Although not available in the United States, Valdoxan (agomelatine) is the first ever melatonergic antidepressant in that the drug activates specific melatonin receptors (MT-1, MT-2) in the brain. Valdoxan claims to improve sleep disruption without affecting daytime vigilance by exerting specific actions on the regulation of circadian rhythms. The recommended starting dose is 25mg, once daily.
The big Pharma company Novartis owns the rights to market Valdoxan in the United States, but lists the drug as scheduled for submission to the FDA for possible approval no earlier than 2012.
Why? Well, this medication seems to be having difficulty outperforming placebo. And this makes sense because the regulation of circadian rhythms doesn’t necessarily mean that Valdoxan will have antidepressant effects.
Valdoxan promises enhanced norepinephrine and dopamine release, but the drug’s branding plays up its effects on melatonin, raising the question as to who would most likely benefit from its use. Those prone to seasonal affective disorder? Shift workers?
I suspect that Valdoxan will reduce sleep latency, helping people get to sleep faster. It also promises no sexual side effects or weight gain. But these advantages must not be sufficient enough to motivate Novartis to push for swifter FDA approval. Methinks something is amiss here.