Insomnia or the disability to sleep for consecutive hours can be a mind terrifying one as it may cause a lot of pressure and stress. There are appropriate medications available in market for varied group of individuals. However the question on using Doxylamine better than niquil really needs a medical help because each of the ingredients work differently over each people. Doxylamine succinate is the sleeping ingredient in Nyquil which is the most powerful sedative for preventing any allergies or acting as sleep aids. They are commonly used to treat cold and flu symptoms that are available in generic market and are inexpensive. As both are antihistamines they are predicted to do the same job with a slight variation indeed.