Symptoms
Medication-overuse headache, depending on the preexisting symptoms, manifests, for example, like a tension headache as bilateral, pressing pain, or like a migraine, unilateral, pulsating, and accompanied by nausea, vomiting, and sensitivity to light and noise. The pain occurs chronically for at least 15 days of the month, every other day or daily. When the medication is discontinued, withdrawal symptoms such as nausea and withdrawal headaches may occur. This is another reason why dependence on the medication is often observed. Possible complications include side effects of the medication such as stomach ulcers when taking NSAIDs. Link: Detailed IHS Classification
Causes
The cause of headache is persistent use of medications for headache for more than 3 months on more than 10-15 days per month. Triggering medications include triptans, ergot alkaloids, and opioids such as codeine, in addition to nonsteroidal anti-inflammatory drugs and acetaminophen. Today, many cases are observed with triptans in the context of migraine therapy. The decisive factor is the regular intake of the medication on several days per week and the connection between the intake and the symptoms. Combination preparations containing psychotropic substances such as caffeine, barbiturates and antihistamines are also considered particularly risky. In many countries, many of these preparations have been taken off the market as part of the “group review of analgesics”, but some remain on the market. Headache occurs in predisposed patients only when the drugs are administered for headache, not when they are used, for example, for back or joint pain. The term “medication overuse headache” (MOH) was newly introduced by the International Headache Society in 2004 because the previous term “medication-induced headache” had not proved useful. This is because many drugs can also cause headache as an acute adverse effect. Well-known examples include organic nitrates and proton pump inhibitors.
Treatment
For treatment, patients undergo outpatient detoxification in mild cases and inpatient detoxification in a clinic in severe cases. “Cold turkey” withdrawal, i.e., immediate discontinuation of the causative drugs, is usually considered the method of choice (exceptions: opioids, barbiturates, benzodiazepines). Therapy must take place under medical supervision because withdrawal symptoms may occur during several days and must be adequately treated. These include withdrawal headaches, nausea, vomiting, low blood pressure, rapid pulse, sleep disturbances, anxiety, and nervousness. Seizures and hallucinations are rarely observed.
Prevention
For prevention, it is advised to avoid combination drugs and prefer monopreparations. Limiting medication use for headache is considered central (eg, taking less than 10 days per month). Medication and nonmedication preventive measures are available as adjuvants, for example, amitriptyline and relaxation techniques for tension headache or topiramate for migraine prophylaxis.
