Abuse liability of centrally acting non-opioid analgesics and muscle relaxants--a brief update based on a comparison of pharmacovigilance data and evidence from the literature.
BACKGROUND AND OBJECTIVE The abuse pattern of analgesics is not well known in persons with "chronic daily headache and analgesic abuse" (CHA) in the general population. The objective of this study was to know the type of analgesics used by pharmacological group and the active ingredient in subjects with CHA in a large sample of the general population. PATIENTS AND METHODS A questionnaire was distributed that investigated the frequency of headache and analgesic consumption among persons over 14 years (9,984 inhabitants) of the semiurban population of Santoña (Cantabria). A total of 4,855 subjects filled out the questionnaire. Although the CHA criteria require headache > or = 15 days a month, those individuals (n = 332) that report subjective consumption of analgesics for headache > or = 10 days in this period filled out a headache diary for one month. A total of 72 individuals fulfilled CHA criteria (1.48% of the general population). The varieties of CHA were classified according to the Silberstein et al criteria. RESULTS The greatest consumption corresponded to the simple analgesic group with 34.7% of all the subjects followed by those of combined analgesics and ergotaminics consumed by 27.8% and 22.2% respectively. A total of 12.5% took opioids alone or associated and triptans were in the fifth place. The latter were consumed by 2.8% of all the subjects. The active ingredients used most were: paracetamol (54%), caffeine (49%), ergotic derivatives (38%) and propyphenazone (35%). The subjects detected consumed a mean of 2.5 active ingredients simultaneously. The mean units consumed in their different presentation by the subjects with CHA was 50 units/month. CONCLUSIONS This study shows that CHA is a significant health care problem. In our setting, 85% of the persons with CHA of the population used analgesics and/or ergotics. These medications were given without prescription so that their obtention should be regulated in the pharmacy offices.