Published: 15 December 2025
Safety Information
Monitoring communication
Atomoxetine and the possible risk of gynaecomastia
- monitoring closes 15 June 2026
12 December 2025
Medsafe is reviewing the risk of gynaecomastia in individuals taking atomoxetine. The aim of this communication is to encourage further reporting to obtain more information on this potential safety concern. Anyone can submit a report.
This potential safety concern was triggered by a report to the pharmacovigilance database. The report (NZ-Medsafe-162947) describes a 36-year-old male patient who developed bilateral gynaecomastia following a dose increase of atomoxetine.
Products affected
More information
Medsafe's actions
Reporting adverse events
Products affected
Table 1 shows the atomoxetine products approved in New Zealand.
Table 1: Approved atomoxetine products| Product name | Sponsor |
|---|---|
| Apo-Atomoxetine | Arrotex Pharmaceuticals (NZ) Limited |
| Atomoxetine (Arrotex) | Arrotex Pharmaceuticals (NZ) Limited |
Atomoxetine is indicated for the treatment of Attention-Deficient/Hyperactivity Disorder (ADHD), as defined by DSM-IV criteria, in children 6 years of age and older, adolescents and adults.
More information
Gynaecomastia is a benign endocrine disorder in males characterised by the proliferation of glandular breast tissue and localised fat deposition, resulting in breast enlargement.1 Hormonal imbalance is the main cause of gynaecomastia, specifically, the oestrogen-to-androgen ratio.1,2 An increase in this ratio can result in gynaecomastia.
Drug-induced gynaecomastia accounts for approximately 10-25% of all reported cases.2 Gynaecomastia is not listed as an adverse drug reaction (ADR) in the atomoxetine data sheets.3,4 However, it is listed as an ADR in the methylphenidate data sheets, another common medicine for the treatment of ADHD.5-9
See the consumer medicine information (CMI) and data sheet for advice on how to take atomoxetine and the known side effects.
Search for consumer medicine information and data sheets
Medsafe's actions
Medsafe is placing this safety concern on the Medicines Monitoring () scheme to encourage reporting of gynaecomastia with atomoxetine.
Reporting adverse events
Please report suspected adverse reactions to medicines to the Centre for Adverse Reactions Monitoring (CARM). Anyone can submit a report to CARM.
References
1. Yang X, Zheng X, Zhang M, et al. 2024. Drug-induced gynecomastia: Data mining and analysis of the FDA Adverse Event Reporting System database. Clinical Epidemiology 16: 617-30. URL: https://doi.org/10.2147/clep.s470959 (accessed 12 November 2025).
2. Medsafe. 2016. Drug-induced gynaecomastia. Prescriber Update 37(3): 37. URL: www.medsafe.govt.nz/profs/PUarticles/September2016/Drug-induced-gynaecomastia.htm (accessed 12 November 2025).
3. Arrotex Pharmaceuticals (NZ) Limited. 2021. Apo-Atomoxetine New Zealand Data Sheet 4 November 2021. URL: www.medsafe.govt.nz/profs/Datasheet/a/apoatomoxetinecap.pdf (accessed 12 November 2025).
4. Arrotex Pharmaceuticals (NZ) Limited. 2023. Atomoxetine New Zealand Data Sheet 26 April 2023. URL: www.medsafe.govt.nz/profs/Datasheet/a/AtomoxetineGPcap.pdf (accessed 12 November 2025).
5. Janssen-Cilag (New Zealand) Ltd. 2024. Concerta New Zealand Data Sheet 3 July 2024. URL: www.medsafe.govt.nz/profs/Datasheet/c/Concertatab.pdf (accessed 12 November 2025).
6. Teva Pharma (New Zealand) Limited. 2024. Methylphenidate Extended Release (Teva) New Zealand Data Sheet 30 August 2024. URL: www.medsafe.govt.nz/profs/Datasheet/m/methylphenidateTevatab.pdf (accessed 12 November 2025).
7. Novartis New Zealand Ltd. 2024. Ritalin and Ritalin LA New Zealand Data Sheet 30 January 2024. URL: www.medsafe.govt.nz/profs/Datasheet/r/RitalintabSRtabLAtab.pdf (accessed 12 November 2025).
8. AFT Pharmaceuticals Ltd. 2023. Rubifen and Rubifen SR New Zealand Data Sheet May 2023. URL: www.medsafe.govt.nz/profs/Datasheet/r/rubifentabsrtab.pdf (accessed 12 November 2025).
9. AFT Pharmaceuticals Ltd. 2024. Rubifen LA capsule New Zealand Data Sheet 22 January 2024 URL: www.medsafe.govt.nz/profs/Datasheet/r/RubifenLACap.pdf (accessed 12 November 2025).
