Ethosuximide (Zarontin) 250 mg capsules: Supply issue resolved

There was an out of stock affecting Zarontin brand ethosuximide 250 mg capsules, from August 22 to Feb 23. We listed an alternative to cover the out of stock.

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Updated 2 March 2023: Wholesalers orders of Zarontin brand ethosuximide have now been filled.

Zarontin brand capsules out of stock

Zarontin branded capsules (supplied by Clinect) were out of stock from August 2022 until 2 March 2023. Ethosuximide is a medicine used in the treatment of some types of epilepsy, it is most commonly used by children. About 200 patients were affected by this supply issue.   

There were no supply issues with the Zarontin brand of ethosuximide oral liquid. 

Alternative brand listed

From 1 August 2022, a temporary brand, Essential Ethosuximide (Pharmacode: 2641690), was available so people can keep taking their medicine.

Essential Ethosuximide was not Medsafe approved, which means it has to be prescribed and supplied in line with section 29 of the Medicines Act. While not approved in New Zealand, Essential Ethosuximide is approved in the United Kingdom.

Data sheet and Patient information leaflet for Essentials Ethsuximide – link)

Te Pātaka Whaioranga – Pharmac had encouraged Clinect to contact Medsafe about getting approval for this brand. 

The temporary brand looked different but worked the same way

The Essential Ethosuximide packaging and capsules look different. Each capsule has the same amount of active ingredient as Zarontin. It works in the body in the same way. 

Patient hand out [PDF](external link)

The Essentials Ethosuximide is made by the same manufacturer as Zarontin, but at a different site. While the active ingredients are the same, the capsules have additional preservatives compared to Zarontin. 

Reduced number of capsules in a packet

‘Essential Ethosuximide’ brand comes in a 56-capsule packet. The previous ‘Zarontin’ brand came in a 100-capsule packet. 

Patients will still receive the same number of capsules with each dispensing.

Contains 2 pictures of capsules. Zarontin brand capsules are opaque red with P-D 237 printed on them. Essentials brand capsules are rounder and clear with no colour.
Capsules not shown to scale
Zarontin box has Zarontin in bold capital letters, and the Clinect logo. The Essentials packaging has a thick dark pink line bisecting the label. The dose (250 mg) and brand name appear in the same pink. Information about non-active ingredients also appea.
Comparison of ethosuximide packaging

Why did this happen?

The supplier of ethosuximide experienced an issue with a shipment of Zarontin capsules, which was meant to arrive this month. Because of this, Zarontin capsules are not available. The supplier has sourced an alternative brand so that New Zealanders can continue to access ethosuximide capsules. 

Key dates 

  • 1 August 2022 Essential Ethosuximide (Pharmacode: 2641690, pack size 56) listed in the Pharmaceutical Schedule
  • August 2022:  Stock of ‘Zarontin’ brand of ethosuximide exhausted.
  • 1 March 2023:  The ‘Zarontin’ brand available again. (Pharmacode: 2489937). 
  • later in 2023: Essential Ethosuximide will be delisted once Zarontin is available again

Who to contact?

If you or a member of your whānau take this medicine, talk with your doctor, nurse, or pharmacist if you have any concerns. 

You can also get more information from us at  

Useful links

Information for consumers - Healthify(external link)

Ethosuximide NZ Formulary monograph(external link)

Medsafe datasheet for Zarontin brand [PDF](external link)

Medsafe patient information for Zarontin [PDF](external link)

Data sheet and Patient information leaflet for Essential Ethosuximide – link)