Testing human hair for carbamazepine in epileptic patients: is hair investigation suitable for drug monitoring?

Current Principles in the Management of Drug-Resistant Epilepsy

Drug-resistant epilepsy is associated with poor health outcomes and increased economic burden. In the last three decades, various new antiseizure medications have been developed, but the proportion of people with drug-resistant epilepsy remains relatively unchanged. Developing strategies to address drug-resistant epilepsy is essential. Here, we define drug-resistant epilepsy and emphasize its relationship to the conceptualization of epilepsy as a symptom complex, delineate clinical risk factors, and characterize mechanisms based on current knowledge. We address the importance of ruling out pseudoresistance and consider the impact of nonadherence on determining whether an individual has drug-resistant epilepsy. We then review the principles of epilepsy drug therapy and briefly touch upon newly approved and experimental antiseizure medications.

Hair as a matrix in monitoring drug epilepsy therapy

Hair is considered an efficient tool to investigate drug-related histories; thus, the selection of the method of sample preparation is important to obtain a reliable result. The aim of this study was to compare two methods of hair preparation (cutting and pulverizing) to analyse levetiracetam concentration in hair. An additional aim was to evaluate the potential usefulness of the levetiracetam concentration measured as an index of a dosing schedule. Four groups of 12 rats were included in the experiment. Depending on the group, the rats received 10 mg/kg of levetiracetam intraperitoneally every 24, 48 and 72 hours for 30 days. The control group was not treated. At the end of the drug administration, the rats' hair was shaved, cut or pulverized and analysed by the LC/MS-MS method to determine the concentration of levetiracetam. A stronger correlation between the mean hair levetiracetam concentration in hair and the number of drug doses was found in pulverized hair than in cut hair. A smaller standard deviation between the results was obtained in the case of pulverized hair. The results indicate that pulverization gives a more reliable result of drug concentration in hair than cutting and that drug concentration in hair can reflect the scheme of levetiracetam administration.

Levetiracetam concentration in hair is associated with the time schedule of administration: Study on rats

Measurement of hair drug content may be a reliable biomarker of the history of drug exposure, allowing to assess patient long-term compliance. Studies on correlations between antiepileptic drugs intake and their hair contents are limited. The aim of the study was to determine the association between the history of levetiracetam administration and its content in rat hair in controlled laboratory conditions. Additionally, the effects of levetiracetam on hair growth rate and body-weights were examined. Three groups of 12 rats each were exposed to different schedules of levetiracetam administration (10 mg/kg i.p.: every 24, 48 and 72 hours) for 30 days. The control group received daily saline injection. Levetiracetam concentrations in hair were assessed by validated LC-MS/MS method. The mean hair concentrations were as follows: 300 (±100), 170 (±60) and 130 (±80) ng/mg for rats receiving levetiracetam every 24, 48 and 72 hours, respectively. The levetiracetam accumulation in the hair was correlated with the total number of doses received (r = .699, P < .001). Levetiracetam did not affect the hair growth rate and rat body-weight. The concentration of levetiracetam measured in rat hair represents a reliable marker. It may reflect the adherence to levetiracetam treatment; however, further studies on human beings are needed.

Comparison of plasma, saliva, and hair lamotrigine concentrations

BACKGROUND

In some clinical situations (pregnancy, aging, drug resistance, toxicity), measurements of lamotrigine plasma levels may be reliable. Limited studies indicate that saliva and hair could be alternative sources for monitoring lamotrigine therapy. The drug content in hair can also be used to assess the history of drug therapy and to ascertain long-term patient compliance. The aims of this study were to 1) determine the correlations among plasma, saliva, and hair lamotrigine concentrations, 2) evaluate saliva as an alternative matrix for monitoring drug levels and 3) evaluate hair as a source of information on adherence to antiepileptic treatment and on the correlation of hair concentrations with clinical outcomes in patients with epilepsy.

METHODS

Plasma, saliva, and hair lamotrigine concentrations were measured by liquid chromatography-tandem mass spectrometry in positive ionization mode. The study group (n = 85) was recruited among the epileptic patients at the Institute of Psychiatry and Neurology, Warsaw, Poland.

RESULTS

Plasma concentrations were not influenced by sex, age, or the concomitant use of other antiepileptic drugs. Lamotrigine saliva and plasma concentrations were strongly correlated (r = 0.82, p < 0.001). Lamotrigine hair concentrations were correlated with the plasma concentrations (r = 0.53, p < 0.001) and daily dose in mg/kg (r = 0.23, p = 0.024). The analysis revealed no significant correlation between lamotrigine hair levels and the number of seizures in the previous 3 months (r = -0.1, p > 0.05).

