Discussion Mirtazapine is an alternative to Ondansetron as an Antiemetic

[Silent Forrest]

Mirtazapine is an alternative antiemetic to Ondansetron, as both of them have high affinity as serotonin 5-HT3​ receptor antagonists

Ondansetron - Wikipedia

en.wikipedia.org

Mirtazapine - Wikipedia

en.wikipedia.org

Found this through research, whilst looking up the pharmacodynamics behind Ondansetron which works as an anti-emetic because, it acts highly specifically and selectively as a serotonin 5-HT3​ receptor antagonist.

Bare in mind, that in pharmacodynamics the lower the Ki, the stronger your ligand (Latin for "to bind") will bind to a receptor

When looking at the Wikipedia article on Mirtazapine, it states that:
"Mirtazapine significantly improves pre-existing symptoms of nausea, vomiting, diarrhoea, and irritable bowel syndrome in affected individuals.[104]​ Mirtazapine may be used as an inexpensive antiemetic alternative to Ondansetron.[36]"​
"It is a potent 5-HT3​ blocker. It may relieve chemotherapy-related and advanced cancer-related nausea."

The article also presents the pharmacodynamics of Mirtazapine through a receptor binding profile table (shown below), that says Mirtazapine posses a 8.1 Ki affinity towards the serotonin 5-HT3​ receptor antagonists, therefore its a good alternative to Ondansetron.

	Ki​ (nM)	Species	Ref
SERT	>10,000	Human	[75]​[76]​
NET	≥4,600	Human	[77]​[75]​
DAT	>10,000	Human	[75]​[76]​
5-HT1A​	3,330–5,010	Human	[8]​[76]​
5-HT1B​	3,534–12,600	Human	[8]​[76]​
5-HT1D​	794–5,010	Human	[8]​[76]​
5-HT1E​	728	Human	[76]​
5-HT1F​	583	Human	[76]​
5-HT2A​	6.3–69	Human	[8]​[76]​
5-HT2B​	200	Human	[8]​
5-HT2C​	8.9–39	Human	[8]​[76]​
5-HT3​	8.1	Human	[78]​
5-HT4L​	>10,000	Human	[76]​
5-HT5A​	670	Human	[76]​
5-HT6​	ND	ND	ND[76]​
5-HT7​	265	Human	[76]​
α1A​	1,815	Human	[76]​
α2A​	20	Human	[76]​
α2B​	88	Human	[76]​
α2C​	18	Human	[76]​
β	>10,000	Human	[76]​
D1​	4,167	Rat
D2​	>5,454	Human	[76]​
D3​	5,723	Human	[76]​
D4​	2,518	Human	[76]​
H1​	0.14–1.6	Human	[79]​[8]​[76]​
H2​	>10,000	Rat	[80]​[79]​
H3​	83,200	Human	[79]​
H4​	>100,000	Human	[79]​
mACh	670	Human	[8]​[77]​
VGSC	6,905	Rat	[76]​
VDCC	>10,000	Rat	[76]​
Values are Ki​ (nM). The smaller the value, the more strongly the drug binds to the site.

 

[Underneath]

I could be wrong, but I believe the antiemetic needed for most methods need to be D2 dopamine antagonists. Neither mirtazapine or ondansetron fill that requirement.

I could be way wrong, but I'd do some research on mechanism of action for these first.

~U

 

[Silent Forrest]

PPeH April 2022 lists ondansetron (5-HT3​ receptor antagonist) and also Metoclopramide (D2 dopamine antagonist) as effective antiemetics for SN.
The book also mentions due to H2 Antagonists being no longer readily available as much, that you can now use Proton Pump Inhibitors (PPIs) i.e. Somac or Nexium. Before hand, I believe in previous editions they advised against using PPI's over H2 Antagonists.
Just remember Stan's Guide comes from Dec 2019 and is getting quite dated now, whilst PPeH comes from April 2022 and is updated quite frequently, and changes according to the availability of drugs and also pharmacological properties.
Both PPeH and Stan's Guide can be found on this site's - Suicide Resource Compilation, and can be compared for their time and availability relevancies.

