Nevertheless,
Replacement solution identified:
For Cynomel’s relay, a new prescription will be necessary.Bartekszewczyk / Istock / Via Getty Images
Résumé
From the end of October 2025, the Sanofi laboratory will make the specialty of Liothyronine available in France in France Thybon 20 Henningto compensate for the Cynomel Marketing Stop 0.025 mg Sarbed tablet provided during this same period. Furthermore,
Thybon 20 Henning presents differences with the French specialty:
- 
. Furthermore,
- The quantity of active ingredient per tablet:Thybon 20 Henning Contains 20 µg of liothyronine hydrochloride per tablet, while cynomel contains 25 µg of sodium liothyronine;
- The composition in excipients: presence of castor oil in the tablet of Thybon 20 Henning ;
- tablets of the tablet: kisenable for Thybon 20 Henning and quadrisable for cynomel;
replacement solution identified
A control of thyroid hormones (TSH, T4 and T3) must be implemented in all patients after the cynomel to the cynomel to Thybon 20 Henning.
To get brought back Thybon 20 Henning, patients will have to present a new prescription. Therefore,
The ANSM alerts on the resemblance between the boxes of Thybon 20 Henning. Consequently, those of L-Thyroxin Henning (levothyroxine) and the risk of confusion between these drugs.
En forecast of the 0.025 mg Sarbed tablet marketing 0.025 mg scheduled for October 31, 2025 (cf. Furthermore, Our article of June 17. For example, 2025), the National Agency for the Safety of Medicines and Health Products (ANSM) authorizes the import of the German specialty Thybon 20 Henning [1] by the Sanofi laboratory.
Importing Thybon 20 Henning In France will start at the time of the cynomel marketing stop. However, that is to say on October 31, replacement solution identified 2025 [2]. The ANSM promises “That there will be no supply of supply between the end of Cynomel distribution. the start of the provision of Thybon”.
In parallel. a marketing authorization (AMM) will be requested for Thybon 20 Henning In France, to allow its long -term marketing on the French market.
A solution for patients under Liothyronine – Replacement solution identified
Cynomel 0.025 mg scored tablet is the only specialty in Liothyronine alone sold in France. There is another specialty, eutyral 100 µg/20 µg scored tablet, which combines leothyronine and levothyroxine.
Cynomel is used in adults and children over 6 years of age to treat hypothyroidies, certain goitters and nodules (cf. Framed).
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The same active ingredient, but differences to take into account – Replacement solution identified
The specialty Thybon 20 Henningidentified as an alternative solution to Cynomel, has a marketing authorization (AMM) in Germany for over 25 years.
Cynomel et Thybon 20 Henning have Liothyronine in common as an active ingredient, but are distinguished by the following elements (summarized in the table below):
- The Liothyronine Salt used;
- the quantity of active ingredient per unit of taking;
- la formulation en excipient ;
- the secular tablet of the tablet;
- Packaging.
replacement solution identified

. Furthermore,
| Cynomel | Thybon 20 Henning | Special recommendations | |
| Presentation | Box of 30 | Box of 50 | |
| International common name (DCI) | Sodium liothyronine | Liothyronine chlorhydrate | |
| Slaughter | Quadrisable tablet | Bisécable tablet with slaughter bar | Use a comprehensive cut-off, without guarantee of perfectly equal cuts |
| Dosage | 25 µg (0.025 mg) of sodium liothyronine equivalent to 24.18 µg of liothyronine base | 20 µg (0.020 mg) from Lothyronine hydrochloride equivalent to 18.94 µg of Liothyronine Base | |
| Excipients | Dihydrate calcium sulfate, gelatin (including phenylalanine), sucrose, wheat starch, stearic acid, talc | Prégelatinized starch (corn), corn starch, microcrystalline cellulose, sodium carbonate, 5 h20 sodium thiosulfate, highly dispersed silicon replacement solution identified dioxide, castor oil hydrogenated | Risk of allergic reaction linked to castor oil |
| Manufacturing site | France | Spain | |
| Expiration | 2 ans | 2 ans |
Biological monitoring recommended after relay by Thybon 20 Henning
In accordance with the French Society of Endocrinology (SFE), the Thyroid Research Group (GRT), and after the opinion of the Professional National Council of Endocrinology Diabetology Nutrition (CNPEDN), and patient associations, patient monitoring in whom Cynomel is replaced by Thybon 20 Henning is based on a TSH, T4 and T3 control :
- systematically 6 to 8 weeks later the start of treatment withThybon ;
- from 6 to 8 weeks After any dose change during treatment;
- In the event of a significant variation in the patient’s weight;
- in front of clinical signs or symptoms evoking a thyroid imbalance, or in the presence of replacement solution identified any other unusual symptoms or felt;
- If clinical signs persist or worsen.

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This close monitoring makes it possible to determine the optimal effective dose taking into account the patient’s feeling, according to the updated recommendations of the HAS in the management of hypothyroidism.
Monitoring the clinical signs and the patient’s feelings should be contextualized with the biological results of the TSH. It is not recommended to use clinical signs as the only parameters.
As a reminder, Liothyronine is contraindicated during pregnancy. Levothyroxine should be used in pregnant women.
Modalities of issuance: a new necessary ordinance
In the event of a cynomel relay by Thybon 20 Henninga new prescription is necessary. Patients concerned should be oriented towards their doctor.
At the pharmacy, the ANSM warns against a risk of confusion between Thybon 20 Henning an l-thyroxin henning (levothyroxine). The packaging of these two specialties marketed replacement solution identified by the Sanofi laboratory are very similar. can be confused in patients taking the two treatments simultaneously.
In order to reduce the risk of drug error. avoid confusion, especially in patients taking these two treatments simultaneously, the ANSM asked the laboratory :
- to affix a label in French on the sachets given to patients by pharmacists;
- to integrate into each sachet of Thybon A letter in French, as well as an information note intended for patients on the precautions for use.
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