[Headache caused by analgesic and/or ergotamine abuse]

Abstract

Headache induced by ergotamine-abuse was described 40 years ago. More recently there is ample evidence suggesting that chronic headache may also be provoked by analgesic abuse. A recent Classification of the International Headache Society has defined this kind of headache as an autonomous disease. It consists in a daily chronic headache with paroxysmal attacks associated with daily or almost daily assumption of analgesics and/or ergotamine. It is debated whether the term "abuse" or "dependence" is correct. Almost 5% of patients of the Headache Centres in Italy were found to be drug abusers. Most of these patients originally suffered from migraine. The therapeutic approach consists in hospitalization, withdrawal of analgesics and/or ergotamine, treatment of the withdrawal headache (which appears within 48 hours and lasts even 1-2 weeks) and finally in a prophylactic therapy. Although several treatments have been suggested for the abstinence syndrome, only fluid replacement, antiemetics, hypnotic-sedative drugs and rarely mild analgesics are necessary. A review of the literature shows the following success rates in the relief of the headache: above 50% relief in more than 60% of patients within a follow up period of 1 to 3.5 years as mean. Even if caffeine and barbiturates, which are often contained in the analgesic and ergotamine preparations, might be considered the cause of the abuse and withdrawal syndrome, they don't seem to play a fundamental role in this syndrome. An impairment of the central antinociceptive system was hypothesized to be involved in the pathogenesis of the headache associated with analgesic and/or ergotamine abuse. Recently there has been evidence of a possible hyposensitivity of the adrenergic and serotoninergic receptors of the central nervous system. It is still to be proved whether drug abuse is the cause or the consequence of the headache chronicization. The remarkable improvement of headache after analgesic withdrawal suggests a causal factor.