Avrupa Komitesi Flupirtine’in sınırlandırılmasını öneriyor (İng)
European Committee Recommends Restricting Flupirtine
Oral medicines and suppositories containing the nonopioid analgesic flupirtine should be restricted to treating acute pain in adults who can’t take other agents, such as nonsteroidal anti-inflammatory drugs (NSAIDs) and weak opioids, according to a new recommendation from the European Medicines Agency’s Pharmacovigilance Risk Assessment Committee (PRAC), and treatment should not exceed 2 weeks.
The PRAC also recommended that patients have their liver function monitored after each full week of treatment and that treatment be stopped if there are signs of liver problems. The committee recommended against the use of flupirtine in patients with pre-existing liver disease, in those taking other drugs that can cause liver problems, and in those who abuse alcohol.
Flupirtine, a selective neuronal-potassium-channel opener, is used to treat conditions such as muscle tension, cancer pain, menstrual cramps, and pain after orthopedic surgery or injuries. Flupirtine-containing medicines have been authorized since the 1980s and are currently available in the following European Union Member States: Bulgaria, Estonia, Germany, Hungary, Italy, Latvia, Lithuania, Poland, Portugal, Romania, and Slovakia.
The PRAC review and recommendations come in the wake of concerns raised by the German medicines regulatory agency, the Federal Institute for Drugs and Medical Devices (BfArM), after reports surfaced of liver problems in patients taking flupirtine. The cases ranged from high levels of liver enzymes in the blood to liver failure, some of which were fatal or resulted in liver transplantations. BfArM was also concerned about the lack of data on the use of the medicine in treating chronic pain.
The PRAC agreed with BfArM that while there were data from studies of flupirtine in treating acute pain, the data on chronic pain were less convincing. The committee noted the lack of sufficient data on the benefits of flupirtine when used for longer than 4 weeks.
The PRAC noted that liver problems appeared to be related to the duration of treatment and that no cases of liver failure or liver transplantation were reported for patients who took the medicine for 2 weeks or less.
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After considering the data on the benefits in acute pain, as well as the data on the occurrence of liver problems, the PRAC concluded that the proposed restrictions and regular liver monitoring were required to ensure that the benefits of flupirtine outweigh their risks.
Flupirtine was introduced as an alternative to opioids and NSAIDs, but studies later determined that it has multiple other actions, including muscle relaxation. As a selective neuronal-potassium-channel opener, the agent opens potassium channels, thereby reducing excessive electrical activity that leads to pain states.
Today, flupirtine is variously available in EU member states as 100-mg immediate-release capsules, 400-mg extended-release tablets, 75-mg and 150-mg suppositories, and a solution for injection (100 mg).
Because the review covers only nationally authorized medicines, the PRAC recommendation will now be forwarded to the Coordination Group for Mutual Recognition and Decentralized Procedures–Human (CMDh), which will adopt a final position. The CMDh, which is a medicines regulatory body representing the European Union Member States, will consider the recommendation at its meeting June 24-26, 2013.