Medication overuse headache (MOH) is defined as daily or near-daily headache (more than 15 per month) that occurs in patients with a primary headache disorder who overuse acute medications. This definition is from the Headache Classification Committee of the International Headache Society. Tolerance or resistance to medication may lead to a patient increasing amount of medication used, thus showing withdrawal symptoms upon discontinuing the overused medication.
According to data from a physician survey published in the periodical Headache in 1996, MOH may be the third most frequent type of headache after migraine and tension-type headaches.
The question remains unanswered as to the relationship of MOH and CDH. Is the increased frequency/and or severity of headache due to medication overuse, or is medication overuse a result of a gradual increase in headache frequency/and or severity?
Medication overuse headache has a greater impact on an individual’s daily functioning than does episodic migraine. Additionally patients with MOH have higher emotional distress compared with those with episodic migraine.
A study published in the November 2008 issue of Cephalalgia discusses the classification of medication overuse and medication overuse headache. All three of the following criteria must be met:
1. Headache present more than 15 days per month.
2. Regular overuse for more than 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 more than 10 days per month on a regular basis for more than 3 months.
b. Simple analgesics or any combination of ergotamine, triptans, analgesics, opioids 15 days per month on a regular basis for three months, without overuse of a single class alone.
3. Headache has developed or markedly worsened during medication overuse.
Some factors that lead to the development of MO include the desire to relieve pain; fear/anxiety in anticipation of pain; withdrawal headache; psychiatric comorbidities (major depression, anxiety) and substance abuse disorder. The best way to prevent MOH and MO is to increase awareness and to use preventive strategies. Patients need to be informed on the appropriate use of their medications and potential risks of developing MOH. Diagnosis of MOH does depend on the history that is provided by the patient. It is imperative that the patient be open and honest with the physician regarding their true consumption of medications.
If MOH is diagnosed, withdrawal of the overused medications may help reduce headache severity and frequency but is often associated with relapse; the clinician must deal with potential recurrences of MO while effectively treating the underlying primary headache disorder over the long term.
Behavioral therapy (biofeedback, relaxation, cognitive behavioral therapy) is effective in the management of migraine and may also help in the management of headaches complicated by MO. Patients who received biofeedback assisted relaxation in addition to pharmacological therapy fared better at the 3 year mark than those being treated with pharmacological therapy alone.
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 behavioral therapy may help improve clinical outcome.