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In a letter to healthcare professionals, drugs manufacturer Pfizer is to warn of serious and fatal adverse reactions following inadvertent administration of tranexamic acid instead of local anaesthetics.
The letter, seen by The Pharmaceutical Journal and dated 30 April 2026, says: “Serious, including fatal, adverse reactions have been reported after inadvertent intrathecal administration [of tranexamic acid] due to mix-ups, mostly with injectable local anaesthetics.”
Pfizer said it was sending the letter on behalf of marketing authorisation holders and in agreement with the Medicines and Healthcare products Regulatory Agency (MHRA).
Tranexamic acid is an antifibrinolytic, used in the prevention and treatment of haemorrhages.
“Intrathecal, epidural, intraventricular and intracerebral use of tranexamic acid solution for injection is contraindicated,” the letter added.
“Cases of medication errors have been identified, including cases reported in the EU, where tranexamic acid injection was inadvertently administered intrathecally or epidurally.
“Most of these cases involved mix-ups of vials or ampoules resulting in erroneous administration of tranexamic acid instead of the intended injectable local anaesthetic (e.g. bupivacaine, levobupivacaine, prilocaine).”
It has added that, when administered intrathecally, serious patient harms had been reported, including prolonged hospitalisation and death, while serious adverse reactions that were reported include severe back, gluteal and lower limb pain, myoclonus, generalised seizures and cardiac arrhythmias.
“Extreme caution should be taken when storing, handling and administering IV formulations of tranexamic acid to ensure the correct route of administration. This includes clearly labelling syringes containing tranexamic acid for IV use only and storing tranexamic acid injectables separately from injectable local anaesthetics,” it added.
The European Medicines Agency (EMA) warned of similar mix-ups in October 2025.
A spokesperson for the MHRA commented: “The MHRA recognises the risk of serious adverse events associated with unintentional intrathecal administration of tranexamic acid and supports efforts to raise awareness of this risk to prevent such incidents occurring in UK hospitals.
“This follows international reports in the literature describing medication errors involving intrathecal administration. The cited letter to healthcare professionals on the Electronic Medicines Compendium will be circulated more widely soon to raise awareness of the need for vigilance when IV tranexamic acid is used. This communication is a precautionary measure to ensure awareness of the risk and follows the conclusion of the EMA review in October [2025].”
Claire Shannon, president of the Royal College of Anaesthetists, said: “Our guidance on safe drug management is clear that all local anaesthetic solutions should be stored separately from IV infusion solutions, to reduce the risk of accidental IV or epidural administration.
“Prefilled syringes have also been shown to reduce medication errors, and our Safe Anaesthesia Liaison Group therefore advocates for more drugs to be made available in prefilled syringes, including tranexamic acid.”
