Dextromethorphan + Bupropion

Dextromethorphan/bupropion is a combination antidepressant that brings together two long-established drugs in a single extended-release tablet ^[1]. Dextromethorphan, a compound better known as a cough suppressant, acts in the brain as an antagonist of the NMDA type of glutamate receptor and as an agonist of the sigma-1 receptor ^[2]. Bupropion is a norepinephrine and dopamine reuptake inhibitor already used on its own to treat depression ^[3]. The medicine is marketed as Auvelity by Axsome Therapeutics.

The pairing is designed so that the two ingredients complement each other pharmacologically ^[2]. Taken by itself, dextromethorphan is rapidly broken down in the body by the liver enzyme CYP2D6, which keeps its blood levels low; bupropion is a potent inhibitor of that enzyme, so adding it slows the metabolism of dextromethorphan and allows therapeutic concentrations to build up and persist ^[3]. Bupropion thereby serves both as an antidepressant in its own right and as a pharmacokinetic enhancer of dextromethorphan ^[2].

The combination was approved by the United States Food and Drug Administration in 2022 for the treatment of major depressive disorder in adults ^[1]. In the pivotal phase 3 GEMINI trial, patients taking the combination showed significantly greater reductions in depression rating scores than those taking placebo, with benefit emerging within the first week of treatment ^[1]. Reviews have highlighted that its action on the brain's glutamate system sets it apart from conventional monoamine-based antidepressants and may contribute to a relatively rapid onset of effect ^[2].

Dextromethorphan/bupropion is supplied as an oral extended-release tablet. The most commonly reported side effects in trials included dizziness, nausea, headache, drowsiness, and dry mouth, and, unlike some older agents, it was not associated with weight gain or increased sexual dysfunction ^[1]. Because bupropion can lower the seizure threshold, the product is not used in people with seizure disorders or certain eating disorders. It is a prescription-only medicine and is not classified as a controlled substance in the United States.

This is a prescription antidepressant. Common effects are dizziness, nausea, headache, dry mouth, sleepiness, and decreased appetite; unlike many antidepressants it did not cause weight gain or added sexual dysfunction in trials. Because it contains bupropion it lowers the seizure threshold and is avoided in people with seizure disorders, eating disorders, or those withdrawing from alcohol or sedatives. It carries the antidepressant class warning about increased suicidal thoughts in young people. It must never be combined with MAO inhibitors or other strong serotonergic drugs because of serotonin syndrome risk, and blood pressure should be watched. Avoid stacking with other CYP2D6-inhibiting or dextromethorphan-containing products.

Dextromethorphan/bupropion was developed by the American biopharmaceutical company Axsome Therapeutics under the code name AXS-05, pairing two long-established molecules to create a novel antidepressant. The concept drew on the recognition that dextromethorphan, a decades-old cough suppressant, blocks NMDA glutamate receptors and stimulates sigma-1 receptors, actions that place it among the newer, rapidly acting antidepressant mechanisms. Because dextromethorphan is normally broken down quickly by the liver enzyme CYP2D6, Axsome combined it with bupropion, an established antidepressant that inhibits that enzyme and thereby raises and sustains dextromethorphan levels while contributing its own effects.

The combination was tested in a program of controlled trials, including the pivotal GEMINI study, which supported its efficacy in major depressive disorder. On this evidence the United States Food and Drug Administration approved the product in 2022 under the brand name Auvelity, notable as the first oral NMDA-receptor antagonist approved for depression. It is taken as an extended-release tablet and, unlike some other rapid-acting antidepressants, is not a controlled substance.

Dextromethorphan/bupropion has attracted considerable enthusiasm as one of the first genuinely new mechanisms in oral antidepressant therapy in many years. Its appeal lies in the promise of a faster onset of relief than is typical of conventional medicines that act only on serotonin, with clinical studies suggesting meaningful improvement within the first week or two of treatment. Because it works through the glutamate system rather than by simply boosting monoamines, it offers a fresh option for people whose depression has not responded well to standard drugs.

The fact that it is an oral tablet and not a controlled substance makes it far more convenient than clinic-administered rapid-acting alternatives. A balanced perspective notes that it is a relatively new therapy with a side-effect profile that includes dizziness and dry mouth and that requires attention to drug interactions, but its novel approach and rapid action have made it a welcome and closely watched addition to the treatment of depression.