If after several nights use silenor 6 mg stops working for sleep maintenance is there any point in trying 2 tablets/ 12 mg?

Go see your doctor: Check out http://www.Drugs.Com/dosage/doxepin.Html for more info. Maximum dose is 6mg/d when used for insomnia while 150-300mg/d is used for depression. Therefore, this is a decision to be made w/your prescribing doctor. There are other options besides this drug. Don't forget sleep hygiene (http://www.Cdc.Gov/sleep/about_sleep/sleep_hygiene.Htm).