Hacker News Reader

Comment by amelius | Hacker News Reader

> The experimental pill that Tarsus Pharmaceuticals is testing is a formulation of lotilaner, a drug that paralyzes and kills parasites by interfering with the way that signals are passed between their nerve cells.

Who knows what effect this has on signals between our own nerve cells. Yikes.

View on HN

They target gamma-aminobutyric acid chloride channels (GABACl) that aren't present in mammals. There is a relatively narrow therapeutic index in animals, but generally felt to be safe at approved doses. They're given to millions of animals, so we'd probably know if there was a problem.

Lotilaner is selective for mite GABA receptors. No activity has been found for mammalian receptors even at doses far above the ones in clinical use.

It's easier and more plausible than a rat poison that doesn't hurt people; harder and less plausible than an antibiotic that doesn't hurt people; ultimately the proof is in the pudding.

Personally I would not try this in a long lasting formulation, only something oral that washes out completely in a few hours, unless it had been on the market for quite a long time

People also believed that pesticides like Roundup only affect insects. However, after a few decades it is becoming clearer that there is a link with Parkinson's.

See e.g.: https://parkinsonscare.org.uk/pesticides-and-herbicides/

I've also been suspicious of the long lasting topical antiparasitics for cats - The drugs are targeted to glutamate gated chloride channels which mammals don't have, but, off target binding to excitatory glutamate receptors (AMPA/NMDA) is still possible in theory and likely in practice given the adverse/overdose effect is seizures. I'd like to think seizurey behavior should be obvious, but subacute excitotoxicity is harder to characterize - usually is only mentioned in the context of cognitive damage from chronic subacute seizures.

But on the other hand it's good at keeping the ticks from attaching to my cat so they can all move on to me as I sleep, totally worth it

I think existing anti-tick chemicals works the same way, at least from my amateur understanding. Flumethrin (which is used as anti-tick in the collar we use for our dogs) targets the nervous system of parasites, which I understand to be the same approach as what Tarsus Pharmaceuticals is testing.

We probably know a lot about how it does or does not affect humans. "Just asking questions" from an unscientific perspective is why we have people saying things like "GMOs eat the lining of your stomach!"

Reply on news.ycombinator.com