Dodick D.W., Scottsdale A.Z.

How clinicians can detect, prevent and treat medication overuse headache.

This study reviews current research involving MOH and provides clinical suggestions for detecting, preventing and managing patients with MOH. Medication overuse headache (MOH) is defined as daily or near-daily headache (>15 days per month) that occurs in patients with a primary headache disorder overusing acute medications. Tolerance to the analgesic effect of the acute medication develops over time, consumption may increase and patients may show withdrawal symptoms upon discontinuing the overused medication. The prevalence of MOH in the general population worldwide is at least 1% in adults and 0.5% in adolescents. MOH may be the third most frequent type of headache after migraine and tension-type headaches. Is medication overuse (MO) the cause or the result of transformation of episodic headache disorders to forms of CDH? Is the increased frequency and/or severity of headache due to MO, or is MO a result of a gradual increase in headache frequency and/or severity? A causal relationship is suggested by studies showing that some patients with CDH revert to an episodic migraine pattern after withdrawal of the overused symptomatic medications. In addition, frequent or daily use of analgesic medications by patients for non-headache conditions can result in CDH, but only in patients with a previous history of migraine. However CDH can occur without MO and not all patients who meet criteria for MOH improve upon withdrawal of the overused medication. Standardized guidelines for the treatment of MOH are not currently available; MOH management strategies are built on the belief that patients with MOH do not respond to prophylactic medications until the overused medications are withdrawn and detoxification strategies are advocated prior to the initiation of preventive medications. However, data from recent clinical trials of preventive migraine treatment in patients with chronic migraine, including those with MO, challenge this assumption. The diagnostic classification of MOH was formally introduced in the 2004 International Classification of Headache Disorders (2nd edn) (ICHD-2) and was defined as a chronic headache that occurs following the frequent and regular use of medication for the acute treatment of headache, which resolves or reverts to its previous episodic pattern within 2 months after withdrawal of the overused medication. The mandatory requirement of headache improvement following drug withdrawal has proven problematic in clinical practice: the diagnosis could be made only in retrospect and could never be made during the initial evaluation as a withdrawal period was necessary to make the diagnosis Revisions to the MOH diagnostic criteria have recently been proposed: 1. Headache present > 15 days per month 2. Regular overuse for > 3 months of one or more acute/symptomatic treatment drugs defined as follows: a. Ergotamine, or triptans (any formulation), or opioid, or combination analgesic medication intake > 10 days per month on a regular basis b. Simple analgesics or any combination of ergotamine, triptans, analgesics, opioids 15 days per month on a regular basis, without overuse of a single class alone 3. Headache has developed or markedly worsened during medication overuse (Must have all three) The clinical features of MOH can vary, but headaches generally occur on a daily to near-daily basis. Symptoms accompanying the headache may include nausea, asthenia, restlessness, anxiety, concentration difficulties, forgetfulness and irritability. The characteristics of MOH may depend on the overused type of medication: overuse of triptans has been shown to cause MOH faster and with fewer doses compared with ergots and analgesics. The frequency of opioid overuse headache did not significantly vary over time. Whereas ergotamine tartrate is well known to cause MOH, dihydroergotamine (DHE) is not. Factors leading to the development of MO are: 1. Desire to relieve pain and continue function 2. Fear/anxiety in anticipation of pain or fear of disability (MOH is associated with considerable disability in individual’s daily functioning) 3. Withdrawal headache 4. Psychiatric comorbidities (major depression, anxiety) 5. Substance abuse disorders The goal in treating MOH is to reduce the frequency of headaches, reduce MO and improve responsiveness to acute and preventive treatments. A typical protocol includes: 1.Initiation of preventive therapy 2.Abrupt or gradual withdrawal of the overused medication (in-patient or out-patient management) 3.Initiation of therapy to treat withdrawal symptoms, including breakthrough and withdrawal headaches Once MOH is diagnosed, withdrawal of the overused medication(s) may help reduce headache severity and frequency but is often associated with relapse. Medication withdrawal strategies vary about abrupt or gradual withdrawal, inpatient or outpatient detoxification. Data from recent trials suggest that migraine preventive treatments are effective in patients with MOH prior to withdrawal of overused medications and further suggest a critical need to re-evaluate the strategies currently used for treatment of this disorder through well-designed clinical research. The best way to prevent MOH is to increase awareness of MO by effective physician–patient communication and patient education about the risks and proper use of medications and to use preventive strategies. Migraine prevention is designed to decrease the frequency of headaches and decrease the use of cute medications. Decreasing headache frequency may help ease the anxiety and worry that patients experience between attacks in relation to anticipation of future migraines and thus reduce the incentive to overuse medications. Migraine preventive medications are an important component of withdrawal treatment strategies and it is generally agreed that preventive treatment of the primary headache disorder should start as soon as possible during the withdrawal process. After the withdrawal of the overused medication, patients receiving prophylactic therapy significantly reduce headache frequency. Some preventive medications that have shown beneficial effects are Topiramate and Divalproex sodium. Physicians and patients need to be aware of MO, to be informed about the appropriate use of medication and the potential risk of developing MOH. Information to patients may include: 1. The role of MO in increasing headache frequency and severity and in potentially reducing the effectiveness of other treatments 2. The fact that MOH may occur with as few as 2–3 days of acute medication use per week 3. An explanation of the phenomenon and symptoms of withdrawal headache 4. Limits on the use of acute medications and discouraging their anticipatory use The diagnosis of MOH relies on the history that is provided by the patient: therefore, open, true and accurate communication between professionals and patients is crucial for the recognition and management of MOH. An headache diary could be useful. Advice and education about the risk of MO and its consequences may be as effective as structured in-patient and out-patient detoxification programmes in achieving withdrawal of the overused medication in patients with low medical need and some studies prove it. Non-pharmacological management of MOH is effective too: behavioural therapy (e.g. biofeedback, relaxation, cognitive behavioural therapy) helps in managing primary headaches such as migraine and may also potentially help in the management of headaches complicated by MO. Patients with MOH require a great deal of support during treatment. Regular contact with physicians, proper instruction and an interdisciplinary approach to treatment that includes behavioural therapy may help improve clinical outcome. (summary of the original article by H. Duyver)

Cephalalgia, 2008, 28, 1209-1217 (© Blackwell Publishing Ltd)