Thiocolchicoside-containing medicines

  • Procedure started
  • Under evaluation
  • CHMP opinion
  • European Commission final decision
Current status:
European Commission final decision


European Medicines Agency recommends restricting use of thiocolchicoside by mouth or injection

Medicine only to be used at low doses for additional short-term relief of painful muscle contractures

On 21 November 2013 the European Medicines Agency's Committee on Human Medicinal Products (CHMP) recommended that the authorised uses for thiocolchicoside-containing medicines for use by mouth or injection should be restricted across the European Union (EU). These medicines are now recommended only as an add-on treatment for painful muscle contractures (permanent tightening of the muscle tissue) resulting from spinal conditions in adults and adolescents 16 years of age or older. In addition, the dose of thiocolchicoside by mouth or injection should be restricted.

Thiocolchicoside is a muscle relaxant that has been authorised by national procedures in several EU Member States1 for use by mouth or injection into the muscles in the treatment of painful muscular disorders.

The review of thiocolchicoside was triggered by the Italian medicines regulatory agency, AIFA, following new experimental evidence which suggested that thiocolchicoside was broken down in the body into a metabolite called M2 or SL59.0955 that could damage dividing cells, resulting in aneuploidy (an abnormal number or arrangement of chromosomes). As a result AIFA asked the CHMP to examine the safety profile of this medicine and consider what regulatory action might be appropriate.

The CHMP reviewed the evidence, including the opinions of experts in the field of medicines safety, and concluded that aneuploidy could occur with M2 at levels not much greater than those seen after recommended doses of thiocolchicoside taken by mouth. Aneuploidy is a risk factor for harm to the developing fetus, reduced fertility in men and in theory could increase the risk of developing cancer. The CHMP therefore recommended measures to ensure thiocolchicoside-containing medicines are used as safely as possible. These include restricting the maximum dose and number of days of treatment when given by mouth or injection. Use is also contra-indicated in pregnancy and lactation or in women of childbearing potential not using contraception, as well as in children or for chronic (long-term) conditions. Preparations for local application to the skin, which do not produce substantial levels of M2 in the body, are not affected by this review.

The CHMP opinion was forwarded to the European Commission, which endorsed it and issued a final legally-binding decision, valid across the EU, on 17 January 2014.

1 Czech Republic, France, Greece, Hungary, Italy, Malta, Portugal and Spain.

Key facts

Approved name
Thiocolchicoside-containing medicines
International non-proprietary name (INN) or common name


Associated names
Muscoril and Coltramyl
muscle relaxant
Reference number
Article 31 referrals

This type of referral is triggered when the interest of the Union is involved, following concerns relating to the quality, safety or efficacy of a medicine or a class of medicines.

European Commission final decision
Opinion date
EC decision date

All documents

Document description

  • Questions and answers (Q&A) - easy-to-understand summary of key issues and Committee conclusions
  • Summary of Opinion - contains the CHMP opinion of the referred medicine(s)
  • List of the medicines affected by the referral (Annex I)
  • Scientific conclusions of the Committee (Annex II)

The following two documents are sometimes available:

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