CONCLUSIONS

The lamotrigine saliva concentration is strongly correlated with its plasma level, and saliva can be used as an alternative matrix to plasma for monitoring. Lamotrigine can also be successfully measured in hair, and the drug levels in hair tend to be correlated with the levels in plasma. However, lamotrigine levels in hair may not correspond to clinical outcomes (i.e., seizure episodes).

Earwax as an alternative specimen for forensic analysis

In this work, we presented, for the first time, earwax as an alternative forensic specimen for detecting 12 neuropsychotic drugs employing liquid chromatography-tandem mass spectrometry in positive and negative ion modes after straightforward extraction with methanol. The method was validated and standard curves were established by external calibration with correlation coefficients >0.99. All precision, accuracy, matrix effects, extraction recoveries, and carryover were within acceptable limits; limits of quantification were sufficiently low to quantify almost all the samples tested. To confirm the feasibility of the study, earwax specimens were collected from actual patients treated with different combinations of the 12 drugs and analyzed by our method; the 12 drugs could be quantified from the earwax specimens of the users successfully, showing usefulness of earwax specimens, because of its noninvasive sampling and the storage of drug(s) for relatively long time together with its being relatively less contaminated by environmental impurities. This study is pioneering; many detailed studies on earwax as an alternative specimen remain to be explored.

Determination of Opioid Analgesics in Hair Samples Using Liquid Chromatography/Tandem Mass Spectrometry and Application to Patients Under Palliative Care

Hair testing procedures allow a cumulative reflection of long-term drug abuse and are useful as a test for compliance in clinical toxicology. In the present study, liquid chromatography coupled with tandem mass spectrometry was used to determine analgesic opioid drugs in hair samples. The procedure used a simple methanolic extraction, and the evaporated extract was analyzed directly. A selective and sensitive procedure for the simultaneous determination of bisnortilidine, nortilidine, tilidine, buprenorphine, codeine, oxycodone, fentanyl, norfentanyl, hydromorphone, morphine, normorphine, oxymorphone, methadone, piritramide, and tramadol was developed and fully validated. The method fulfilled validation criteria and was shown to be sensitive, with limits of detection ranging from 0.008 to 0.017 ng/mg hair matrix, and precision ranging between 3.1% and 14.9 %. The applicability of the method was shown by analysis of authentic hair samples from patients receiving opioids for the treatment of cancer pain (eg, fentanyl was detected in concentrations up to 0.292 ng/mg, tramadol in concentrations up to 0.612 ng/mg of hair of 1 patient). Hair analysis was shown to be a complementary and useful tool in monitoring the drug-taking behavior of patients consuming opioid analgesics for the treatment of pain. In self-reports and medical records especially, the ingestion of tramadol and methadone was found to be dramatically underreported. In summary, hair analyses gave important additional information for the medical treatment of patients, the results often coming as a surprise to even the attending physicians.

Deposition of cannabinoids in hair after long-term use of cannabis

Hair analysis has shown great potential in the detection and control of drug use. Whether an assay is of quantitative value roughly corresponding to the amount of drug consumed, is still a matter of debate. The present investigation was aimed at a possible relationship between the cannabinoid concentration in hair and the cumulative dose in regular users of cannabis. Hair samples from the vertex region of the scalp were obtained from 12 male regular users of cannabis, and 10 male subjects with no experience of cannabis served as controls. None of the subjects had his hair permed, bleached or colored. Cannabis users provided information on drug use such as the current cannabis dose per day, the cumulative cannabis dose of the last 3 months, as well as the frequency of cannabis use during the last year. The concentration of delta-9-tetrahydrocannabinol (THC), cannabinol (CBN) and cannabidiol (CBD) in hair was determined using gas chromatography-mass spectrometry. Cannabinoids were present in any hair sample of cannabis users, but were not detectable in control specimens. An increase in the amount of cannabinoids in hair with increasing dose was evident. The concentration of major cannabinoids (sum of THC, CBD and CBN) was significantly correlated to either the reported cumulative cannabis dose during the last 3 months or to the cannabis use during the last 3 months estimated from the daily dose and the frequency per year (r=0.68 or 0.71, p=0.023 or 0.014). A significant relationship between THC and the amount of cannabis used could not be established. As a conclusion, the sum of major cannabinoids in hair of regular users may provide a better measure of drug use than THC.

