mindcancer
Member
- Mar 27, 2021
- 87
After scrolling through a couple of new threads of people asking and suggesting using motion sickness specialized antiemetics and other people claiming that dopamine antagonists are the only type of antiemetics that work with sodium nitrite, I've decided that the subject needed some clearing up.
Myth: You can use motion sickness preventing drugs such as scopolamine or Dramamine to prevent vomiting.
Truth: No, you cannot. Drugs that prevent motion sickness are a type of drug defined as an anticholergenic drug/agent (more specifically, muscarinic antagonists). Like any other type of antagonist, they have the responsibility of blocking (antagonising) a receptor. In this case, an acetylcholine receptor. These receptors are mainly (almost to 100%) found in the vestibular system. That's the system located in the inner ear sensing balance and orientation. Antihistamines (primarily H1) fall under this category as well.
A few of the common vestibular antiemetics;
Scopolamine
Dramamine
Atropine (not primarily used as)
Cyclizine
Myth: You need to use a dopamine blocker against [insert drug here], or else it won't work. This is what Stan said!
Truth: Although dopamine-2 antagonists are the most effective, they aren't necessarily the only type of antiemetic that works. The chemoreceptor trigger zone (CTZ) lies outside the blood-brain barrier which means that it can sense toxins flowing in the bloodstream very easy. When the CTZ reacts to such an abnormality (for example a high concentration of sodium nitrite) it sends chemical messages to the vomiting centre which makes the person vomit. The CTZ communicates to the vomiting centre mainly via dopamine by activating dopamine receptors, with the main receptor being D2. The CTZ also communicates via a serotonin receptor (5-HT3) - this means that 5-HT3 antagonists can be used as an antiemetic. Ondansetron is a 5-HT3 antagoniser, but it doesn't antagonise the dopamine receptor at all. Even if this is the case, ondansetron will work perfectly fine. The serotonin receptors are mainly found in the vagus nerve where it connects to the vomiting centre. Antagonising the serotonin receptor is ideal to prevent visceral emesis (gastrointestinal) but works for the CTZ as well.
A few of the common 'real' antiemetics;
Metoclopramide (D2 & 5-HT3 antagonist)
Domperidone (D2 antagonist)
Ondansetron (5-HT3 antagonist)
Histamine antagonists & antimuscarinic agents: Strictly made for motion sickness caused by the vestibular system.
Dopamine antagonists: D2 antagonists are optimal but aren't the only option.
Serotonin antagonists: Works hand-in-hand with D2 in the CTZ. Metoclopramide is therefore the best option.
I don't want to claim that Stan spread misinformation. People often don't read up on antiemetics, and there isn't really a need to. Saying that using a dopamine antagonist is necessary was a way of simplifying it for most.
Note: Whilst scopolamine might have a slight antiemetic effect when taken transdermally or orally, it should not primarily be used if a safe death is wanted.
Myth: You can use motion sickness preventing drugs such as scopolamine or Dramamine to prevent vomiting.
Truth: No, you cannot. Drugs that prevent motion sickness are a type of drug defined as an anticholergenic drug/agent (more specifically, muscarinic antagonists). Like any other type of antagonist, they have the responsibility of blocking (antagonising) a receptor. In this case, an acetylcholine receptor. These receptors are mainly (almost to 100%) found in the vestibular system. That's the system located in the inner ear sensing balance and orientation. Antihistamines (primarily H1) fall under this category as well.
A few of the common vestibular antiemetics;
Scopolamine
Dramamine
Atropine (not primarily used as)
Cyclizine
Myth: You need to use a dopamine blocker against [insert drug here], or else it won't work. This is what Stan said!
Truth: Although dopamine-2 antagonists are the most effective, they aren't necessarily the only type of antiemetic that works. The chemoreceptor trigger zone (CTZ) lies outside the blood-brain barrier which means that it can sense toxins flowing in the bloodstream very easy. When the CTZ reacts to such an abnormality (for example a high concentration of sodium nitrite) it sends chemical messages to the vomiting centre which makes the person vomit. The CTZ communicates to the vomiting centre mainly via dopamine by activating dopamine receptors, with the main receptor being D2. The CTZ also communicates via a serotonin receptor (5-HT3) - this means that 5-HT3 antagonists can be used as an antiemetic. Ondansetron is a 5-HT3 antagoniser, but it doesn't antagonise the dopamine receptor at all. Even if this is the case, ondansetron will work perfectly fine. The serotonin receptors are mainly found in the vagus nerve where it connects to the vomiting centre. Antagonising the serotonin receptor is ideal to prevent visceral emesis (gastrointestinal) but works for the CTZ as well.
A few of the common 'real' antiemetics;
Metoclopramide (D2 & 5-HT3 antagonist)
Domperidone (D2 antagonist)
Ondansetron (5-HT3 antagonist)
Histamine antagonists & antimuscarinic agents: Strictly made for motion sickness caused by the vestibular system.
Dopamine antagonists: D2 antagonists are optimal but aren't the only option.
Serotonin antagonists: Works hand-in-hand with D2 in the CTZ. Metoclopramide is therefore the best option.
I don't want to claim that Stan spread misinformation. People often don't read up on antiemetics, and there isn't really a need to. Saying that using a dopamine antagonist is necessary was a way of simplifying it for most.
Note: Whilst scopolamine might have a slight antiemetic effect when taken transdermally or orally, it should not primarily be used if a safe death is wanted.
