Ethosuximide (Zarontin) 250 mg capsules: Supply issue

Supply issue Active

From 1 August 2022, Essential Ethosuximide was listed to cover an out of stock of Zarontin brand ethosuximide 250 mg capsules.

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Zarontin brand capsules out of stock

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

Once the Zarontin brand is available again in New Zealand, the ‘Essential Ethosuximide’ brand will be delisted

There are 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) will be available so people can keep taking their medicine.

Essential Ethosuximide is 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 has encouraged Clinect to contact Medsafe about getting approval for this brand.

Prescribing and supplying an unapproved medicine

Section 29 of the Medicines Act 1981 allows for medicines that are not Medsafe approved to be prescribed and supplied to people. The medicine must be prescribed by someone registered with the Medical Council of New Zealand – such as, a doctor. 

We know supplying a medicine under section 29 is not ideal. In this case, however, this will allow patients to be able to access an appropriate treatment. 

We apologise for any inconvenience this causes. 

Advice for prescribing under section 29 – BPAC website(external link) 

Prescriber and pharmacist requirements for section 29 medicines – Medsafe website (external link)

Medsafe’s section 29 Declaration / Notification Form [DOC](external link)

What patients need to know about section 29 medicines – Health Navigator website(external link)

The temporary brand looks different but works 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 is this happening?

The supplier of ethosuximide has 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 will be exhausted.
  • 1 January 2023:  The ‘Zarontin’ brand is expected to be available again.  (Pharmacode: 2489937). 
  • Early 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 - Health Navigator(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)