0.2 >0.1 >0.3-10 (+mtb.) Usually present as mtb. only. The concentrations listed as toxic are from driving under the influence cases.
Clorazepate (1,3,4,5) B 0.12-2.0 (nordiazepam) >5   Prodrug for nordiazepam. No reported OD for this drug taken alone.
Clozapine (1,2,4,5) B 0.06-1.0 0.6-9.5 1.2-13 Significant postmortem redistribution can occur with this drug. PB and LVR may be required to resolve difficult cases.
Cocaine (1,3,4,5) E 0.1-1.0 0.1-5 >0.9 Concentrations listed include the cocaine metabolites benzoylecgonine and ecgonine methyl ester.
Codeine (1,2,3,4,5) E 0.03-0.4 0.2 1-8.8 (2.8)  
Cyanide (1,3,5,6) S <0.06 0.02-5.9 1.1-5.3 (oral); 1-15 (inhalation) Includes both smokers and non-smokers
Cyclizine (1,3,5) B 0.01-0.3 0.75-1 15-80 (oral); 1.5 (IV)  
Cyclobenzaprine (1) B <0.1 0.03-0.35 >0.5 Significant postmortem redistribution can occur with all tricyclics. PB and LVR may be required to resolve difficult cases.
Desipramine (1,2,3,5,6,7) B 0.1-0.8 0.3-2.0 3-16.8 (10.8) Significant postmortem redistribution can occur with all tricyclics. PB and LVR may be required to resolve difficult cases.
Dextromethorphan (1,4,5) B 0.01-0.04 0.1 1.1-18 (3.5) May exhibit PMRD; PB and LVR may be required to resolve difficult cases.
Diazepam (1,2,3,4,5,6,7) B 0.2-1.5 (low dose); 2-4 (high dose) 2-5 >5 Diazepam only deaths are infrequent. Toxic concentrations include DUID.
Diethylpropion (1,3) B <0.2 2 5  
Diflunisal (1) S 40   >260  
Digoxin (1,3,4,5,6,7) S 0.0004-0.003 0.0014-0.007 0.0015-0.03 Blood should be taken from a peripheral source. Vitreous is also acceptable
Diltiazem (1,2,4,5,6) B 0.1-0.4 >0.8 2-33 PMRD may occur, PB and LVR excellent complementary specimens to resolve difficult cases.
Diphenhydramine (1,3,5,6,7) B 0.02-1 .1-10 1.1-31 Lethal concentrations include infant reported deaths. Significant postmortem redistribution can occur. PB and LVR excellent complementary specimens to resolve difficult cases.
Donepezil (1) B 0.02 unknown unknown  
Doxepin (1,3,5,6,7) B <0.25 >0.14 0.7-29 Significant postmortem redistribution can occur with all tricyclics. PB and LVR excellent complementary specimens to resolve difficult cases.
Doxylamine (1,5) B 0.05-0.8 0.2-7.5 0.7-140  
Duloxetine (1) S 0.03   >1  
Ephedrine (1,2,5) B 0.018-0.6   >2.7  
Eszopiclone (1) S < 0.087 unknown unknown  
Ethchlorvynol (1,3,5,6,7) S 0.5-20 18-280 14-400 (115)  
Ethylene glycol (1,3,5,6,7) S na 94-500 >300  
Fenfluramine (1,3,4,5,7) B 0.03-0.3 0.5-2.5 6-16  
Fentanyl (1,4,5,6) E/B 0.001-0.0038 0.003 0.002(IV); >0.007(patch) Tolerance is important to consider when evaluating the toxicity of this drug.
Flunitrazepam (1,5) S 0.005-0.015 .01-.05 0.01-1.6 Toxic concentrations listed are for DUID. Parent drug is rarely detected. Values given are for the 7-amino flunitrazeapm metabolite
Fluoxetine (1,4,5,6,7) B <1.4 (parent + mtb) 0.2-3 (parent + mtb) 2-6 Significant postmortem redistribution can occur with all SSRIs. PB and LVR excellent complementary specimens to resolve difficult cases. The concentrations listed as toxic are from driving under the influence (DUID) cases.
Fluphenazine (1,5, 7) S 0.02 0.05-0.1 0.1  
Fluvoxamine (1,2,5) B <0.9 0.3-0.75 2.8-16 Significant postmortem redistribution can occur with all SSRIs. PB and LVR excellent complementary specimen to resolve difficult cases. The concentration listed as toxic is from a driving under the influence (DUID) case.
Gabapentin (1,5) S <21 45 >250  
Gammahydroxybutyrate (1,5,7) S 20-120 52-551 >400 Lethal levels lower with concomitant use of ethanol.
Guaifenesin (1,5) N 0.3-1.5   14 A lethal conc. of hydrocodone was also detected
Haloperidol (1,3,5,6,7) S <0.1 0.04-0.5 0.2-1  
