Can you build up a resistance to Anti-emetics?

[SoVerySorry]

So, I've been on Ondansetron for about... about a year or so, and in about 80% of the cases, the ondansetron (orally dissolving tablets) zapped the nausea within minutes. Other times, it took as long as 30-45 minutes.

I have noticed however, that I've been starting to take 8mg instead of the prescribed 4mg. It feels as if 4mg isn't making enough of a difference anymore as it used to. Should I seek out an 8mg prescription? These things already cost $18 (rounded up) at the given 4mg.

Before this, I was on Promethazine for a really, really, really long time. Promethazine helped at first, but eventually slowed down in effectiveness to the point that I was taking upwards of 60mg (I know, idiotic but my anxiety then was pretty powerful) before I felt any anti-emetic effect.
I do miss the calming feeling of promethazine–it seemingly helped with the anxiety more than the nausea, when the nausea wasn't strong.


tldr; Zofran doesn't seem to be working that strong anymore (promethazine experienced same effects). Do they lose effectiveness?

[Felle]

I think so, if you "abuse" them (take them daily as precaution even if not needed). I dont think you should go over what youve been prescribed. Bring it up to your dr. Good luck!

[mamabear93]

If you don't mind me asking what do you take the anti emetic for?
You can definitely build up a tolerance to anti emetics. Especially if you abuse them. Have you tried natural things for nausea? Ginger capsules, ginger tea, ginger gravol?

I know someone who was going through kemo (sorry if the spelling it wrong) she ate some ginger on the days she wasn't well and it helped her through some tough times.

[SoVerySorry]

I've made an appointment with my Gastroenterologist in which I plan to make my personal final push to get my issues solved I'm staying positive, believing that my issue can be solved once and forever if I make enough of an effort this time around.

Uhmm, I forgot what they termed it. Chronic idiopathic nausea. They wanted to identify it as Functional Nausea and Vomiting, but since I'm not actually vomiting (thanks in large part to anti-emetics), they referred to it as idiopathic nausea. IBS-C is likely attributing to it.
I don't take them daily however. When I flare, I do take more than prescribed, but I sometimes am able to go 3+ days without feeling nauseated enough c: I used to take them at every sign of nausea but I'm trying to gain control of it.

I asked for this, but now I'm a little skeptical of the Ondansetron now that I'm seeing (better yet, feeling) a decrease of efficiency lol. I'm nervous of natural supplements because, well... they aren't regulated, and I usually have to consume them, which is the exact opposite of what I'm able to do when nauseated, which in case also attributed to me purchasing the soluble versions. With Ondansetron, I'm usually given an immediate respite.