How to stop coughing at night and finally get some sleep?

Depends on cause... Is your cough worse at night because of being in the supine position? If so, your cough could be due to gerd or post nasal drip or even both. Both have different treatments but the treatments for both are very effective. See your doctor so treatment can be initiated and you can get a good night's sleep! good luck!
Treat the reflux. Night time coughing could be due to reflux. Eliminate caffeine, elevate the head of the bed and try otc reflux meds. You should also be evaluated and have someone look down your throat to rule out other causes.
Cough at night. Coghing at night which keeps you up and not able to sleep may be a symptom of underlying medical condition and you need to find out the cause.It may be related to allergy or asthma..The cogh medicine are only good if the cogh is recent and self limiting, but if ir persists then you should see your doctor to find out the cause and get proper treatment.If you are a smoker then you need to stop smokin.