When the treatment becomes the headache

Definition and impact of MOH

The current ICHD-3 criteria¹ define MOH as:

• Headache occurring on 15 days/month in a patient with a pre-existing primary headache disorder
• Regular overuse for >3 months of ≥1 drugs that can be taken for acute and/or symptomatic treatment of headache
• Not better accounted for by another ICHD-3 diagnosis

Migraine is the primary headache disorder in up to 80%³. Patients overuse medication in an attempt to alleviate the symptoms of their primary headache, and an unfortunate cycle results whereby the treatment becomes the cause of the headaches.

MOH has a greater impact on patients and society than that of migraine alone

MOH is a major and growing public health concern², with a greater impact on patients and society than that of migraine alone. It most commonly affects women in their 40s², and prevalence decreases with older age². Other associated factors include obesity, physical inactivity and smoking⁴.

What is the cause of MOH?

There are functional and structural changes in the central nervous system

The pathophysiology of MOH is complex and only partly understood. Studies have shown functional and structural changes in the central nervous system⁵. Candidate polymorphic gene variants are being explored, and proposed mechanisms include altered neurotransmitter metabolism and upregulation of vasoactive and proinflammatory mediators (eg calcitonin gene‑related peptide [CGRP])⁵.

Prevention through education

MOH is preventable, and requires increased awareness in the general population, and all healthcare professionals dealing with patients with headaches. Only 8% of patients know that overuse of all types of headache medications can lead to the development of MOH⁶.

MOH is preventable and requires increased awareness

Education and counselling, to limit future acute medication use, can be effective in patients with simple MOH, but is usually not sufficient in those patients with more complex MOH⁴. This includes opioid/tranquiliser/barbiturate overuse, and those with behavioural and co-morbid psychiatric conditions.

Managing overuse drug withdrawal

If education is not effective then the next step is withdrawal from the overused drugs⁴, to restore an episodic pattern of headache. There is considerable debate on mode of withdrawal and use of bridging treatments⁴. Drug intake can generally be abruptly terminated in patients overusing simple analgesics/ergots/triptans, but slow tapering may be needed in those on opioids/barbiturates/tranquilisers⁴. Patients should be warned they may feel worse before they feel better.

Success rate for withdrawal are 50 to 70%

Withdrawal can be performed in an outpatient or inpatient setting, depending on the particular case⁴. Those with more complex MOH may need a multidisciplinary team, including neurologist/pain specialist and behavioural psychologist. Success rates are 50 to 70%⁴, with higher relapse rates in those with opioid overuse, and robust medium- to long-term follow‑up plans are important.

Preventive medication can be highly effective

Preventive plus withdrawal treatment is more effective than either alone

Preventive therapy should be offered alongside withdrawal, as this is more effective than either approach alone. Carlsen et al⁷ demonstrated that MOH cure was increased by 30% (relative risk 1.3; 1.1, 1.6) with withdrawal plus preventive compared to preventive alone (p=0.03), although all three strategies were effective, with headache days/month reduced by 12.3 in combined, 9.9 in preventive and 8.5 in withdrawal groups.

Educational financial support for this Satellite symposium was provided by Lundbeck.