Discussion Promethazine as an alternative/substitute Anti-Emetic for use with SN?

[paparoach]

Hi all,

We know that all suicide methods of poisoning ingestion should be accompanied by an anti-emetic, with the PPHB recommending Metoclopramide, Domperidone, Prochlorperazine and Stan's Guide additionally recommending Olanzapine, Alizapramide, Chlorpromazine.

As has been pointed out before, these anti-emetics are potentially harder to source as they are Over-The-Counter or Prescription-Only-Medicines, which require lieing to a Dr or Pharmacist that deals with hundreds of people a week and can spot a liar, knows these specialist medicines may well be developing a reputation for niche use, or just potentially cost multiple times the SN from a dodgy offshore website.

The only anti-emetic I have easy ecommerce access to is Promethazine. No need to lie about symptoms, no face to face interactions, no insane costs.

Whilst I have found user KRSU's post here a very good discussion, I don't believe Promethazine is discussed enough as,

• Both Promethazine and the traditionally recommended Prochorperazine are both anti-emetics of the Phenothiazines family, that work by blocking dopamine and serotonin receptors in the brain.
• It's medical uses include sedation, anxiety before surgery, and to treat short-term insomnia.
• A typical dose of 10mg Metoclopramide is often considered roughly equivalent to a 25mg dose of Promethazine
• Ultimately, I don't believe any anti-emetic is going to stop you from vomitting: everyone vomits. Anecdotal. But there is no escpaing the fact your body is going to try eject the poison, whether you're conscious or not.

Apart from people not wanting to deviate from respected sources, what am I missing here about promethazine as a substitute?

Any and all consideration and contribution welcome,
-p

 

[paparoach]

Polite bump

 

[paparoach]

APeacefulPlace has informed 2025 SN Method updated to:

Hello, glad to share my input as I do have access to the most recent PPEH via membership. There are four notable changes,

1. The Use of B Blocker Propranolol has now been advised, specific dose is 400mg, taken 40 mins prior to SN intake.
2. Additional section called " Analogues " explores SN counterparts that are equally effective and more accessible, that is Potassium Nitrite ( KNO2 ), other nitrites that may offer significant end of life potential includes calcium nitrite, barium nitrite and lithium nitrite none of which are subject to specific restriction.
3. Second additional section called " Eye Witness Accounts " confirms more than 40 nitrite deaths, all were reported peaceful.
4. SN downgraded from 7 to 6 in terms of Peacefulness on the RP Table.

The rest of the section remained the same. Hope you find everything you're looking for.

 

[justmakingsure]

Good research! there's a crap ton of research on this site, but it's always unfortunate that there can't be more people that help with methods like this atm, myself included to be honest. hope this thread finds the right people.

 

[paparoach]

Good research! there's a crap ton of research on this site, but it's unfortunate that there aren't more people that can help/are helping with methods like this atm, myself included. hope this thread finds the right people.

Promethazine discussion was once common it seems about 2 years ago(2023-), but today (2025+), it isn't. I won't speculate why, but all I know is we all have different access and supply, and simply, this is what's easiest available to me.

There is no shame in that, I can gather all the ingredients together, but I'm not picking a fight with a pharmacist, they've prohibited me accessing lidocaine spray and codeine hydrid meds before. They're not stupid, and it wasn't even for SS.

I'm willing to substitute Meto for Promethazine, knowing that the former mitigates vomiting and assists in stomach processing, whilst the latter still acts as an AE but adds sedative propertises.

 

[Eudaimonic]

The issue is that promethazine does not have prokinetic effects. Promethazine is evidently a much weaker dopamine antagonist than metoclopramide, domperidone, and prochlorperazine. The main advantage of taking an antiemetic for SN appears to be their prokinetic effects (of which dopamine antagonists that target the CTZ are the most useful) rather than prevention of nausea and vomiting.

 

[paparoach]

The issue is that promethazine does not have prokinetic effects. Promethazine is evidently a much weaker dopamine antagonist than metoclopramide, domperidone, and prochlorperazine. The main advantage of taking an antiemetic for SN appears to be their prokinetic effects (of which dopamine antagonists that target the CTZ are the most useful) rather than prevention of nausea and vomiting.

Yes, the only reason why I'd favour the tradition Metoclorpramide is for the Prokinetic affects, the affect it has on the stomach to process it's contents.

Domperidone, Prochlorperazine, Olanzapine, Alizapramide, or Chlorpromazine I haven't researched in full if they have an equivalent prokinetic affect, or they're just good at not making you vommit.

It's dangerous of me to just recommend Promethazine, I recognise that, but PPH is clear about Metoclorpramide, and I do advocate that any deviation from the Method is simply inducing more time and pain.

I do genuinely believe everyone vomits. For now, I'm happy with Promethazine as substitute if needed, if I can find SN and Benzos now, then I can get Meto later. This is also why one should avoid Opiods with SN: opiods are anti-kinetic, the cause constipation.

Also ASHWiki states that prochlorperazine is potentially too strong of a dopamine blocker!

 

[Eudaimonic]

Yes, the only reason why I'd favour the tradition Metoclorpramide is for the Prokinetic affects, the affect it has on the stomach to process it's contents.

Domperidone, Prochlorperazine, Olanzapine, Alizapramide, or Chlorpromazine I haven't researched in full if they have an equivalent prokinetic affect, or they're just good at not making you vommit.

It's dangerous of me to just recommend Promethazine, I recognise that, but PPH is clear about Metoclorpramide, and I do advocate that any deviation from the Method is simply inducing more time and pain.

I do genuinely believe everyone vomits. For now, I'm happy with Promethazine as substitute if needed, as if I can find SN and Benzos, I can get Meto later.

Both domperidone and prochlorperazine have prokinetic effects. I don't know which if any is stronger. Olanzapine does not appear to have prokinetic effects, which does not surprise me as it does not affect the dopamine receptors in the chemoreceptor trigger zone (CTZ). Chlorpromazine also does not affect the right dopamine receptors. Alizapride on the other hand does have prokinetic effects by blocking dopamine receptors in the CTZ. There are some other antiemetics that have prokinetic effects as well.

 

[paparoach]

So basically, the only reason why Promethazine isn't recommended in either PPH or Stan's Guide is because it isn't a prokinetic that encourages stomach processing.

Literally that's it... not because it's a worse anti-emetic to stop vomitting, just, it doesn't aid in gastric emptying, which ideally we want.

Mystery solved...

 

[AnotherSadDay]

Mystery solved...

Now I wonder if it would be possible to make a combination of both to get the sedative property of Prome and the prokinetic effect of Meto. Maybe 20 mg of Meto and 25mg of Prome instead of the 30mg Meto?