What is Nuedexta - dextromethorphan, quinidine, used for?
Nuedexta is a medicine that contains two active substances, dextromethorphan and quinidine . It is indicated in the treatment of symptoms of pseudobulbar syndrome (PBA) in adults. PBA is a condition in which an injury to some brain areas causes sudden and uncontrollable episodes of crying or laughter, without having been caused by real emotions.
How is Nuedexta - dextromethorphan, quinidine used?
Nuedexta is available as capsules (15 mg or 23 mg dextromethorphan and 9 mg quinidine) and can only be obtained with a prescription. Treatment should be started with the lowest dose (15mg / 9mg) once a day (in the morning) for a week. The dose should then be increased to two capsules per day (in the morning and evening, 12 hours apart). If the patient's response is inadequate after four weeks, the highest dose (23mg / 9mg) can be used twice a day.
How does Nuedexta - dextromethorphan, quinidine work?
Although the exact cause of PBA is unclear, it is believed that it affects the way in which "neurotransmitters" transmit signals between brain cells, chemicals that allow nerve cells to communicate with each other. It is not known how dextromethorphan acts in PBA; it is known for certain that it binds to some receptors of nerve cells in the brain, such as NMDA receptors and sigma-1 receptors for the neurotransmitter glutamate and receptors for the neurotransmitter serotonin. Because these neurotransmitters are involved in the control of emotions, dextromethorphan contributes to the normalization of brain activity, reducing the symptoms of PBA. The role of quinidine is to prevent dextromethorphan from being degraded too early and, therefore, to prolong its action in the body.
What benefit has Nuedexta - dextromethorphan, quinidine shown during the studies?
Nuedexta was examined in one main study involving 326 patients with PBA due to multiple sclerosis or amyotrophic lateral sclerosis. Nuedexta has been compared with placebo (a substance without effects on the body) for 12 weeks. The main measure of effectiveness was the reduction in the number of episodes of laughter or crying. Treatment with Nuedexta was effective in reducing PBA episodes in patients, with a reduction compared to placebo-treated patients that was almost 50% higher. The study also measured the possible variation of patients' symptoms, evaluated with different modalities including the use of a standard scale (called the CNS-LS emotional lability scale, whose score ranges from 7 to 35). A decrease in the total score indicates an improvement in PBA symptoms. After 12 weeks of treatment with Nuedexta, the CNS-LS score decreased by 8.2 points compared to a decrease of 5.7 points for the placebo.
What is the risk associated with Nuedexta - dextromethorphan, quinidine?
The most common side effects with Nuedexta (which may affect up to 1 in 10 people) are diarrhea, nausea, dizziness, headache, drowsiness and fatigue. Reported serious side effects include muscle spasticity (excessive muscle stiffness), respiratory depression (inhibition of breathing) and decreased oxygen saturation in the blood (oxygen levels below normal). For the full list of all side effects reported with Nuedexta, see the package leaflet. Nuedexta should not be used in patients:
- who receive concomitant treatment with quinidine, quinine or mefloquine or who in the past have had some serious problems such as thrombocytopenia (reduction in the number of platelets) due to the use of such medicines;
- with a "prolonged QT interval" (a disorder of the electrical activity of the heart);
- with or at risk of developing complete atrioventricular block (a type of heart rhythm defect);
- with an important history of torsade de pointes, a type of ventricular tachycardia (an abnormal heart rhythm);
- taking thioridazine, a medicine used to treat mental illness;
- who are taking or have taken antidepressant medications called monoamine oxidase inhibitors (MAOIs) in the previous 14 days.
For the full list of limitations, see the package leaflet.
Why has Nuedexta - dextromethorphan, quinidine been approved?
The Agency's Committee for Medicinal Products for Human Use (CHMP) decided that Nuedexta's benefits are greater than its risks and recommended that it be approved for use in the EU. Based on studies conducted on patients with PBA caused by multiple sclerosis and amyotrophic lateral sclerosis, the CHMP concluded that Nuedexta is effective in treating PBA symptoms. The CHMP also noted that there is currently no treatment available for this difficult condition. As for safety, the CHMP has established that dextromethorphan and quinidine have been marketed for several years and that their safety and interactions with other medicines are relatively well known. The main problematic aspects of safety were considered manageable and adequately addressed by the risk reduction measures.
What measures are being taken to ensure the safe and effective use of Nuedexta - dextromethorphan, quinidine?
A risk management plan has been developed to ensure that Nuedexta is used as safely as possible. Based on this plan, safety information has been included in the summary of product characteristics and the package leaflet for Nuedexta, including the appropriate precautions to be followed by healthcare professionals and patients. In addition, the company that makes Nuedexta must ensure that all healthcare professionals who could use Nuedexta receive an information pack and an alert card for patients containing key safety information. The company will also carry out a study on the use of Nuedexta and a study to monitor the safety of Nuedexta, including its effects on the heart and the potential for interaction with other medicines.
More information on Nuedexta - dextromethorphan, quinidine
On 24 June 2013, the European Commission issued a marketing authorization for Nuedexta, valid throughout the European Union. For more information about Nuedexta therapy, read the package leaflet (also part of the EPAR) or contact your doctor or pharmacist. Last update of this summary: 07-2013.
