It depends on individual situations. I would recommend trying 5mg (half pill) first to see if it is work for you. If no, try the whole pill (10mg) per night which I think is suitable for most adults. It is better to seek medical expert advice prior to taking, as there may be side effects to other medication.
February 12 2020
I would recommend no more than 2 per night. For reference, I am 176cm and 78kgs. Smaller or bigger people will vary.