Heroin (1,3) E 0.1 (morphine in chronic user)   >0.1 (morphine) Tolerance is important to consider when evaluating the toxicity of this drug. Urine or bile are excellent complimetary specimens to use in distinguishing between morphine and heroin use.
Hydrocodone (1,3,4,5,6) E/B <0.1 0.1-0.2 0.1-7 Tolerance is important to consider when evaluating the toxicity of this drug.
Hydromorphone (1,3,4,5,6) E <0.05 0.1 0.07-2.7 Tolerance is important to consider when evaluating the toxicity of this drug.
Hydroxyzine (1,2,3,5,6) B 0.01-1   >1.1  
Ibuprofen (1,3,5,6,7) S <50 100-400 185-680  
Imipramine (1,2,3,5,6,7) B < 0.5 (parent + mtb) 0.5-4.9 1.0-30 Significant postmortem redistribution can occur with all tricyclics. PB and LVR excellent complementary specimen to resolve difficult cases.
Ketamine (1,2,3,5) B <6 7 7-10 Nonmedical IV use can be lethal at conc. as low as 2.0 mg/L
Lamotrigene (1,5,7) A 1-5 (monotherapy) 3-29.1 (combo therapy) 15-30 52  
Levetiracetam (1,5) N <37 400 unknown  
Lidocaine (1,2,5,6,7) B 0.08-6 1.5-19 6-92  
Lithium (1,3,5,6) S <1.3 mEq/L 2.0 mEq/L 2.4-14.0 mEq/L  
Lorazepam (1,5,6,7) S <0.25 0.3-0.6 0.52-2.8 Lower toxic concentrations are found in cases of ingestion of multiple respiratory depressants.
Loxapine (1,3,5,6) B <0.1 0.2-0.72 2-9.5 Significant postmortem redistribution can occur. PB and LVR excellent complementary specimens to resolve difficult cases.
Memantine (1, 10)   0.039-0.082   unknown  
Meperidine (1,4,5,6,7) B 0.06-1.84 >1 8 (oral); 1-8 (IV)  
Meprobamate (1,2,3,4,5,6,7) N <27 10-60 30-240 Tolerance is important to consider when evaluating the toxicity of this drug. DUID cases reported to have meprobamate concentrations of 35-96 mg/L.
Methadone (1,2,3,4,5,6,7) B 0.01-1.06 0.2 0.06-3.1 (0.28) Significant postmortem redistribution can occur. Liver is an excellent complementary specimen to resolve difficult cases. Tolerance is important to consider when evaluating the toxicity of this drug. Toxic concentration listed reflects DUID.
Methamphetamine (1,3,5,6) B 0.01-0.3 0.12-5 0.09-64 DUID cases reported to have methamphetamine concentrations of 0.05-2.6 mg/L.
Methanol (1,3,5,6,7) S   >25 200-900 mg/dL  
Methylenedioxy-methamphetamine (1,5,7) B 0.02-0.35 0.05-1.9 0.6-2.8 (1.8) The concentration listed as toxic is an average value from driving under the influence (DUID) cases.
Metoprolol (1,3,4,5,6) B 0.03-0.5 0.65-18 4.7-142  
Midazolam (1,2,4,5,6) E 0.008-0.6 0.03-1.5 0.07-2.8  
Mirtazapine (1,5) B 0.1-0.3 0.1-2  1-12 The concentration listed as toxic is from a driving under the influence (DUID) case.
Morphine (1,3,4,5,6,7) E 0.01-0.3 0.04-5 0.1-4 Higher doses in caner patients
Naproxen (1,3,4,5) S <120 200-840    
Nefazadone (1,5) B 0.01-2 5 >7  
Nicotine (1,3,5) B 0.005-0.044 0.09-0.4 1.4-63 Lower toxic concentrations are associated with transdermal patch use.
Nifedipine (1,5,6) S <0.1 0.12-0.2 0.15-5.4  
Nortriptyline (1,2,3,5,6,7) B 0.01-0.37 >0.2 1-26 Significant postmortem redistribution can occur with all tricyclics. Liver is excellent complementary specimen to resolve difficult cases.
O-desmethylvenlafaxine (1,5)   0.069-0.3 1-5.1 unknown Significant postmortem redistribution can occur with all tricyclics. Liver is excellent complementary specimen to resolve difficult cases.
Olanzapine (1,5) B 0.02-0.4 0.01-1.0 0.8-4.9 Freeze specimen to prevent analyte degradation:
Oxazepam (1,2,3,4.5,6,7) E 0.1-1.5 0.2-8.0 3-6.1 The concentrations listed as toxic are from driving under the influence (DUID) cases.
Oxcarbazepine (1,5) N 8-12 (mtb) 46 2.5 (parent) 92 (mtb) 10-OH carbazepine metabolite (mtb) accumulates with chronic dosing, whereas, parent analyte does not.
Oxycodone (1,3,4,5,6) B 0.01-0.1 0.01-0.5 (0.24) 0.12-14 Tolerance is important to consider when evaluating the toxicity of this drug. The concentrations listed as toxic are from driving under the influence (DUID) cases.
