Last year I went on a 4-month cocktail of vet meds that involved no rest days- 1 week of fenbendazole, then 1 week of prazi/ivermectin in morning and Pyrantel pamoate in the evening. The protocol worked so well against the Morgellons symptoms that I actually was able to catch a common cold after four months (my Morgs typically won't allow such competition). I then felt a severe heart pain that lasted about 20 minutes so I quit the protocol. I blamed it on the pamoate at the time, but don't really know. I also don't know whether the pain was dieoff or a poison reaction.
This chest pain was much scarier than the parasites and even the Morg symptoms, so I just said "Ok let the heart worms live, I submit".