Impact of the methylphenidate shortage on the dispensing of medicines for Attention Deficit Hyperactivity Disorder in Australia: A nationwide cohort study

Impact of the methylphenidate shortage on the dispensing of medicines for Attention Deficit Hyperactivity Disorder in Australia: A nationwide cohort study | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL This is a preprint and has not been peer reviewed. Data may be preliminary. 18 March 2026 V1 Latest version Share on Impact of the methylphenidate shortage on the dispensing of medicines for Attention Deficit Hyperactivity Disorder in Australia: A nationwide cohort study Authors : George Gadalla , Wern Chai , Lisa Kalisch Ellett , and Jack Janetzki [email protected] Authors Info & Affiliations https://doi.org/10.22541/au.177383916.66530975/v1 183 views 78 downloads Contents Abstract Supplementary Material Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract Purpose: To describe nationwide dispensing patterns of methylphenidate in Australia before and during recent prolonged supply shortages, and to assess the extent to which Section 19A (S19A) overseas substitutes contributed to population-level utilisation during the shortage period. Secondary aims were to compare methylphenidate dispensing with other ADHD medicines, examine changes in dispensing across individual strengths and formulations, and quantify delays between S19A approval and Pharmaceutical Benefits Scheme (PBS) listing. Methods: A population-based cohort study was conducted using publicly available monthly dispensing data from the Pharmaceutical Benefits Scheme (PBS) and Repatriation PBS (January 2020–October 2025). Data were standardised to dispensings and Defined Daily Doses (DDD) per 100,000 population. Methylphenidate shortages were identified using the Therapeutic Goods Administration Medicines Shortages database. S19A approvals, PBS listing dates and lapse dates were obtained from the S19A approvals database to determine delays to subsidised access. Results: Dispensing of ADHD medicines increased substantially from 2020 to 2025. Methylphenidate dispensing increased overall but plateaued from late 2024 onward, coinciding with widespread supply disruptions affecting multiple strengths and formulations. DDD analysis demonstrated abrupt reductions in extended‑release methylphenidate strengths (particularly 36 mg and 54 mg) during shortages, with partial compensatory increases in other strengths. Fifteen overseas-registered methylphenidate products received S19A approval; however, time to PBS listing ranged from 83–166 days (median 162 days). After PBS listing, S19A products contributed to <1.5% of all methylphenidate dispensings between July–October 2025. Conclusion: Methylphenidate dispensing in Australia became unstable during extensive supply shortages from late 2024, with incomplete substitution across strengths and modest increases in alternative ADHD medicines. Although numerous S19A products were approved, there was minimal uptake of these products at the population level. As ADHD medicine utilisation continues to rise, strengthened national strategies to improve supply chain resilience, transparency and responsiveness are needed. Supplementary Material File (pds-26-0296-file001.docx) Download 214.14 KB Information & Authors Information Version history V1 Version 1 18 March 2026 Copyright This work is licensed under a Non Exclusive No Reuse License. Keywords adhd medicine shortages methylphenidate pharmacoepidemiology section 19a Authors Affiliations George Gadalla Adelaide University View all articles by this author Wern Chai Adelaide University View all articles by this author Lisa Kalisch Ellett Adelaide University View all articles by this author Jack Janetzki [email protected] Adelaide University View all articles by this author Metrics & Citations Metrics Article Usage 183 views 78 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation George Gadalla, Wern Chai, Lisa Kalisch Ellett, et al. Impact of the methylphenidate shortage on the dispensing of medicines for Attention Deficit Hyperactivity Disorder in Australia: A nationwide cohort study. Authorea . 18 March 2026. DOI: https://doi.org/10.22541/au.177383916.66530975/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu . 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