A drug that has been shown to have a strong antagonism for both histamine and serotonin is
- A) Chlorpheniramine (Chlor-Tirmeton).
- B) Tripolidine (Actidil).
- C) Cyproheptadine (Periactin)***
- D) Loratidine (Claritin).
- E) Promethazine (Phenergan).
The correct answer is: C) Cyproheptadine (Periactin).
Here's why:
- Cyproheptadine is a potent antagonist of both histamine H1 receptors and serotonin 5-HT2 receptors. This makes it effective in treating a variety of conditions, including allergic reactions, migraines, nausea, and vomiting.
- Chlorpheniramine, Tripolidine, Loratidine, and Promethazine are all antihistamines, but they have weaker or no significant antagonism for serotonin receptors.
Here's a breakdown of the other options:
A) Chlorpheniramine (Chlor-Tirmeton):
This is a first-generation antihistamine with weak serotonin antagonism.
B) Tripolidine (Actidil):
This is also a first-generation antihistamine with weak serotonin antagonism.
D) Loratidine (Claritin):
This is a second-generation antihistamine with no significant antagonism for serotonin receptors.
E) Promethazine (Phenergan):
This is a first-generation antihistamine with weak serotonin antagonism, but it is primarily used for its sedative and antiemetic effects.
Therefore, considering its strong antagonism for both histamine and serotonin, cyproheptadine (Periactin) is the correct answer.