Oxymorphone (1,11)   0.003-0.005   0.010-0.15 Tolerance is important to consider when evaluating the toxicity of this drug.
Paroxetine (1,2,5) B 0.1-0.6 0.35-0.4  0.7-4.6 Significant postmortem redistribution can occur with all SSRIs. Liver is excellent complementary specimen to resolve difficult cases.
Pentobarbital (1,2,3,4,5,6,7) A 1-10 >10 5-169  
Phencyclidine (1,3,5,6) S na .007-0.8 0.3-25  
Phenobarbital (1,2,4,5,6) A 6-48 30 >50  
Phentermine (1,3,4,5) B 0.03-0.51 0.2 1-7.6  
Phenylpropanolamine (1,2,3,5) B 0.1-0.5 0.3-2 >2  
Phenytoin (1,2,3,5) A 5-20 20-50 >43  
Pregabalin (1) S 1.3-4.9 unknown unknown  
Primidone (1,3,5,6,7) A 4-20 >9 65  
Procainamide (1,3,5,6,7) S 4-10 10-16 17-260 (100)  
Promethazine (1,2,4,5,6) B <0.5 0.17-1 0.16-12  
Propoxyphene (1,2,6,7) B 0.13-1.0 >0.5 >2 (parent only)  
Propanolol (1,2,4,5,6,7) B <0.34 1-4.5 2-29  
Pseudoephedrine (1,3,5) B <1 unknown 10-66  
Quetiapine (1) B <1 1.1-8.8 5-49 PMRD may occur, PB and LVR excellent complementary specimens to resolve difficult cases.
Quinidine (1,3,4,5,6, 7) B <6 6-10 10-45  
Quinine (1,3,5,7) B 0.22-15 >10 6-24 (13)  
Risperidone (1,5) S 0.006-0.11 1.1 1.8  
Salicylate (1,2,3,5,6,7) S 10-300 >200 400-7300 (600) Higher conc. are with arthritic patients that have been titrated to this level (44-330).
Sertraline (1,5) B <0.5 >0.2 >1.5 (parent only) PMRD may occur, PB and LVR excellent complementary specimens to resolve difficult cases.
Temazepam (1,3,4,5,7) E 0.2-1.1 1 3-14  
Theophylline (1,2,3,5,6,7) N 4.0-20 >20 25-250  
Thioridazine (1,2,5,6,7) B 0.14-2.6 1.1-14 1-18 (5.4) PMRD may occur, PB and LVR excellent complementary specimen to resolve difficult cases.
Topiramate A 2.4-8.0 5.9 >49 The concentration listed as toxic are from driving under the influence (DUID) cases.
Tramadol (1,5,7) B 0.1-1 0.01-5.3 1.1-23 The concentrations listed as toxic are from driving under the influence (DUID) cases.
Trazodone (1,3,5,6,7) B <2.5 4-26 9.4-34 PMRD may occur, PB and LVR excellent complementary specimens to resolve difficult case. The concentrations listed as toxic are from overdose cases in which the patient survived with supportive therapy.
Triazolam (1,3,5,6) E <0.004 0.004-0.04 0.01-0.22 The concentrations listed as toxic are from driving under the influence (DUID) cases.
Trichlorethanol (1,2,5) S 2-27 40-330 20-640 (250) Mtb. of chloral hydrate. Significant postmortem redistribution can occur. PB and LVR may be required to resolve difficult cases.
Trimipramine (1,2,3,5) B 0.011-0.241 0.5-1.0 0.4-12 PMRD may occur, PB and LVR excellent complementary specimens to resolve difficult cases.
Valproic acid (1,3,5,6,7) S 40-125 (plasma); 27-50 (whole blood) 52-148 (hepatotoxic); 482-2120 (coma) 269-2204  
Venlafaxine (1,5) B <1 6-24 6.6-89 (56) PMRD may occur, PB and LVR excellent complementary specimens to resolve difficult cases.
Verapamil (1,2,4,5,6,7) B 0.03-1 1-4 0.9-85 (11)  
Zaleplon (7) S 0.015-0.3 0.037-0.1 >2.2  
Ziprasidone (1) S 0.045-0.14 unknown unknown  
Zonisamide (1,5,8,9) N 10.0 - 30 > 30 44  
Zolpidem (1,2,4,5,7) B <0.3 0.07-0.7 >1 The concentrations listed as toxic are from driving under the influence (DUID) cases. Tolerance should be considered when evaluating the toxicity of this drug.

*Assay Interpretation

A=Acids
B=Bases
N=Neutrals
E=Immunoassay
S=Special

References:

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  1. A. Periclou, D. Ventura, N. Rao, and W. Abramowitz. Pharmacokinetic study of Memantine in healthy and Renally Impaired Subjects. Clin. Pharmacol. Ther. 2006; 79 (1): 134-143

  2. D Garside, RL Hargrove, RE Winecker. Concentration of Oxymorphone in Postmortem Fluids and Tissue. J Anal. Toxicol. April, 33:121-128 (2009).


 

 

 

Last Modified: November 22, 2013