Human scalp hair as evidence of individual dosage history of haloperidol: method and retrospective study

Abstract

Hair samples and morning pre-dose plasma were collected from 40 patients who had received fixed daily doses of haloperidol for more than four months and whose compliance was good. After washing, 1 to 2 cm-long portions nearest to the roots of 2 to 3 strands of hair were completely dissolved in 2.5N NaOH. Haloperidol in that sample or alkalinised plasma was extracted and measured by RIA. Haloperidol concentrations in hair correlated well both with the trough concentration in plasma at steady-state (r = 0.772, n = 39) and with the daily dose (r = 0.555, n = 40). Another keratinized tissue, nail, was also collected from 20 of the 40 patients and the haloperidol level was compared with that in hair. The former was only about 4.3% of the latter and was significantly correlated only with the daily dose (r = 0.525, n = 20). Hair from 10 other patients in whom the dosage of haloperidol had been changed within a few months prior to sampling the hair was cut into 0.5 or 1 cm-long portions from the roots and the drug concentration in each portion was measured. If hairs were assumed to grow at 1 cm/month, a history of individual dosage could be deduced in 9 of the 10 patients from the distribution of drug level along the length of the hair. The results suggest that human scalp hair could serve as a useful tool for monitoring individual dosage history over several months, or in demonstrating exposure or non-exposure of a patient to a drug.

Assessing the potential of a “color effect” for hair analysis of 11-nor-9-carboxy-Δ9-tetrahydrocannabinol: Analysis of a large sample of hair specimens

“…In addition to the use of hair assays for the identification of illicit psychoactive drug use, it has also been applied to a variety of medicinals, such as antibiotics, antipsychotics, and anti-epileptics (Uematsu et al, 1989;Mieczkowski, 2000;Mieczkowski et al, 2001). Also, it has become a frequently used method for assessing compliance to drug abstinence requirements in such programs as driver's license restoration (Mangin, 1995) various drug abuse disciplinary actions (Knight, 1998), and testing of sensitive employment positions (Cook, 1997).…”

Hair Analysis as Method for Determination of Level of Drugs and Pharmaceutical in Human Body: Review of Chromatographic Procedures

“…Several therapeutic, but potentially toxic, drugs such as antidepressants, antipsychotics, and tranquillizers have been determined in hair, for tricyclic and tetracyclic antidepressant readers can refer to the papers by Couper et al (1995a, b) and for haloperidol to the papers by Uematsu et al (1989) and Matsuno et al (1990). Research on benzodiazepine analysis in hair has also been published (Toyo'oka et al 2003;Kangas 1979;Höld et al 1997).…”

The measurement of haloperidol and reduced haloperidol in hair as an index of dosage history.

“…The dilution of antiserum which exhibited 50% binding to the labelled antigen was 1:4500, showing an appropriately high affinity for haloperidol. The procedures for measuring haloperidol in hair with the radioimmunoassay are described in detail elsewhere (Uematsu et al, 1989). Cross-reactivities of haloperidol with its major metabolites have been reported to be less than 0.1% (Suzuki et al, 1980).…”

“…Our purpose was to correlate quantitively the content of drug and metabolite in hair with the dose and with steady-state plasma drug concentrations in order to use the analysis of hair for therapeutic drug monitoring. In a previous communication (Uematsu et al, 1989) we suggested that hair might be superior to plasma for the therapeutic drug monitoring of haloperidol because the concentration of haloperidol in hair correlated with daily dosage while the trough plasma concentration of haloperidol, which is usually employed for routine therapeutic drug monitoring, did not represent the daily dose. Again in the present study, which used a larger number of patients, the trough plasma concentration of haloperidol did not correlate significantly with daily dose, while the concentration of haloperidol and reduced haloperidol in hair did.…”

“…We have been interested in the use of human scalp hair to monitor the dosage history of drugs and have shown that hair contains haloperidol corresponding to the given dose, thereby suggesting the potential usefulness of hair analysis in therapeutic drug monitoring (Uematsu et al, 1989). Haloperidol is one of the most widely used psychotropic drugs and may be administered for a long period of time.…”