Medication Overuse Headaches

Medication Overuse Headaches
Natalie Roy, PharmD, MHealth Neurology Clinic 

Background: It is widely accepted that abortive medications for acute headache relief can worsen headaches if used too often. The International Headache Society (IHS) categorizes medication overuse headache (MOH) types within the International Classification of Headache Disorders (ICHD). There are diagnostic criteria for various MOH types based on pharmacotherapy used; however, there is little consensus on the duration of use, amount, and type of medication needed to cause MOH.

We do not have definitive studies showing causality between high doses of abortive agents and worsening headaches, so a common conservative recommendation is to limit treatment to no more than 10 to 15 days per month to prevent headache frequency progression. In addition, medication withdrawal is often recommended as a first step in the treatment of frequent headaches. A recent article in Neurology questioned existing data regarding overuse of medications for headaches with the uncertainty that withdrawing these medications from people with frequent headaches solely to prevent or treat medication overuse headaches may be inappropriate.

Evidence: The argument presented by the recent Neurology article included evidence from studies focused on MOH. One longitudinal population-based study followed individuals with episodic migraines for a year and compared the types of medication used, frequency of medication used, and the frequency of headaches. After controlling for sex, headache frequency and severity, and preventive medication use, researchers  found that people with episodic migraines who used medication containing opioids or barbituates were more likely to progress to chronic migraine than the reference group of acetaminophen users. Frequency of medication use by itself was not associated with chronic migraine incidence after controlling for headache frequency, although there was a dose-response relationship for frequency of use of barbiturates.

In addition, four studies considered whether MOH occurs when pain medications are used for other conditions. Two of these studies concluded that there was no association between regular or frequent use of medication for nonheadache pain and the development of chronic headache. The other two studies concluded that frequent analgesic use for nonheadache pain was associated with the development of chronic migraine only in those with a preexisting history of migraine.

On the other hand, others argue that evidence shows that the majority of patients with MOH improve after discontinuation of the overused medication, as does their responsiveness to preventative treatment.  In addition, there have been studies looking at the importance of support for patients during medication withdrawal: one study showed that patients who received support from a headache nurse showed an increased chance of successful withdrawal from medications compared to those without support.

Discussion:

The existence of MOH as a diagnostic category and as a potentially modifiable risk factor for headache chronification is well recognized by most headache specialists. However, the concept of MOH and its treatment has been uncomfortable for clinicians as the advice to patients to minimize or discontinue their most needed and likely safest medication is counterintuitive and seems to contradict the goal of minimizing pain.

It is difficult to truly study the effects of medication overuse. This type of study would require randomly assigning individuals to overuse or not overuse medication and compare rates of headache progression in the two groups. However, this would be unethical. Observational studies that show an association between frequency or type of medication used and worsening headache can provide useful prognostic information, but cannot answer the question of whether the association is bidirectional. Increased attention to this clinical gray area topic, more research, and available resources to patients and practitioners would be helpful.

Clinical Impact: The topic of MOH has provoked passionate debate among clinicians for years. There is conflicting evidence on appropriate management strategies. In order to best assess and treat patients with MOH, we should consider that characterization of frequently recurring headaches generally requires a headache diary to record information on pain and associated symptoms on a daily basis for at least a month. Sample diaries are available athttp://www.i-h-s.org. Shared decision-making models and a team-based approach are necessary in treating patients with MOH.

References:
1.     Scher AI, Rizzoli PB, Loder EW. Medication overuse headache: An entrenched idea in need of scrutiny. Neurology. 2017;89(12):1296-1304.

2.     Louter MA, Robbins MS, Terwindt GM. Medication overuse headache: An ongoing debate. Neurology. 2017;89(12):1206-1207.

3.     The International Classification of Headache Disorders, 3rd edition (beta version). Cephalalgia. 2013;33(9):629-808.

4.     Pringsheim T, Davenport WJ, Marmura MJ, Schwedt TJ, Silberstein S. How to Apply the AHS Evidence Assessment of the Acute Treatment of Migraine in Adults to your Patient with Migraine. Headache. 2016;56(7):1194-200.