(100) Morbi-Mortality Consequences of Misuse of Psychoactive Prescription Drugs in Portugal: A Retrospective Observational Study - The MisuMedPT Project

Publication Number: 774

Background: In Portugal, there are no published data on the health-related consequences of prescription drug misuse, which is therefore a public health issue of unknown dimension in our country. Poison control centres, together with other pharmacoepidemiological sources, can be part of an active surveillance system for monitoring medicine’s misuse and drug abuse.

Objectives: To characterise calls received by the Portuguese Poison Information Centre (CIAV) reporting intentional poisonings involving at least one psychoactive medicine.

Methods: Retrospective observational study of intentional exposures to opioid analgesics, antiepileptics, anxiolytics, hypnotics and sedatives, antidepressants, psychostimulants and drugs used in opioid dependence reported to the Portuguese Poison Information Centre (CIAV) from 2014 to 2018. The variables studied were demographic characteristics of individuals, geographic distribution of calls, co-exposure to alcohol or illicit drugs, call origin, case evaluation and case guidance. Annual rates of intentional exposure based on census and medicines’ use data (sales information from HMR Portugal) were estimated.

Results: Between 2014 and 2018, 24,624 calls were received at CIAV reporting 34,203 intentional exposures to any medicinal product, with 20,906 exposures receiving emergency room visit advice or effective hospitalisation. In the 23,139 calls reporting intentional poisonings to the 69 psychoactive medicines studied, exposure was combined with alcohol or with illegal drugs in 1,918 and 117 calls, respectively. 31,169 (91.1%) intentional exposures involved one of the studied medicines, 76% of which referring to females and 46% to the 35-54 age group. The most frequently involved psychoactive medicines were benzodiazepines (62.0%), leading alprazolam (15.4%, but declining since 2015) and diazepam (12.0%), with trazodone ranking fifth (6.0%). Prescription opioids are quite underrepresented, tramadol appearing first in the 25th position of the ranking. Alprazolam has the highest rate of intentional poisoning (88.2/million inhabitants). However, considering the at-risk population (patients treated with each medicine), the rate of intentional poisoning is higher for diazepam and trazodone (in 2018, 6.12 and 5.77/1,000 patients, respectively).

Conclusions: Prescription opioids are not frequently reported in intentional poisonings, contrasting with benzodiazepines and antidepressants, the top therapeutic classes involved in poisonings reported to CIAV. Given the fact that both these classes currently account for a large proportion of medicines’ consumption in Portugal, morbi-mortality consequences of their possible misuse should be further studied, in order to minimise the associated risks.