Monitoring of adherence to headache treatments by means of hair analysis

Abstract

Purpose: The aim of this study was to evaluate the potential of hair analysis to monitor medication adherence in headache patients undergoing chronic therapy. For this purpose, the following parameters were analyzed: the detection rate of 23 therapeutic drugs in headache patients' hair, the degree of agreement between the self-reported drug and the drug found in hair, and whether the levels found in hair reflected the drug intake reported by the patients.

Methods: The study included 93 patients suffering from primary headaches declaring their daily intake of at least one of the following drugs during the 3 months before the hair sampling: alprazolam, amitriptyline, citalopram, clomipramine, clonazepam, delorazepam, diazepam, duloxetine, fluoxetine, flurazepam, levomepromazine, levosulpiride, lorazepam, lormetazepam, mirtazapine, paroxetine, quetiapine, sertraline, topiramate, trazodone, triazolam, venlafaxine, and zolpidem. A detailed pharmacological history and a sample of hair were collected for each patient. Hair samples were analyzed by liquid chromatography-electrospray tandem mass spectrometry, using a previously developed method.

Results: All 23 drugs were detected in the examined hair samples. The agreement between the self-reported drug and the drug found in hair was excellent for most analytes (P < 0.001, Cohen's kappa); a statistically significant relationship (P < 0.05, linear regression analysis) between dose and hair level was found for amitriptyline, citalopram, delorazepam, duloxetine, lorazepam, and venlafaxine.

Conclusions: Hair analysis proved to be a unique matrix to document chronic drug use in headache patients, and the level found for each individual drug can represent a reliable marker of adherence to pharmacological treatments.

Keywords: Adherence; Drug treatment; Hair analysis; Headache; Monitoring; Prophylaxis.

Conflict of interest statement

The authors declare that they have no conflict of interest. Ethical approval The study was approved by the Ethical Provincial Committee of Modena (Prot. n. 3610/C.E., file 126/13) and conducted in compliance with the latest version of the Declaration of Helsinki. Informed consent All the patients gave their written consent to their participation in the study. Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Figures

Fig. 1

Relationship between cumulative dose of the drugs taken in the previous 3 months and their concentration in hair [diamond data points, line linear regression; the fitted line has only been reported when the regression coefficient was statistically significant (P < 0.05); r = slope value]