Medication-overuse headache: similarities with drug addiction

Drug consumption in medication overuse headache is influenced by brain-derived neurotrophic factor Val66Met polymorphism

Medication overuse headache (MOH) can be considered a clinical condition at the boundaries between drug addiction and chronic pain disorder. The common 196G > A single-nucleotide polymorphism of BDNF gene, resulting in a valine 66 to methionine (Val66Met), is related with behaviour disorders and substance abuse. With the aim of identifying a worsening factor in MOH, rather than the detection of a specific risk factor for the development of the disease, we investigated whether the presence of a functional BDNF polymorphism might determine clinical differences within a group of 90 MOH patients, particularly in monthly drug consumption, that is the hallmark of disease. Directly comparing MOH patients homozygous for G allele (G/G) with carriers of A allele (non-G/G), we have observed 47 G/G genotypes and 60 non-G/G genotypes. Non-G/G had a higher consumption of monthly drug number (Cohen’s d = 0.76) than G/G patients. At multiple regression analysis, the Val66Met BDNF polymorphism emerged as a significant independent predictor of analgesic drug consumption (Beta = 0.33, Cohen’s f² = 0.134). These findings showed an influence of examined BDNF polymorphism in the MOH clinical features, supporting the idea that MOH is a substance abuse disorder.

Medication overuse headache: awareness, detection and treatment

Episodic migraine is a disabling painful disease that can affect the normal function of daily routine activities such as performance at work and school, and home and social relationships. In addition to the physical disability during migraine, between attacks many patients experience a condition referred to as interictal burden, which can present as pre-event worry about future attacks and can result in the anticipatory use and/or overuse of acute care medications. The overuse of medication can often lead to medication overuse headaches (MOHs) and chronic migraine. Unfortunately, patients, and even some physicians, are often unaware of this phenomenon. Therefore, it is important for knowledgeable physicians to raise awareness and to address the risks of medication overuse with their patients through effective communication. Future management of medication overuse should include detoxification and a comprehensive programme that includes the use of preventive medications such as sodium valproate (divalproex sodium) and topiramate in order to reduce dependency on acute care medication. Also, MOHs may be most effectively managed with the initiation of preventive treatment prior to detoxification, in addition to the decreased use of acute care medication. A long-term treatment plan, including behavioural therapy, migraine preventive medication and appropriate acute care therapy, may be optimal in treating patients with MOHs.

Involvement of Corticotrophin-Releasing Factor and Orexin-A in Chronic Migraine and Medication-Overuse Headache: Findings From Cerebrospinal Fluid

The study set out to investigate the role of corticotrophin-releasing factor (CRF) and orexin-A in chronic migraine (CM) and medication-overuse headache (MOH). Twenty-seven patients affected by CM and 30 with MOH were enrolled. Control CSF specimens were obtained from 20 age-matched subjects who underwent lumbar puncture for diagnostic purposes, and in all of them CSF and blood tests excluded central nervous system or systemic diseases. Orexin-A and CRF were determined by radioimmunoassay methods. Significantly higher levels of orexin-A and CRF were found in the CSF of MOH and to a lesser extent in patients with CM compared with control subjects (orexin-A: P < 0.001 and P < 0.02; CRF: P < 0.002 and P < 0.0003). A significant positive correlation was also found between CSF orexin-A values and those of CRF ( R = 0.71; P < 0.0008), monthly drug intake group ( R = 0.39; P < 0.03) and scores of a self-completion 10-item instrument to measure dependence upon a variety of substances, the Leeds Dependence Questionnaire (LDQ) in the MOH group ( R = 0.68; P < 0.0003). The significantly higher orexin-A levels found in CM and MOH can be interpreted as a compensatory response to chronic head pain or, alternatively, as an expression of hypothalamic response to stress due to chronic pain. A potential role for orexin-A in driving drug seeking in MOH patients through activation of stress pathways in the brain can also be hypothesized.

Prescription of medicines by medical students of Karachi, Pakistan: a cross-sectional study

BACKGROUND

Prescription of medicines by non-doctors is an issue with serious global implications. To our knowledge prescription of drugs by medical and non-medical students has not been studied before. We aimed to determine the practice and attitudes of drug prescription by medical students and: a) how non-medical students respond to this practice, b) How this compares with the attitudes and practices of non-medical students.

METHODS

A cross-sectional study was conducted on a sample of 600 students randomly selected from 2 medical and 2 non-medical universities. Ethical requirements were ensured and data was collected using self administered questionnaires. The Chi square tests and logistic univariate regression analyses were performed using SPSS v 14 to identify associations and differences.

