Paliperidone and vomitting

[KuRsAnI]

So, I'm using my anti-psychotic medication to not vomit during my SN intake but I just vomitted coffee this morning... I thought paliperidone was an antiemetic?

 

[autumnal]

So, I'm using my anti-psychotic medication to not vomit during my SN intake but I just vomitted coffee this morning... I thought paliperidone was an antiemetic?

Antiemetics (whether dedicated ones or as a side-effect of the relevant antipsychotics) only ever make you less likely to vomit. They do not completely prevent vomiting.

Additionally, there are different pathways and areas of the brain responsible for vomiting due to different causes. So it's also possible your vomiting may have been caused by fear or anxiety, for example, and thus not covered at all by a particular medication which might only reduce vomiting from drugs/chemicals/toxins.

https://sanctioned-suicide.net/attachments/vomiting-centres-png.12442/

 

[Giraffey]

Echoing what @autumnal says above, it's important to remember that antiemetics don't guarantee to prevent vomiting. For example, one of the components not listed on that particular infographic is the higher cortical areas which feed into the NTS (nucleus tractus solitarius) and essentially have the final approval on whether or not the "go" signal is sent to the CPG (central pattern generator) to initiate the vomiting reflex. The cortical pathway is of course also fed into by the likes of the amygdala which are heavily involved in our instinctive emotional processing and the fear response.

So when you see a big scary lion hurtling towards you, before you have the time to consciously recognise that you're about to be eaten by a lion if you don't run, your amygdala recognises that something very big and loud is coming towards you very fast and reports back to your cortex that there is a threat to evade. Part of that threat response is to make you feel nauseous so as you don't eat anything and your body can conserve energy by not having to digest anything. Broadly speaking, it's that pathway which means that chemotherapy patients who are on their second dose are significantly less likely to vomit after their treatment if they didn't vomit the first time around - and it can be extremely difficult to prevent, even with multiple antiemetics at high doses.

There is even a condition known as functional vomiting syndrome (which is something I treat) whereby patients feel sick and vomit even though there is no physiological reason for them to do so, and even the very strongest antiemetics at the high doses fail to help them. On the other hand, sword swallowers have to tolerate the extreme unpleasantness of having a cold, steel blade in their oesophagus and stomach - causing vomiting much the same was as SN and other irritants do, they must consciously suppress the urge to vomit (don't expect to be able to do that, it takes years of training, many people give up). Vomiting is a complicated subject, you could write a whole book on it, and indeed many people have (myself included).

If you read the mega threads, metoclopramide is generally considered to be the go-to antiemetic for this purpose, namely because it is a D2 dopamine antagonist (see the arrow pointing to 'chemoreceptor trigger zone' on autumnal's graphic) and because it increases gastric motility (your stomach dumps its contents into your intestines quicker -> less stomach irritation). A suitable replacement infrequently mentioned in the guides is domperidone which has similar properties.

Antiemetics such as Ondansetron are less suitable because they have a different mechanism of action. If you read some of the old assisted dying handbooks you'll see antiemetics such as Promethazine, Prochlorperazine or diphenhydramine suggested as suitable for use with SN and other salts. These are antihistamines (H1 antagonists) that block the signals fed to the vomiting centre from the vestibular system (such as the inner ear), they are useful for motion sickness but little use for gastric irritants.

I sometimes see various other novel antiemetics suggested of varying suitability... Olanzapine, Mirtazapine, Risperidone, Lorazepam etc. Discussion of those is best saved for another post, but my general advice would be to stick to the recommended antiemetics, ensure you are of the right mindset (if you are anxious about vomiting and convinced that you will 'throw up', you may find that more likely to happen).

I hope that between these two posts you now have a little more understanding of why you've vomited in spite of the antiemetic effect of Paliperidone. If indeed you do try again, I'd recommend following one of the guides, paying particular attention to the fasting steps and antiemetic regime (it can help to pre-dose a day or two prior if you are particularly sensitive to vomiting).

Either way, may you find peace in life or beyond.