 

[Underneath]

PPeH April 2022 lists ondansetron (5-HT3​ receptor antagonist) and also Metoclopramide (D2 dopamine antagonist) as effective antiemetics for SN.
The book also mentions due to H2 Antagonists being no longer readily available as much, that you can now use Proton Pump Inhibitors (PPIs) i.e. Somac or Nexium. Before hand, I believe in previous editions they advised against using PPI's over H2 Antagonists.
Just remember Stan's Guide comes from Dec 2019 and is getting quite dated now, whilst PPeH comes from April 2022 and is updated quite frequently, and changes according to the availability of drugs and also pharmacological properties.
Both PPeH and Stan's Guide can be found on this site's - Suicide Resource Compilation, and can be compared for their time and availability relevancies.

Of course, not trying to imply they are wrong or anything like that.

Rather, I'm going on my own experience with serotonin syndrome, but it might be that my body is more susceptible to that than most other people.

I'm not sure what (if any) methods increase serotonin, but if they do and you use a serotonin antagonist antiemetic, it can increase the risk of getting serotonin syndrome. You could argue that getting it increases the fatality element of a method, but it was a pretty horrific experience when I got it.

I guess my words of advice are basically, chose whatever method you want, just make sure you research everything you can about it before you act.
I don't want to 'scare' people away from any methods, I believe it is a very personal decision, however just try and get as much info as you can.

~U

 

[Silent Forrest]

You are indeed right that methods are a very personal decision, and should never be done light heartedly because what another person says.
As someone could experience serotonin syndrome if they are already on serotonin related drugs, such as antidepressants i.e. Zoloft.
Serotonin syndrome.
The same scenario could be also said for taking D2 antagonist antiemetics and getting Extrapyramidal symptoms, such Parkinsonism like side effects, that is if your taking antipsychotics that aren't D2 antagonists, but are antagonists of other Dopamine receptors.
One must decide for themselves if they want to end their life, and in what particular way, if they choose to do so.

 

[Cathy Ames]

PPeH April 2022 lists ondansetron (5-HT3​ receptor antagonist) and also Metoclopramide (D2 dopamine antagonist) as effective antiemetics for SN.
The book also mentions due to H2 Antagonists being no longer readily available as much, that you can now use Proton Pump Inhibitors (PPIs) i.e. Somac or Nexium. Before hand, I believe in previous editions they advised against using PPI's over H2 Antagonists.
Just remember Stan's Guide comes from Dec 2019 and is getting quite dated now, whilst PPeH comes from April 2022 and is updated quite frequently, and changes according to the availability of drugs and also pharmacological properties.
Both PPeH and Stan's Guide can be found on this site's - Suicide Resource Compilation, and can be compared for their time and availability relevancies.

Maybe double-check and make sure that they are not recommending for BOTH to be taken rather than either/or.

 

[Silent Forrest]

it's interesting that you mentioned serotonin syndrome because some symptoms overlap with Extrapyramidal symptoms, such as the tremors.

 

[Cathy Ames]

it's interesting that you mentioned serotonin syndrome because some symptoms overlap with Extrapyramidal symptoms, such as the tremors.

I think both of these drugs can contribute to serotonin syndrome, unfortunately. But maybe it is less likely with meto?

 

[Silent Forrest]

Maybe double-check and make sure that they are not recommending for BOTH to be taken rather than either/or.

MY sincere apologies you are indeed right, that it does indeed says to take BOTH a (D2 Antagonist) i.e. metoclopramide) and serotonin 5-HT3​ receptor antagonist i.e. ondansetron.
That point, however, has brought my attention to the antipsychotic Olanzapine which does have the following properties: D2 Antagonist Ki 3.00–106 and Serotonin 5-HT3​ receptor antagonist Ki 202. Therefore Olanzapine should meet BOTH requirements for D2 Antagonist and Serotonin 5-HT3 ​antagonist.

Olanzapine - Wikipedia

en.wikipedia.org

 

[damaged_soul]

I was actually prescribed Ondansetron for nausea a couple years ago. Can I use it for the SN method or should I try to get a different antiemetic? I use it for the occasional nausea and it works when the nausea is mild, but when it's severe, I still end up throwing up :(

 

[Sniffer]

I have access to Olanzapine and Mirtazapine under prescription. What doses should I use for SN method? Stans 2 day guide?