Published: 19 June 2023

Safety Information

Monitoring communication

Medsafe emphasises that patients should NOT stop using any medicine or medical device subject to a monitoring communication. If you have any concerns with a medicine or medical device you are using, please contact your healthcare professional. A monitoring communication does not mean that the medicine or medical device causes an adverse event.

Possible risk of seizures with clonidine

Update to original communication 

19 June 2023 

During the monitoring period (28 November 2022 to 28 May 2023), the Centre for Adverse Reactions Monitoring (CARM) received one case report relating to a tonic-clonic seizure following clonidine use. The event occurred in 1996 in an adult taking clonidine for an off-label indication.  

No further action is required at this stage in relation to clonidine and risk of seizures. However, Medsafe is aware of several adverse drug reactions that have occurred in people using clonidine for off-label indications. Medsafe will include an article about clonidine in a future edition of Prescriber Update.  

The benefit-risk balance for clonidine remains positive when used for its approved indications.  

Original communication

28 November 2022
Monitoring closes 28 May 2023

Medsafe is highlighting a possible risk of seizures with clonidine use. The aim is to encourage further reports and increase the information on this potential safety signal.

This potential safety signal was triggered by a report received by the Centre for Adverse Reactions Monitoring (CARM). The report (CARM ID: 142829) describes a 15-year-old male patient who experienced new-onset non-epileptic seizures and somnolence (sleepiness) after starting clonidine.

Products affected
Additional information
Regulator actions
Reporting

Products affected

Product name	Sponsor
Catapres	Clinect NZ Pty Limited
Catapres-TTS	CARSL Consulting
Clonidine (Teva)	Teva Pharma New Zealand Limited
Clonidine Hydrochloride Medsurge	Medicianz Healthcare Limited
Clonidine Transdermal System USP	Viatris Limited

Clonidine belongs to a group of medicines called vasodilators. These medicines widen the blood vessels, which helps the blood to flow more easily. Clonidine is used to treat high blood pressure (hypertension), prevent migraines and similar types of headaches, and to prevent hot flushes that may occur in women during menopause.^1,2

Clonidine is not approved for use in children and adolescents, as severe adverse reactions have been reported when clonidine is used off-label in this population group.^3,4   

Additional information

There are different types of seizures, and each type of seizure can cause a different set of symptoms. This includes iatrogenic seizures which have been associated with several medicines. ⁵

Seizures are not listed as an adverse event in the clonidine data sheets. However, there are some published case reports that describe seizures following clonidine use. The mechanism whereby clonidine may contribute to seizures is unknown.^6–8

Advice on how to take this medicine and known side effects can be found in the consumer medicine information (CMI) and data sheet.

Search for consumer medicine information and data sheets

Regulator actions

Medsafe is placing this safety concern on the Medicines Monitoring () scheme to encourage reporting of seizures (new onset and increased seizure frequency) with clonidine.

Reporting

Consumers and healthcare professionals are encouraged to report suspected adverse reactions to medicines to the Centre for Adverse Reactions Monitoring (CARM).

References

1. Clinect NZ Pty Limited. 2021. Catapres Consumer Medicine Information January 2021. URL: medsafe.govt.nz/Consumers/CMI/c/CatapresTab.pdf (accessed 14 November 2022).
2. Teva Pharma (New Zealand) Limited. 2021. Clonidine (Teva) Consumer Medicine Information 12 October 2021. URLmedsafe.govt.nz/Consumers/CMI/c/ClonidineBNM.pdf (accessed 14 November 2022).
3. Clinect NZ Pty Limited. 2020. Catapres Data Sheet 30 October 2020. URL: medsafe.govt.nz/profs/datasheet/c/Cataprestabinj.pdf (accessed 3 November 2022).
4. Teva Pharma New Zealand Limited. 2021. Clonidine (Teva) New Zealand Data Sheet 12 October 2021. URL: medsafe.govt.nz/profs/Datasheet/c/clonidinebnmtab.pdf (accessed 3 November 2022).
5. Schachter S. 2022. Evaluation and management of the first seizure in adults (Table 6). In: UpToDate 26 October 2022. URL: uptodate.com/contents/evaluation-and-management-of-the-first-seizure-in-adults (accessed 3 November 2022).
6. Feron FJM, Hendriksen JGM, Nicolai J, et al. 2008. New-onset seizures: A possible association with clonidine? Pediatric Neurology 38(2): 147–9. DOI: https://doi.org/10.1016/j.pediatrneurol.2007.09.016 (accessed 2 November 2022).
7. Kirchberger K, Schmitt H, Hummel C, et al. 1998. Clonidine- and methohexital-induced epileptiform discharges detected by magnetoencephalography (MEG) in patients with localization-related epilepsies. Epilepsia 39(10): 1104–12. DOI: https://doi.org/10.1111/j.1528-1157.1998.tb01297.x (accessed 2 November 2022).
8. Schmitt H, Druschky K, Hummel C, et al. 1999. Detection of an epileptic mirror focus after oral application of clonidine. British Journal of Anaesthesia 83(2): 349–51. DOI: 10.1093/bja/83.2.349 (accessed 9 November 2022).