RESULTS

A total of 572 forms were completed and the sample consisted of 295 medical students and 277 non-medical students with no significant difference in their demographic profile. Of the 295 medical students 163 (55.3%) had prescribed a medicine independently and most (48.5%) said that they did this 2-3 times a year. The commonest reasons for this were 'previous experience' (68.7%), 'problem too trivial' (34.4%) and 'we knew everything about the condition' (31.3%). One-third (33.6%) of the undergraduate medical students thought that it was alright to independently diagnose an illness while a vast majority (78.3%) thought that it was alright for them to prescribe medicines to others. Common prescriptions were pain-killers, antipyretics, antiallergics and antibiotics. Medical students who prescribed medicines were of lesser age (CI = 1.366-1.887) and more likely to belong to the 1st (CI = 3.588-21.731), 2nd (CI = 2.059- 10.869) or 3rd (CI = 4.331-26.374) year of medical college. One-third (33.9%) of the non-medical students reported that a medical student had prescribed medicines to them and 21.3% said that they trusted medical students and would follow their advice blindly. Many students thought it alright for medical students to diagnose and treat illnesses. A similar proportion of non-medical students (58.5%) reported prescribing medicines to others.

CONCLUSION

Prescription of medicines by non-doctors is rampant and urgent corrective measures are warranted. We have highlighted areas for future research and intervention and have given a few recommendations.

Degradation of endocannabinoids in chronic migraine and medication overuse headache

Chronic migraine (CM) is frequently associated with medication overuse headache (MOH). The endocannabinoid system plays a role in modulating pain including headache and is involved in the common neurobiological mechanism underlying drug addiction and reward system. Anandamide (AEA) and 2-arachidonoylglycerol are the most biologically active endocannabinoids, which bind to both central and peripheral cannabinoid receptors. The level of AEA in the extracellular space is controlled by cellular uptake via a specific AEA membrane transporter (AMT), followed by intracellular degradation by the enzyme AEA hydrolase (fatty acid amide hydrolase, FAAH). AMT and FAAH have also been characterized in human platelets. We assayed the activity of AMT and of FAAH in platelets isolated from four groups of subjects: MOH, CM without MOH, episodic migraine and controls. AMT and FAAH were significantly reduced in CM and MOH, compared to either controls or episodic migraine group. This latter finding was observed in both males and females with CM and MOH. Changes observed in the biochemical mechanisms degrading endogenous cannabinoids may reflect an adaptative behaviour induced by chronic headache and/or drug overuse.

Behavioral dependence in patients with medication overuse headache: a cross-sectional study in consulting patients using the DSM-IV criteria

OBJECTIVE

The aim of this study was to assess behavioral dependence on migraine abortive drugs in medication-overuse headache (MOH) patients and identify the predisposing factors.

BACKGROUND

It is common occurrence that MOH patients relapse after medication withdrawal. Behavioral determinants of medication overuse should therefore be identified in MOH patients.

METHODS

This was a cross-sectional, multicenter study that included 247 MOH patients (according to International Classification of Headache Disorders, 2nd edition criteria) consulting in French headache specialty centers. Face-to-face interviews were conducted by senior neurologists using a structured questionnaire including the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) criteria for the evaluation of dependence, Hospital Anxiety and Depression Scale for the evaluation of anxiety and depression, and 6-item short-form Headache Impact Test scale for the determination of functional impact.

RESULTS

Most MOH patients had pre-existing primary migraine (87.4%) and current migraine-type headaches (83.0%). Treatments overused included triptans (45.8%), opioid analgesics alone or in combination (43.3% of patients), and analgesics (27.9%). Nonmigraine abortive substances (tobacco, caffeine, sedatives/anxiolytics) were overused by 13.8% of patients. Two-thirds of MOH patients (66.8%) were considered dependent on acute treatments of headaches according to the DSM-IV criteria. Most dependent MOH patients had migraine as pre-existing primary headache (85.7%) and current migraine-type headaches (87.9%), and most of them overused opioid analgesics. More dependent than nondependent MOH patients were dependent on psychoactive substances (17.6% vs 6.1%). Multivariate logistic analysis indicated that risk factors of dependence on acute treatments of headaches pertained both to the underlying disease (history of migraine, unilateral headaches) and to drug addiction (opioid overuse, previous withdrawal). Affective symptoms did not appear among the predictive factors of dependence.

CONCLUSION

In some cases, MOH thus appears to belong to the spectrum of addictive behaviors. In clinical practice, behavioral management of MOH should be undertaken besides pharmacological management.

The wolframin His611Arg polymorphism influences medication overuse headache

Homozygosis for wolframin (WFS1) mutations determines Wolfram syndrome (WS), and common polymorphisms of WFS1 are associated with psychiatric illnesses and dependence behaviour. To test the influence of WFS1 polymorphisms on medication overuse headache (MOH), a chronic headache condition related to symptomatic drugs overuse, we analyzed 82 MOH patients for the WFS1 His611Arg polymorphism, and performed a comparison between clinical features of Arg/Arg (R/R) and non-R/R individuals. Individuals harbouring the R/R genotype showed significantly higher monthly drug consumption (t=-3.504; p=0.00075) and more severe depressive symptoms on the BDI questionnaire (t=-3.048; p=0.003) than non-R/R. WFS1 polymorphism emerged as the only significant predictor of drug consumption, at the multivariate regression analysis (F=12.277; d.f.=1,80; p=0.00075, adjusted R2=0.122). These results implicate WFS1 in the clinical picture of MOH, may be through an influence on need for drugs as in other conditions of abuse behaviour.

