Nuedexta® is a combination product containing dextromethorphan and quinidine. The quinidine has been added because it is a CYP450 2D6 inhibitor and markedly increases the serum levels of dextromethorphan (see Related Pages below).
Here is basic information about this medication. Other articles on this website with more advanced information and tips related to this medication are linked to under Related Pages below..
For the treatment of pseudobulbar affect (PBA).
Starting dose: One capsule daily by mouth for 7 days
Maintenance dose: After 7 days, one capsule two times daily.
Dosage forms and strengths
Capsules: Containing dextromethorphan 20 mg/quinidine sulfate 10 mg
Dextromethorphan has multiple effects in the CNS.
1. Blocks N-methyl-D-aspartate (NMDA) receptors
2. Agonist at sigma-1 receptors
3. Inhibits serotonin reuptake
4. Antagonist at voltage-gated calcium channels
5. Inhibits norepinephrine reuptake
6. May block nicotinic acetylcholine receptors, especially those with α3β4 subunits.
Source: Prescribing Information.
1. With an MAOI or within 14 days after stopping an MAOI.
2. Prolonged QT interval, congenital long QT syndrome, history suggestive of torsades de pointes, or heart failure.
3. Complete atrioventricular (AV) block without an implanted pacemaker, or patients at high risk of complete AV block.
4. On a medication that is metabolized by CYP2D6 AND can prolong the QT interval, e.g., thioridazine or pimozide.
Potentially serious side effects
Dizziness/ risk of fall
Other potential side effects
Adverse events that occurred at least twice as often as on placebo are considered here to be “side effects” of the drug. Percentage differences in the incidence of each adverse event on the drug and on placebo are in parentheses.
Peripheral edema (4%)
Cough (3%) — isn’t that surprising?
Urinary tract infection (3%)
Increased gammaglutamyltransferase (GGT; 3%)
Serotonin syndrome can occur if dextromethorphan/ quinidine is used with a serotoninergic antidepressant
Important! Please refer to Prescribing Information (see link below) for a complete discussion of dosage, administration, warnings and precautions, contraindications, etc.
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