Analytical pitfalls in hair testing

This review focuses on possible pitfalls in hair testing procedures. Knowledge of such pitfalls is useful when developing and validating methods, since it can be used to avoid wrong results as well as wrong interpretations of correct results. In recent years, remarkable advances in sensitive and specific analytical techniques have enabled the analysis of drugs in alternative biological specimens such as hair. Modern analytical procedures for the determination of drugs in hair specimens - mainly by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) - are reviewed and critically discussed. Many tables containing information related to this topic are provided.

New trends in hair analysis and scientific demands on validation and technical notes

This review focuses on basic aspects of method development and validation of hair testing procedures. Quality assurance is a major issue in drug testing in hair resulting in new recommendations, validation procedures and inter-laboratory comparisons. Furthermore recent trends in research concerning hair analysis are discussed, namely mechanisms of drug incorporation and retention, novel analytical procedures (especially ones using liquid chromatography-mass spectrometry (LC-MS) and alternative sample preparation techniques like solid-phase microextraction (SPME)), the determination of THC-COOH in hair samples, hair testing in drug-facilitated crimes, enantioselective hair testing procedures and the importance of hair analysis in clinical trials. Hair testing in analytical toxicology is still an area in need of further research.

State of the art in hair analysis for detection of drug and alcohol abuse

Hair differs from other materials used for toxicological analysis because of its unique ability to serve as a long-term storage of foreign substances with respect to the temporal appearance in blood. Over the last 20 years, hair testing has gained increasing attention and recognition for the retrospective investigation of chronic drug abuse as well as intentional or unintentional poisoning. In this paper, we review the physiological basics of hair growth, mechanisms of substance incorporation, analytical methods, result interpretation and practical applications of hair analysis for drugs and other organic substances. Improved chromatographic-mass spectrometric techniques with increased selectivity and sensitivity and new methods of sample preparation have improved detection limits from the ng/mg range to below pg/mg. These technical advances have substantially enhanced the ability to detect numerous drugs and other poisons in hair. For example, it was possible to detect previous administration of a single very low dose in drug-facilitated crimes. In addition to its potential application in large scale workplace drug testing and driving ability examination, hair analysis is also used for detection of gestational drug exposure, cases of criminal liability of drug addicts, diagnosis of chronic intoxication and in postmortem toxicology. Hair has only limited relevance in therapy compliance control. Fatty acid ethyl esters and ethyl glucuronide in hair have proven to be suitable markers for alcohol abuse. Hair analysis for drugs is, however, not a simple routine procedure and needs substantial guidelines throughout the testing process, i.e., from sample collection to results interpretation.

Determination of antiepileptic drugs in biological material

Current analytical methodologies applied to the determination of antiepileptic drugs in biological material are reviewed. The role of chromatographic techniques is emphasized. Special attention is focused on new chemical entities as well as current trends such as high-speed liquid chromatographic techniques, hyphenated techniques and electrochromatography techniques. A review with 542 references.

The concentration of three anti-seizure medications in hair: the effects of hair color, controlling for dose and age

BACKGROUND

This paper assess the relationship between the quantity of three anti-seizure medications in hair and the color of the analyzed hair, while controlling for the effects of dose, dose duration, and patient age for 140 clinical patients undergoing anti-seizure therapy. Three drugs are assessed: carbamazepine (40 patients), valproic acid (40 patients), and phenytoin (60 patients). The relationship between hair assay results, hair color, dose, dose duration, and age is modeled using an analysis of covariance. The covariance model posits the hair assay results as the dependent variable, the hair color as the qualitative categorical independent variable, and dose, dose duration, and age as covariates. The null hypothesis assessed is that there is a no relationship between hair color and the quantity of analyte determined by hair assay such that darker colored hair will demonstrate higher concentrations of analyte than lighter colored hair.

RESULTS

The analysis reveals that there is a significant relationship between dose and concentration for all hair color categories independent of the other covariates or the categorical independent variable.

CONCLUSION

There does not appear to be any relationship between carbamazepine concentration and hair color. There is a weak relationship between hair color and valproic acid concentration, which the data suggest may be mediated by age. There is a significant, moderate relationship between phenytoin concentration and hair color such that darker colored hair has greater concentration values than lighter colored hair.

