I have been on anti-depressants since the early 90's. I have clinical depression. Once I start a new anti-depressant and its one that works well for me, then I can take it for about 2 years and then I have to switch to a new one because my body gets used to the old one and it stops working well. I have been on, Zoloft, Prozac, Cymbaulta, Pristiq, Effexor and Paxil. After my husband suddenly died, I had a hard time snapping out of my severe depression so my doctor added Zyprexa in addition to taking Effexor and wow that really helped me out of that dark depression hole. I no longer need the Zyprexa, and am doing much better now. If you have fibromyalgia, or chronic pain problems, (for which I have both) an antidepressant is a good idea, because it is hard not to be depressed when you are hurting all the time. It takes anywhere from 2 weeks to 2 months to see if the medication you are trying works. If it doesnt, try another one. Also, if you are less depressed, you will hurt less as well. Oh yes, I tried amitryptiline as well....it put me on my lips, I couldnt take it. Hope this helps. If you have any questions, just ask!
Hugs, Blu