A/Prof. Luke Grzeskowiak1,2,3, Professor Vivienne Moore4, Ms Kelly Hall4, Dr Jenni Ilomaki3, Dr Danielle Schoenaker5, Dr Elizabeth Lovegrove5, Professor Danielle Mazza6, Professor Kirsten Black7, Dr Debra Kennedy8,9, Professor Michael Davies10, Professor Alice Rumbold2,10
1College of Medicine and Public Health, Flinders University, Adelaide, Australia, 2South Australian Health and Medical Research Institute, Adelaide, Australia, 3Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, Parkville, Australia, 4School of Public Health, University of Adelaide, Adelaide, Australia, 5School of Primary Care, Population Sciences and Medical Education, Faculty of Medicine, University of Southampton, Southampton, United Kingdom, 6Department of General Practice, Monash University, Clayton, Australia, 7Faculty of Medicine and Health, University of Sydney, Sydney, Australia, 8Mothersafe, The Royal Hospital for Women, Randwick, Australia, 9The University of New South Wales, Sydney, Australia, 10Adelaide Medical School, University of Adelaide, Adelaide, Australia
Biography:
Dr Luke Grzeskowiak is a clinical pharmacist at Flinders Medical Centre and an Associate Professor in Clinical Pharmacology at Flinders University and South Australian health and Medical Research Institute. His research seeks to optimise the safe and effective use of medications in pregnancy and lactation.
Abstract:
Background: Category X medications, as assigned by the Australian Therapeutics Goods Administration, are only recommended to be used in women of reproductive age who are also using reliable forms of contraception.
Objective: To estimate longitudinal patterns in dispensing of Australian Therapeutic Goods Administration Pregnancy Classification Category X teratogenic medications to females aged 15 to 49 in Australia and examine patterns of concurrent use of hormonal long-acting reversible contraception (LARC) and other hormonal contraception.
Design: Retrospective cohort study; analysis of 10% random sample of national Pharmaceutical Benefits Scheme dispensing data.
Participants, setting: Females aged 15 to 49 years dispensed a Category X medication between 2013 and 2021 in Australia.
Main outcome measures: Number and proportion of females dispensed a Category X medication, stratified by medication class, age group, and year. Number and proportion of females with concurrent hormonal LARC or other hormonal contraception use at the time of dispensing of Category X medication.
Results: The prevalence of Category X medication dispensing increased from 4.63 per 1,000 to 8.70 per 1,000 between 2013 and 2021, mainly attributable to dermatologicals (e.g. isotretinoin) which accounted for 91.1% of prevalent use. At the time of first dispensing of a Category X medication, the proportion with LARC overlap was 13.2%, while any hormonal contraceptive overlap was 22.0%. There was 2 to 5-fold variation in LARC overlap according to Category X medication class, as well as age group and State/Territory at the time of dispensing.
Conclusions: Concurrent use of highly effective hormonal contraception at the time of dispensing of Category X medications appears low in Australia and raises concerns about potential harms from unintended pregnancy. Increasing awareness and uptake of hormonal contraception use in women prescribed Category X medications appears warranted.
Keywords
teratogens, contraception, pharmacoepidemiology