A retrospective long-term analysis of the epidemiology and features of drug-induced headache.

Drug-induced headache is well known to result from the abuse of compounds taken for the treatment of primary headache. The features of drug-induced headache depend on various features including the availability of drugs, the regional health system, and psychogenic factors of the patients. We performed a retrospective study on a series of 257 consecutive German patients presenting with drug-induced headache during the period 1983-1996. Our aim study was to evaluate the demographic features, the frequency of various drugs used, in particular of ergotamine derivates, and changes in these features during the study period. The frequency of drug-induced headache among all headache patients was 8%, with a female preponderance of 81%. Drug-induced headache occurred in all age groups, predominantly in migraine patients (35%). The mean number of substances used was 2.7, mainly, acetaminophen (47.9%), ergotamine tartrate (45%), and combined analgesics (56%). We did not find a significant difference between the associations with ergotamine tartrate and dihydroergotamine, although the latter was taken less frequently. Comparing the early and late years of our study period, there were no changes in the frequency of drug-induced headache (8% versus 7%), although changes in the frequency of some drugs changed (barbiturates, ergotamine tartrate, and codeine intake decreased whereas nonsteroidal anti-inflationary drugs, combined analgesics, and sumatriptan intake increased). Our data suggest that changes in drug availability and the introduction of classification criteria and treatment recommendations did not have a major impact on the frequency of drug-induced headache.