20 Nov Prescription patterns of ranitidine in Canada (Q20-12)
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Prescription patterns of ranitidine in Canada (Q20-12)
Q20-12
Overview
What was the aim of the study?
- This study, conducted by CNODES, examined the patterns of dispensed H2RAs in Canada by describing demographic and clinical characteristics of users and prescribers and by quantifying rates of use and population exposures.
How was the study conducted?
- CNODES conducted a population-based serial cross-sectional design using prescription claims from community pharmacies in Nova Scotia, Ontario, Manitoba, Saskatchewan, Alberta, and British Columbia.
- Demographic and clinical characteristics of users and prescribers were characterized among subjects newly dispensed an H2RA from 2015 to 2019.
- Rates of use and population exposures from 1996 to 2019 were calculated using mean annual dispensation rates and standardized/cumulative defined daily doses (DDDs).
- Results are presented by age ≥ 65 years (6 provinces) and < 65 years (Manitoba, Saskatchewan, British Columbia).
What did the study find?
- Overall number of people dispensed at least one H2RA:
- ≥ 65 years: over 4.6 million; < 65 years: over 22 million
- Ranitidine prescriptions dispensed:
- ≥ 65 years: 2.4 million; < 65 years: 1.7 million
- Other H2RA prescriptions dispensed:
- ≥ 65 years: 0.7 million; < 65 years: 0.6 million
- Analysis of contemporary H2RA users (2015 – 2019)
- Ranitidine accounted for > 90% of H2RAs dispensed (60% – 65% dispensed to women)
- H2RAs were most commonly prescribed by primary care physicians
- Most switches from H2RAs were to a proton pump inhibitor
- Analysis of rates of dispensations (1996 – 2019)
- For both age groups (≥ 65 years and < 65 years), ranitidine was the most commonly used H2RA and the temporal changes in use followed the same patterns for both sexes
- ≥ 65 years: ranitidine use peaked 1996 – 2004 and subsequently declined
- < 65 years: ranitidine use remained stable 1996 - 2019
- Analysis of population exposures to ranitidine (1996 – 2019)
- ≥ 65 years: highest standardized DDDs in Nova Scotia
- < 65 years: highest standardized DDDs in Saskatchewan
- Estimated annual mean of 142 million ranitidine DDDs.
Implications
- The population exposure to ranitidine can also inform a pharmacoepidemiologic study of cancer risk in Canada. CNODES is well positioned to undertake a large study of the risk of ranitidine exposure and cancer.
Key messages
- This large drug utilization review of H2RAs involved over 10 million Canadians in 6 provinces.
- Ranitidine was the most commonly dispensed H2RA.
- Between 1996 and 2019, ranitidine use declined substantially in persons aged ≥ 65 y and remained stable in those < 65 y.
- Even in the most recent period (2015 – 2019), there was still substantial exposure to ranitidine in the population: an estimated mean of 142 million DDDs annually in 6 provinces.
Manuscripts
Levy AR, Stock D, Paterson JM, Tamim H, Chateau D, Quail J, Ronksley PE, Carney G, Reynier P, Targownik L, for the Canadian Network for Observational Drug Effect Studies (CNODES). Prescription ranitidine use and population exposure in 6 Canadian provinces, 1996 to 2019: a serial cross-sectional analysis. CMAJ Open. 2023;11(6):E1033-E1040.