Endocannabinoids in chronic migraine: CSF findings suggest a system failure

Based on experimental evidence of the antinociceptive action of endocannabinoids and their role in the modulation of trigeminovascular system activation, we hypothesized that the endocannabinoid system may be dysfunctional in chronic migraine (CM). We examined whether the concentrations of N-arachidonoylethanolamide (anandamide, AEA), palmitoylethanolamide (PEA), and 2-arachidonoylglycerol (2-AG) in the CSF of patients with CM and with probable CM and probable analgesic-overuse headache (PCM+PAOH) are altered compared with control subjects. The above endocannabinoids were measured by high-performance liquid chromatography (HPLC), and quantified by isotope dilution gas-chromatography/mass-spectrometry. Calcitonin gene-related peptide (CGRP) levels were also determined by RIA method and the end products of nitric oxide (NO), the nitrites, by HPLC. CSF concentrations of AEA were significantly lower and those of PEA slightly but significantly higher both in patients with CM and PCM+PAOH than in nonmigraineur controls (p<0.01 and p<0.02, respectively). A negative correlation was found between AEA and CGRP levels in CM and PCM+PAOH patients (r=0.59, p<0.01 and r=-0.65, p<0.007; respectively). A similar trend was observed between this endocannabinoid and nitrite levels. Reduced levels of AEA in the CSF of CM and PCM+PAOH patients may reflect an impairment of the endocannabinoid system in these patients, which may contribute to chronic head pain and seem to be related to increased CGRP and NO production. These findings support the potential role of the cannabinoid (CB)1 receptor as a possible therapeutic target in CM.

Antiepileptic drugs in migraine: from clinical aspects to cellular mechanisms

Migraine and epilepsy share several clinical features, and epilepsy is a comorbid condition of migraine. Clinical studies have shown that some antiepileptic drugs are effective at preventing migraine attacks. A rationale for their use in migraine prophylaxis is the hypothesis that migraine and epilepsy share several common pathogenetic mechanisms. An imbalance between excitatory glutamate-mediated transmission and GABA-mediated inhibition in specific brain areas has been postulated in these two pathological conditions. Moreover, abnormal activation of voltage-operated ionic channels has been implicated in both migraine and epilepsy. Cortical spreading depression has been found to be involved in the pathophysiology of epilepsy, in addition to the generation of migraine aura.

Orbitofrontal cortex involvement in chronic analgesic-overuse headache evolving from episodic migraine

The way in which medication overuse transforms episodic migraine into chronic daily headache is unknown. To search for candidate brain areas involved in this process, we measured glucose metabolism with 18-FDG PET in 16 chronic migraineurs with analgesic overuse before and 3 weeks after medication withdrawal and compared the data with those of a control population (n = 68). Before withdrawal, the bilateral thalamus, orbitofrontal cortex (OFC), anterior cingulate gyrus, insula/ventral striatum and right inferior parietal lobule were hypometabolic, while the cerebellar vermis was hypermetabolic. All dysmetabolic areas recovered to almost normal glucose uptake after withdrawal of analgesics, except the OFC where a further metabolic decrease was found. A subanalysis showed that most of the orbitofrontal hypometabolism was due to eight patients overusing combination analgesics and/or an ergotamine-caffeine preparation. Medication overuse headache is thus associated with reversible metabolic changes in pain processing structures like other chronic pain disorders, but also with persistent orbitofrontal hypofunction. The latter is known to occur in drug dependence and could predispose subgroups of migraineurs to recurrent analgesic overuse.

Does medication overuse headache represent a behavior of dependence?

Medication overuse is relatively common in patients with frequent headache. To explore the prevalence of patients who meet the criteria for substance dependence in Diagnostic and Statistical Manual of Mental Disorders, Edition IV (DSM-IV), and to identify variables of substance dependence among patients with chronic daily headache, we recruited consecutive patients with chronic daily headache at a headache clinic from November 1999 to June 2004. Each patient completed a headache intake form, a dependence questionnaire modified from DSM-IV, and the Hospital Anxiety and Depression Scale (HADS). The presence of probable medication overuse headache (pMOH) was defined on the basis of the International Classification of Headache Disorders, 2nd edition, 2004. A total of 1,861 patients with chronic daily headache (1,369 women, 492 men; mean age, 49.6+/-15.4 years) were recruited. Almost half (895/1,861, 48%) met criteria of pMOH, and 606 of these patients (606/895, 68%) met three of five DSM-IV substance dependence criteria. In contrast, only 191 of 968 patients without pMOH (20%) met the DSM-IV criteria (OR=8.6, [7.0-10.6], chi-square test, P<0.001). Patients who fulfilled DSM-IV criteria of dependence had higher numbers of physician appointments in the past year. Multivariate logistic regression analyses revealed that migraine headache, frequent physician consultation, intensity of headache, and presence of a higher anxiety score were significant independent variables for substance dependence. Among patients with chronic daily headache, pMOH was associated with behaviors of substance dependence.