psychoactive drugs
by Dr Michael J. Leach
flood and fog brains soon before
falls and hip fractures
There is an inherent poetry to pharmacy whereby medicines can help people through intended beneficial effects and harm people through unintended adverse events, including side effects and drug-drug interactions. It is crucial for prescribers to carefully weigh up the risks and benefits of treatment whenever a new medicine is considered for any given patient. As the modern world has an aging population, there have been rises in frailty, multiple morbidities (i.e. multimorbidity), and multiple medicine use. Multiple medicine use can be defined in terms of polypharmacy, which denotes the concurrent use of five or more drugs, and hyper-polypharmacy, which denotes the concurrent use of ten or more drugs. The increasing prevalence of polypharmacy and hyper-polypharmacy means that, in modern society, there is high potential for harmful side effects and drug-drug interactions.
Psychoactive medicines are examples of drugs that have unfavourable side effects and that can interact with one another to cause harm. Psychoactive medicines act on the central nervous system in different ways to elicit therapeutic and adverse effects. The main types of psychoactive medicines are antidepressants, antipsychotics, benzodiazepines, benzodiazepine-related drugs, opioid analgesics, anticholinesterases, antiepileptics, and anti-Parkinson medicines. A common side effect across all these psychoactive medicines is sedation. While treatment with benzodiazepines, benzodiazepine-related drugs, and antipsychotics may be aimed at helping people to relax or sleep at night, the sedative effect can still be harmful when there is unwanted daytime sedation or oversedation. The sedative effects of psychoactive medicines likely explain why these drugs increase the risk of falls and fractures, especially in older, frailer individuals. Furthermore, when any one psychoactive medicine is taken with another psychoactive medicine, there is an increased sedative burden on the patient. This increased sedative burden can place people at an even greater risk of falls and fractures.
Pharmacoepidemiology is the population-level study of medicine use. In original research conducted as part of my PhD in Pharmacoepidemiology, I used a number of study designs and statistical methods to quantify the risk of hip fracture following psychoactive medicine use in older people. I focused on particular types of psychoactive medicines (e.g. antipsychotic drugs and selective serotonin reuptake inhibitor [SSRI] antidepressants) used individually and in combination with one another. The risk of hip fracture was increased for a range of psychoactive medicines, most notably when they were used concurrently. This research is relevant to real world medical practice because the risk factors identified are potentially modifiable. If prescribers better understand the risks associated with psychoactive medicine use, then they can make more informed prescribing decisions and de-prescribe psychoactive medicines where appropriate. Older patients, their carers, and their family members, as well as nursing home staff, would also benefit from better understanding the significant risk posed by the use of psychoactive medicines.
The pharmacoepidemiological studies that make up my PhD thesis have been published in peer-reviewed journals and are available online:
Leach MJ, Pratt NL, Roughead EE. The risk of hip fracture due to mirtazapine exposure when switching antidepressants or using other antidepressants as add-on therapy. Drugs – Real World Outcomes. 2017; 4(4): 247-255. http://dx.doi.org/10.1007/s40801-017-0120-y
Leach MJ, Pratt NL, Roughead EE. The risk of hip fracture in older people using selective serotonin reuptake inhibitors and other psychoactive medicines concurrently: a matched case-control study in Australia. Drugs – Real World Outcomes. 2017; 4(2): 87-96. http://dx.doi.org/10.1007/s40801-017-0107-8
Leach MJ, Pratt NL, Roughead EE. Psychoactive medicine use and the risk of hip fracture in older people: a case-crossover study. Pharmacoepidemiology and Drug Safety. 2015; 24(6): 576-582. https://doi.org/10.1002/pds.3785
Leach MJ, Pratt NL, Roughead EE, Hayward K, Jenkins N. Medicine use among the elderly before and after hip fracture. Australian Journal of Pharmacy. 2014; 95(1125): 72-74. [A secondary publication arranged by the original publisher]. Available here.
Leach MJ, Pratt NL, Roughead EE. Medicine use among older Australians before and after hip fracture. Journal of Pharmacy Practice and Research. 2013; 43(4):265-268. https://doi.org/10.1002/j.2055-2335.2013.tb00271.x
Michael Leach (@m_jleach) is an Australian health researcher, biostatistician, and poet with a PhD in Pharmacoepidemiology and a passion for health humanities. Examples of his science poems are online here: https://imagesofhealth.wordpress.com/.
If you enjoyed this sciku, check out Michael’s other sciku ‘Quality of Life at Seven Years Post-Stroke‘ and ‘The Psychopharmacological Revolution‘, ‘The Core Correlate of Covid-19 Vaccine Acceptance’, ‘The Early Impacts of COVID-19 on Australian General Practice‘, ‘The Burden of Bushfire Smoke‘, and ‘Australian Science Poetry‘ with science communicator Rachel Rayner.