Relation between dosage of carbamazepine and concentration in hair and plasma samples from a compliant inpatient epileptic population

Compliance is a problem in all areas of therapeutic medicine. Methods for its assessment are classified as either indirect or direct. Indirect assessment is based on criteria such as pill counts, questionnaires, and self-reporting; direct methods involve the analytic measurement of the drugs in biologic fluids such as plasma or urine. Drugs taken either therapeutically or recreationally become incorporated into hair. This prospective study investigated the relation between the daily intake of the antiepileptic drug carbamazepine and both its trough plasma and hair concentrations in a highly supervised inpatient population of patients with epilepsy during a period of 6 months. Results showed that although there was a significant variation between patients resulting from the substantial range in the daily intake of carbamazepine (800-2400 mg/day), the intrapatient variation in both trough plasma and hair concentrations during the 6-month period were not significantly different. The mean intrapatient percentage coefficient of variation in total plasma and hair concentrations of carbamazepine was 11.5 +/- 4.7 and 15.0 +/- 5.2, respectively, both of which were independent of the daily dosage. This relatively small intrapatient variation in hair concentration over time and its close relation to the plasma concentration suggests that hair analysis may be a complementary and useful technique in monitoring drug-taking behavior.

Phenytoin concentration in head hair sections: a method to evaluate the history of drug use

Phenytoin (PHT) levels were determined in sections of head hair taken from 60 patients (34 males and 26 females), aged 5 to 69 years, who were regularly receiving the drug. The hair sectional analysis included dissolution, liquid phase extraction procedures, and immunoassay (Abbott TDx) or high-pressure liquid chromatography (HPLC) analytical techniques. The values of PHT levels in the hair from the first section (close to the hair root) to the fifth section for female patients were 18.0, 15.2, 13.1, 11.6, and 10.7 microg/g, respectively, according to HPLC measurements. There were no significantly different results obtained using the immunoassay technique, according to which the mean values of PHT in the hair sections were 17.9, 15.2, 13.1, 11.9, and 10.9 microg/g, respectively, from the first to the fifth sections. The corresponding mean values for male patients by HPLC and immunoassay techniques, respectively, were 17.9, 15.0, 12.5, 12.1, and 12.3 microg/g and 17.8, 14.9, 12.2, 11.9, and 121 microg/g. Generally, a reduction of drug concentrations in hair from the first to the subsequent segments was observed. The hair PHT concentrations were found to be dependent on the dosage (by fluorescence polarization immunoassay: r = 0.987, p < or = 0.02; by HPLC: r = 0.988, p < or = 0.02). Mean dose and assay outcome values by hair color and correlation between hair PHT mean values, daily mean doses of the drug, and patients' age are presented. The differences among doses according to hair color were significant. PHT hair profiles from female and male patients compared with the mean +/- SD concentrations of the hair sections are discussed. The data indicate the possible use of hair section testing as a marker of the dosage history and the compliance of patients receiving long-term treatment with PHT.

Use of headspace solid-phase microextraction (HS-SPME) in hair analysis for organic compounds

Headspace solid phase microextraction (HS-SPME) has advantages of high purity of the extract, avoidance of organic solvents and simple technical manipulation and can be used in combination with gas chromatography-mass spectrometry (GC-MS) in the hair analysis of a number of drugs. HS-SPME coupled with the hydrolysis of the hair matrix by 4% sodium hydroxide in the presence of excess sodium sulphate and of a suitable internal standard proved to be a convenient one-step method for the measurement of many lipophilic basic drugs such as nicotine, amphetamine derivatives, local anaesthetics, phencyclidine, ketamine, methadone, diphenhydramine, tramadol, tricyclic antidepressants and phenothiazines. Detection limits were between 0.05 and 1.0 ng/mg. From spiked 10-mg hair samples absolute recoveries between 0.04 and 5.7% were found. These recoveries decreased considerably if larger sample amounts were used, perhaps due to increased drug solubility in the aqueous phase or to elevated viscosity in the presence of dissolved hair proteins. Because of the phenolic hydroxyl group a change of pH after alkaline hair digestion (by adding excess orthophosphoric acid) was necessary for the detection of delta 9-tetrahydrocannabinol (delta 9-THC), cannabinol (CBN) and cannabidiol (CBD) by HS-SPME. Nevertheless, the detection limits were such that only CBN could be detected in hair of a consumer. Clomethiazole, a compound hydrolysed in alkali, was measured by HS-SPME after extraction with aqueous buffer. The detection limit was 0.5 ng/mg. Cocaine could not be detected by HS-SPME. The application of HS-SPME to hair samples from several forensic and clinical cases is described.

