The Therapeutic Goods Administration (TGA) is today advising that the supply of the prescription medicine Thelin (sitaxentan) will be suspended in Australia. Pfizer, the company that supplies the medicine, has announced that it will withdraw Thelin from the market globally.
Thelin is a prescription-only medicine used to treat pulmonary hypertension, which is a potentially life-threatening condition. It is estimated that approximately 200 patients are currently taking this medicine in Australia. All the specialist clinical units prescribing Thelin have been contacted by the TGA and advised of this action.
Patients currently taking Thelin should contact their treating doctor as soon as possible to organise the supply of a different medicine. Patients should not cease their use of Thelin until they have been assessed by their treating doctor and switched to another medication. There are several other medicines that may be utilised for the treatment of pulmonary hypertension and the clinical decision for use of a specific medicine should be made by the treating doctor with consideration of the individual patient circumstances.
This action has been taken in response to a review of safety data in clinical trials being undertaken overseas that showed patients were at risk of acute liver failure that in some cases was not reversible. The TGA has received 10 adverse event reports of abnormal liver function in Australian patients receiving Thelin.
Liver toxicity is a well-known side effect of this class of medicines. The Product Information for Thelin in Australia contained a boxed warning of the risk of liver side effects and the use of Thelin was contraindicated in patients with pre-existing liver disease.