I took 50mg of agomelatine for around a month for delayed sleep phase syndrome. It worked for around three weeks and then stopped, so I ceased use at the end of week four. And then BAM - my sleep goes haywire. My sleeping patterns were then the absolute worst I've ever had in my life for around six weeks. And I'm talking significantly bad - I had to completely change the times I was working, or I wouldn't have been able to work at all. It definitely screwed me for almost two months - significant impact. These sleeping disturbances were also resistant to change (ie. after skipping a night of sleep in an attempt to be able to sleep the following night - I would be exhausted, but come night time, I would not be able to sleep a wink). I tried quite a few things to correct it, but nothing worked at all.
My sleep seems okay now, and appears to have slowly reverted back to almost where it was, but I would proceed with caution if taking this relatively new medication. I still don't feel as though my sleep is as good as it was before agomelatine, and it has been ~6 months since I last took it.
I was also concerned about any interactions there may be re: agomelatine + other drugs. There are a lot of unknowns in this regard.
If you have not done so already, I strongly recommend that you exhaust absolutely all other options re: correcting your sleep before resorting to medication.
Agomelatine - definitely a negative experience for me overall. YMMV.