Testing hair for pharmaceuticals

More than hundred pharmaceuticals, drugs of abuse or doping agents have been reported to be detectable in human hair. This article reviews the analysis of 90 drugs and drug metabolites by chromatographic procedures, including the pretreatment steps, the extraction methods, the reported limits of detection and the measured concentrations in real human hair samples. Some progress is observed in the detection of low dose drugs, like fentanyl or flunitrazepam. The general tendency in the last years, to highly sophisticated techniques (GC-MS-NCI, HPLC-MS, GC-MS-MS) illustrates well this constant fight for sensitivity. Some new findings, based on the recent experience of the authors, are also added.

Hair analysis as a potential index of therapeutic compliance in the treatment of epilepsy

Twenty-three patients resident at the Chalfont Centre for Epilepsy, who have been prescribed carbamazepine either as monotherapy or in combination with other antiepileptic drugs have been monitored for a period of 6 months. Monthly hair samples along with concomitant plasma samples have been collected over this period and the 1 cm from scalp hair sections and the plasma concentrations of carbamazepine measured. The relationship between dose, hair and plasma concentrations have been assessed as well as the monthly variability in the concentration of carbamazepine in both matrices.

Hair opiates during pain treatment

Opiates are commonly used for pain treatment, especially for sharp pain like carcinoma pain. Two opiates are generally prescribed in our hospital: morphine and codeine in association with paracetamol. Most of the patients were given oral forms. Incorporation of morphine and codeine in hair of these patients was studied. Opiates testing in hair is performed by gas chromatography-mass spectrometry (GC-MS), using acid hydrolysis in presence of deuterated standards, a three-step liquid extraction and derivatization with BSTFA + TMCS. Results of codeine and morphine content in hair during pain treatment showed no correlation group between dose and concentration of the drug in hair. However, codeine values in hair during pain treatment compared to codeine in the hair of codeine abusers was significantly different (P < 0.0001).

Detection of benzodiazepines and other psychotropic drugs in human hair by GC/MS

For the detection of psychotropic drugs in human hair we collected hair obtained from 21 corpses that died from an overdose of legal or illicit drugs. These persons were known to have taken psychotropic drugs prior to their death as determined by post-mortem toxicological analysis in blood. After washing, cutting hair into segments of 3 cm, pulverization, enzymatic hydrolysis with beta-glucuronidase/arylsulfatase and solid phase extraction, drugs were identified by GC/MS. For quantification of flunitrazepam we used its metabolite amino-flunitrazepam; for oxazepam and lorazepam we used the hydrolysed forms of the corresponding drugs. In the hair of 21 subjects tested we found in 20 cases nordazepam, in 15 cases diazepam, in 15 cases oxazepam and in eight cases flunitrazepam with maximal concentrations of 1.8, 2.2, 3.4 and 9.5 ng/mg hair respectively. In addition to these compounds, in subject 11 to 21 we also analyzed for and detected amitriptyline (seven positive), carbamazepine (eight positive), lormetazepam (three positive) and lorazepam (one positive) and found maximal concentrations of 106.0, 13.5, 29.0 and 4.9 ng/mg hair respectively. The comparison of hair analysis versus post-mortem blood and tissues analysis of all the drugs studied shows that in 40 cases, where a positive result was found in blood, the corresponding drug could also be detected in hair in 37 cases. Our results show that hair testing is complementary to classical post-mortem analysis in forensic toxicology.

[A new tool for biological study: hair analysis. Value in medical practice]

Testing hair has been used since two hundred years for arsenic determination. Fifteen years ago, Baumgartner published the first report on the detection of morphine in the hair of heroin abusers by radio-immuno-assay. Today the development of new methods like gas chromatography/mass spectrometry has permitted numerous applications based on the analysis of organic substances trapped in hair. Personal observations and a review of the literature are presented in this paper to document the following clinical applications: hair as a screening procedure of psychiatric patients; hair and epileptic management; hair as a tool for monitoring neuroleptics; hair as evidence of gestational drug exposure; hair nicotine as a marker of passive exposure to tobacco; detection and clinical survey of heroin addict; evaluation of pharmaceutical exposure; hair analysis as a tool of clinical diagnosis; hair analysis for compliance monitoring.