They are very hard to get rid of. It took me a little over a year of constant fighting them to be clear of them and I live in constant fear of getting reinfected. I found that with mine their life cycle was much shorter than they say not 6 to 9 weeks but closer to 3 weeks, I took the rounds of meds then when i knocked the population way down I started to take pyrantel twice a week and fenbendazole once a month for 3 days. Maybe you can try pulsing the medications every couple of days. I also took 9 weeks of tetracycline. Doxycycline is the best option but I couldnt afford it. Tetracycline works too. Take it while you are taking at least two other anti worm meds at the same time. The combo is what kicks their butts. For the kids combine pyrantel and alinia and the doxyxycline. Enemas when you feel them are a great help.