Hi Barbie, You're lucky that you can take them on an as needed basis. Wish I could, but my doctor made a schedule out for me to follow and I'll be taking them the rest of my life. My grandmother had PA until the day she died at 97. She took Librax too. I tried it, but it didn't work for me. My health problems are so complicated that I have trouble sorting out what is causing what. Thanks for the heads up on the SFS because I always have to take my other meds into consideration before taking something as simple as OTC drugs. Nausea is usually the sign that I'm getting ready to have a panic attack so I know what you mean. What I really hate are the ones that wake me up out of a sound sleep. I am so much better, but I'm still not where I want to be. I've had to accept my limitations, but that only happened four years ago. Good to hear from you. Teresa