Headaches caused by medication misuse affect about 2% of the population. While a regular prescription or over-the-counter painkiller usually provides relief, excessive monthly use can actually worsen headaches over time. Dr. Erel Domany, a senior neurologist in the Department of Neurology at Rambam Health Care Campus (Rambam) in Haifa, Israel, explains the causes and effects of this phenomenon.
Dr. Erel Domany. Credit: Rambam H CC.
Everyone experiences headaches occasionally, and many suffer from migraines. However, when pain becomes so severe that patients exceed the recommended dosage of painkillers, the side effects can paradoxically lead to more frequent and intense headaches.
Fluctuating hormone levels in women can lead to headaches and migraines. A gynecologist may prescribe hormone therapy or refer a patient to a neurologist for further evaluation.
Dr. Domany, head of Rambam’s Headache Clinic, explains that medication overuse headache (MOH) is a recurring headache (occurring at least 15 days a month) caused by the overuse of painkillers. “The frequency, intensity, and duration of the headache worsen, and additional symptoms may appear,” he says. As the painkillers become progressively less effective, the patient’s symptoms intensify, creating a vicious cycle.
He emphasizes that MOH develops in individuals with primary headache conditions such as migraines, cluster headaches (intense unilateral pain around one eye), or tension headaches (which can affect up to 70% of the general population). He explains that the threshold for excessive use varies by medication type; individuals should not take painkillers like paracetamol or non-steroidal anti-inflammatories more than 15 days a month.
The overuse of medications containing caffeine, opioids, or migraine drugs is defined as more than ten days a month, and the frequency of use is more critical than the daily dosage. Domany explains that MOH is caused by the brain’s sensitization mechanism, not by addiction. “Frequent attempts to block pain signals in the brain with painkillers result in increased signal transmission and a lower pain threshold,” he adds.
Lack of Awareness
Medication overuse headache affects 1-2% of the population in Europe, the U.S., and non-Western countries. “There hasn’t been insufficient research into its prevalence in Israel,” Domany elaborates. “Neurologists don’t always recognize the condition, and those who do sometimes lack a full understanding of the mechanism. They may advise patients to try different medications, but this isn’t a solution and prolongs their suffering.” In Israel, only a few headache specialists can diagnose and treat the condition optimally, as no formal training is available here. Training is available abroad, but few doctors pursue it.”
Several countries are trying to combat this phenomenon; Denmark for instance successfully raised community health and public awareness through lectures, advertisements, and brochures, reducing the prevalence of MOH by 50% in one year.
Treating Medication Overuse Headache
An accurate diagnosis of the primary headache is the first step toward successful treatment. “We start with preventative treatment for the primary headache, but the chances of success are often low,” says Domany. “In such cases, we initiate painkiller withdrawal, which involves complete avoidance of any painkiller for a specific period.
During withdrawal, patients may experience worsening symptoms—migraines may develop together with nausea and vomiting, and other withdrawal effects. The process can last a week or more, and medication to manage these side effects may be administered orally or intravenously. “After a few weeks, the patient is reassessed. If MOH symptoms persist, we tailor a treatment plan to prevent further overuse,” Domany explains.
Domany emphasizes the importance of recognizing the early symptoms of MOH. “Most people don’t track their painkiller intake, but needing to buy more within a short period is a clue. Increased headache frequency and intensity, new symptoms, or reduced effectiveness are red flags that require specialized attention.”
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