<figure id="attachment_473165" class="wp-caption alignnone" style="width: 640px;" aria-describedby="caption-attachment-473165"><a href="#" data-ident_hash="50c56bdc"><img src="https://res.cloudinary.com/fridaydigital/image/private/t_article_image/wpmedia/2026/07/6670d9d61da2ee882ba085e4f5bc4dd5.jpg" alt=""></a><figcaption id="caption-attachment-473165" class="wp-caption-text">Headache medicines and painkillers are among the best-selling products at drugstores.</figcaption></figure>
As Japan&#8217;s healthcare costs continue to rise, the government has been promoting self-medication—the idea that people should manage minor health problems themselves by using over-the-counter (OTC) medicines. The approach is expected to reduce the burden on medical institutions and help curb healthcare spending.
At the same time, however, one issue that often goes overlooked is the improper use of medication based on self-diagnosis.
Drugstores stock a wide variety of headache medicines, and they can also be purchased easily online. Many people assume that because they are over-the-counter drugs, they are safe, and take them whenever they develop a headache.
In recent years, however, headache specialists and addiction specialists have become increasingly concerned about medication-overuse headache (MOH)—headaches that develop as a result of taking headache medicine too frequently.
&#8220;I&#8217;m taking painkillers, but my headaches won&#8217;t go away. In fact, they&#8217;ve become more frequent than before.&#8221; According to Dr. Satoshi Ozaki, a neurosurgeon and director of Ebina Neurosurgical Clinic, &#8220;In some cases, the headache medicine itself is the cause.&#8221;
He explained the reality of OTC drug dependence and medication-overuse headaches. (All quotations below are from Dr. Ozaki.)
<h2>Taking too many headache medicines can make headaches chronic</h2>
&#8220;Medication-overuse headache refers to headaches caused by the very medications that were originally taken to relieve them. When painkillers are used frequently, the brain becomes increasingly sensitive to pain, making headaches more likely to occur whenever the medication wears off.&#8221;
Patients generally believe, &#8220;I&#8217;m taking medicine because I have headaches.&#8221; In reality, however, many have reached a point where my headaches continue because I keep taking the medicine.
&#8220;For many over-the-counter painkillers, using them on more than 10 days per month is considered to increase the risk of medication-overuse headache.&#8221;
Many OTC headache medicines contain not only pain-relieving ingredients but also substances with sedative or stimulant effects. Among the ingredients that warrant particular attention are:
・Allylisopropylacetylurea
・Bromovalerylurea
・Anhydrous caffeine
Allylisopropylacetylurea has sedative properties and helps relieve anxiety and tension. In addition to easing pain, it can make users feel more relaxed or at ease, increasing the likelihood of psychological dependence, such as believing, &#8220;Only this medicine works for me.&#8221;
Bromovalerylurea is a sedative-hypnotic ingredient with effects similar to those of barbiturate drugs, which were once used as sleeping medications. In recent years, it has also been found in some over-the-counter medicines that have become associated with overdoses among young people, prompting addiction specialists to issue warnings.
&#8220;These ingredients do not cause dependence immediately. However, because they tend to produce a strong feeling that the medicine worked, people may gradually increase how often they take them. As a result, some eventually develop medication-overuse headaches or become dependent on over-the-counter medicines.&#8221;
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One thing that’s often overlooked is the anhydrous caffeine found in headache medicine.
 “Over-the-counter headache medications also contain anhydrous caffeine. This is because it enhances the effectiveness of the pain reliever and helps alleviate the drowsiness and fatigue associated with headaches.”
However, caution is also advised.
 “In addition to the anhydrous caffeine in headache medicine, people who drink coffee, black tea, green tea, or energy drinks may be increasing their total caffeine intake without even realizing it.”
<figure id="attachment_473530" class="wp-caption alignnone" style="width: 3024px;" aria-describedby="caption-attachment-473530"><a href="#" data-ident_hash="7352e842"><img src="https://res.cloudinary.com/fridaydigital/image/private/t_article_image/wpmedia/2026/07/7a7276b765134bb90d7dcec033ec769b.jpg" alt=""></a><figcaption id="caption-attachment-473530" class="wp-caption-text">One cup of coffee a day is generally considered an appropriate amount. Excessive intake can cause headaches.</figcaption></figure>
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Excessive caffeine consumption can lead to health problems.
&#8220;Caffeine is a familiar ingredient, but consuming too much can cause insomnia, heart palpitations, anxiety, and hand tremors. In severe cases, arrhythmias and impaired consciousness have also been reported.&#8221;
People who consume caffeine regularly may also suffer from withdrawal symptoms, such as:
・Headaches when they don&#8217;t consume it
・Severe drowsiness
・Persistent fatigue
・Reduced concentration
&#8220;These are caffeine withdrawal symptoms, and when headaches are added to the mix, many people end up trapped in a vicious cycle.&#8221;
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<h2>Over-the-counter doesn&#8217;t necessarily mean safe</h2>
Self-medication is originally intended as a way to maintain one&#8217;s health by using medicines appropriately. However, because over-the-counter drugs can be purchased without a doctor&#8217;s examination, there is a risk that people will continue taking them for long periods without determining the underlying cause of their symptoms.
&#8220;Just because a medicine is sold over the counter doesn&#8217;t mean it&#8217;s safe. If you&#8217;ve found yourself taking headache medicine more frequently, feeling anxious when you don&#8217;t have it with you, or noticing that it doesn&#8217;t work as well as it used to, I recommend visiting a headache clinic or a neurology department at least once.&#8221;
Persistent headaches may also be a sign of serious illnesses such as a stroke or a brain tumor.
&#8220;If your headaches continue, you shouldn&#8217;t simply assume they&#8217;re just headaches. Rather than continuing to take over-the-counter medicine on your own judgment, you should consult a specialist when necessary.&#8221;
You&#8217;re taking headache medicine, yet your headaches won&#8217;t go away. That may be a sign that the headache medicine itself is causing your headaches—and once that happens, the suffering can become endless. Precisely because we live in an age of self-medication, it is essential to understand how to use over-the-counter medicines properly.

 While the promotion of self-medication has made it easier to purchase medications, there has been a rise in “headaches caused by headache medicine.” A specialist also explains unexpected lifestyle habits that can trigger headaches

Can Too Many Painkillers Make Your Headaches Worse? The Truth About Medication-Overuse Headache

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