Also, pyrantel (and Ivermectin for that matter) won't help against flukes and tapeworms.
Normally you won't have any symptoms if you have roundworms and are healthy otherwise, unless you've got a ton of them (but that usually means your immune system is weakened). Your allergies might get worse, and sometimes you can get eczema-like rashes.
Often the most dangerous part of the parasite life cycle is when they die. Especially if they die fast and all at once. This is why you should never take drugs that kill flukes and tapeworms, such as praziquantel, at home, because the adverse reactions can be very fast and severe (including anaphylactic shock and liver failure). This is also why with some flukes, such as
Opistorchis flukes, letting them be is sometimes the best strategy unless you have symptoms that need addressing (blocked liver ducts, bad eosinophylia, etc.)
I (try to remember to) take pyrantel at least twice a year, just in case (gardening, pets, handling dead animals are all good reasons to take roundworm drugs regularly). Everybody in the household should take it at once, including pets. Normally nothing happens (and shouldn't). No need to expect massive bundles of roundworms to come out, like it happens when you give pyrantel to a month-old stray puppy.
However, a couple of years ago I took a dose of pyrantel and forgot about it, but a few hours later I spiked a HIGH fever (104F), of the bad kind, with severe chills and blush-white toes, and a bad headache. Took a few hours to figure out what was going on.
Apparenlty
something died from the pyrantel, and as it was dying, it released toxins that caused a rather severe adverse reaction (and I'm relatively young and healthy). My friend, a doctor, uses this case in her lectures in our medical academy, because typically you don't expect such dramatic symptoms from a single dose of over-the-counter anti-roundworm drug.
“……..Harry, I took CARE of it…..”
pretty bird...