“Does 5-HT3 receptor antagonists and D2 receptor antagonist prevent the same type of nausea?”
I know that serotonin blocker are optimal in preventing CINV, but can they theoretically be used as any type of D2 antagonist-based antiemetic? Do 5-HT3 antagonists ONLY prevent CINV?
Male | 24 years old
Medications: metoclopramide, ondansetron
2 Answers
I have never heard of this. Please Google.
Nausea is a complex physiologic response, involving more than one pathway. However, in the end, the body largely responds to nerve stimuli from the brain to create the response we call nausea. The medications you have noted classically involve two neurotransmitters.
(a) 5-HT3 receptor antagonists, for example ondansetron, work by way of the SEROTONIN pathway
(b) D2 antagonists, for example metoclopramide, work by way of the DOPAMINE pathway. Therefore, some of these medications like metoclopramide have an effect of increasing motility in the GI tract.
Clinically speaking, 5-HT3 receptor antagonists (especially ondansetron) have become the workhorse for nausea treatment for many etiologies of nausea, not just CINV. This is because of numerous factors related to this drug class, that include, but are not limited to good patient tolerance, low side effect profile, multiple drug formulations, and cost. So, it is very common for practitioners to prescribe this medication class in most cases of nausea (not just CINV) as a starting point, assess response, and most patients respond well to the therapy.
Because of the above, D2 antagonists tend to be prescribed in special cases generally speaking. These include, but are not limited to scenarios where patients fail to respond to the 5-HT3 receptor antagonists, or are added as an adjunct to 5-HT3 receptor antagonists, or practitioners deem the D2 antagonists to be more aligned with the etiology they are trying to manage.
The other thing to realize is medications tend to have more than one action. This is something we also consider when making clinical decisions.
(a) 5-HT3 receptor antagonists, for example ondansetron, work by way of the SEROTONIN pathway
(b) D2 antagonists, for example metoclopramide, work by way of the DOPAMINE pathway. Therefore, some of these medications like metoclopramide have an effect of increasing motility in the GI tract.
Clinically speaking, 5-HT3 receptor antagonists (especially ondansetron) have become the workhorse for nausea treatment for many etiologies of nausea, not just CINV. This is because of numerous factors related to this drug class, that include, but are not limited to good patient tolerance, low side effect profile, multiple drug formulations, and cost. So, it is very common for practitioners to prescribe this medication class in most cases of nausea (not just CINV) as a starting point, assess response, and most patients respond well to the therapy.
Because of the above, D2 antagonists tend to be prescribed in special cases generally speaking. These include, but are not limited to scenarios where patients fail to respond to the 5-HT3 receptor antagonists, or are added as an adjunct to 5-HT3 receptor antagonists, or practitioners deem the D2 antagonists to be more aligned with the etiology they are trying to manage.
The other thing to realize is medications tend to have more than one action. This is something we also consider when making clinical decisions.
