Information on RxTrends
Data source
This tool uses Primary Care Reimbursement Service (PCRS) data on dispensed medicines prescribed to General Medical Services (GMS) scheme patients, available from the PCRS Reporting and Open Data area. This data reports on medications (which feature in the top 100 agents reported in the data source per month), and therapeutic groups (i.e. drug classes, categorised by the WHO Anatomical Therapeutic Chemical (ATC) second-level code. In addition, monthly data on the number of persons eligible for the GMS scheme are available from the same source.
Citing this tool
If citing this tool in your work, please include the following reference: Hassan Ali A, Moriarty F. RxTrends: An R-based Shiny Application for Visualising Open Data on Prescribed Medications in Ireland. Zenodo; 2025. https://doi.org/10.5281/zenodo.14726890.
Functionality
The tool was developed using RShiny and allows analysis of prescribing of one or more medicine, therapeutic group, or physiological system. These can be searched for by name or ATC code. Each tab includes analysis of a different metric: prescribing frequency, cost, cost per prescribing, prescribing rate per 1,000 GMS eligible persons, and cost rate per 1,000 GMS eligible persons.
- Prescribing frequency is the number of times a medicine was dispensed per month, and corresponds to the variable “Prescribing Frequency” in the source data.
- Cost is the total ingredient costs of dispensing of a medicine in euro and corresponds to the variable “Ingredient Cost” in the source file.
- Cost per prescribing is the mean ingredient cost per dispensing of a medicine, and is derived by dividing the “Ingredient Cost” variable by the “Prescribing Frequency” variable in the source data.
- Prescribing rate and Cost rate are the number of dispensing/ingredient cost of a medicine per 1,000 GMS eligible persons. They are derived by dividing the “Prescribing Frequency” or “Ingredient Cost” variables by the number of GMS eligible persons and multiplying by 1,000.
The compare option can be used when one entity from two different categories are selected (i.e. a medication and a therapeutic group). It derives a ratio of the relevant metric (e.g. the proportion of prescribing in the selected therapeutic group that is the selected medication).
Further considerations
A cyberattack on the health service of the Republic of Ireland in May 2021 caused transmission issues for pharmacy claims for that month, which led to a significant decrease in apparent dispensing for that month and a significant increase for June 2021. To address this anomaly in the data, May and June 2021 were assigned the mean value of the metrics value (e.g. Prescribing, Cost) over these two months. If a record was available for only one month, that value was used exclusively for that month and not applied to the other.
For the top 100 agents, we assigned ATC codes as there were not included in the original source data. Of note, the WHO periodically reclassify medications and alter their assigned ATC code, as described on their website. Where an ATC alteration was introduced, as occurred for pregabalin and gabapentin in 2023, the previous ATC code was assigned to data before the alteration was introduced, and the new ATC code was assigned to data after the alteration was introduced.
The source data provides a more detailed breakdown of medical devices within ATC V07 (e.g. urinary requisites, diagnostic agents, needles) and reports some of these among the top 100 medications and as therapeutic subgroups. To avoid duplication, these V groupings are only included in the tool as therapeutic subgroups.
Eligibility data and application
The monthly figures of the number of GMS eligible persons was not publicly available and were requested directly from the Primary Care Reimbursement Service. More detail on GMS eligibility can be found in Mattsson M, Flood M, Wallace E, Boland F, Moriarty F. Eligibility rates and representativeness of the General Medical Services scheme population in Ireland 2016-2021: A methodological report. HRB Open Res. 2023 Oct 18;5:67. An application to explore this eligibility data has been developed and is available here.
Contact us
If you would like to get in contact, please feel free to get in touch with us at ahmedhassanali@rcsi.ie and frankmoriarty@rcsi.ie.