You mean side effects from the medication or the worms?
Plenty of side effects from the Mebendazole and Prazi, it really took me down, felt pretty ill for about a week, maybe longer.
Mebendazole is over the counter available in my country, everybody uses it once in a while when they have itchy anus or diarhea. So I bought a course for a few bucks.
I went back to my doc, told her my experience that I found a lot of worms in my stool after Mebendazole and felt so much better and wanted something stronger as a precaution to kill anything left over and asked for Biltricide (Prazi). She didn't make a lot of trouble and wrote a prescription straight away.
She even wrote a letter for me to go to a tropic disease institute but I felt so much better after the Prazi that I couldnt be bothered to go. I will if complaints come back though.
The worms I had were roundworms and pinworms, and I think some schistosomiasis from Indonesia. But I couldn't 100% deny nor confirm that one.
It's important to clean your house thoroughly afterwards, especially your underwear. Keep your bathroom clean and your nails short, try not to open the water tap or the flush button with the same hand you wiped your ass with, stuff like that to prevent re infection.