Terfenadine is an antihistamine formerly used for the treatment of allergic conditions. It was brought to market by Hoechst Marion Roussel (now Sanofi-Aventis) and was marketed under various brand names, including Seldane in the United States, Triludan in the United Kingdom, and Teldane in Australia. It was superseded by fexofenadine in the 1990s due to the risk of a particular type of disruption of the electrical rhythms of the heart (specifically cardiac arrhythmia caused by QT interval prolongation) and has been withdrawn from markets worldwide.
Terfenadine is a prodrug, generally completely metabolized to the active form fexofenadine in the liver by the enzyme Cytochrome P450 3A4
Due to its near complete metabolism by the liver immediately after leaving the gut, terfenadine normally is not measurable in the plasma.
Terfenadine itself, however, is cardiotoxic at higher doses, while its major active metabolite is not. Terfenadine, in addition to its antihistamine effects, also acts as a potassium channel blocker (Kv11.1 encoded by the gene hERG). Since its active metabolite is not a potassium channel blocker, no cardiotoxicity is associated with fexofenadine. Toxicity is possible after years of continued use with no previous problems as a result of an interaction with other medications such as erythromycin, or foods such as grapefruit. The addition of, or dosage change in, these CYP3A4 inhibitors makes it harder for the body to metabolize and remove terfenadine. In larger plasma concentrations, it may lead to toxic effects on the heart's rhythm (e.g. ventricular tachycardia and torsades de pointes).
Everybody knows what allergies are, but what causes them? What drugs do we have available to address them? As we learned in the immunology series, allergies are symptoms of an immune response to a perceived threat. Histamine is a molecule in the body that orchestrates many aspects of this response, and antihistamines are a class of drugs whose purpose it is to neutralize the effects of histamine in the body. Many of these are over-the-counter drugs which should be familiar to us, like Benadryl, Claritin, Zyrtec, and Allegra. How do these drugs work on the molecular level? Let's find out!
Script by Chris Hofmann
Watch the whole Pharmacology playlist: http://bit.ly/ProfDavePharma
General Chemistry Tutorials: http://bit.ly/ProfDaveGenChem
Organic Chemistry Tutorials: http://bit.ly/ProfDave...
published: 02 Feb 2022
Terfenadine is commonly used as a/an:
Terfenadine is commonly used as a/an:
published: 29 Mar 2020
Difference between Terfenadine and Meclizine
#medicalknowledgeonline
What is Terfenadine ?
What is Meclizine ?
What are the Difference between Terfenadine and Meclizine ?
#medicalknowledgeonline
------------------------------------------------------------
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published: 16 May 2024
The mechanism of action of "Terfenadine" (Seldane) is : [JEE Main-2...
The mechanism of action of "Terfenadine" (Seldane) is :
[JEE Main-2020 (September)]
P
(a) Activates the histamine receptor
W)
(b) Helps in the secretion of histamine
(c) Inhibits the secretion of histamine
(d) Inhibits the action of histamine receptor
📲PW App Link - https://bit.ly/YTAI_PWAP
🌐PW Website - https://www.pw.live
published: 13 Feb 2023
Terfenadine is commonly used as a/an (a) tranquilizer (b) antihistamine (c) antimicrobial
What does terfenadine mean?
A spoken definition of terfenadine.
Intro Sound:
Typewriter - Tamskp
Licensed under CC:BA 3.0
Outro Music:
Groove Groove - Kevin MacLeod (incompetech.com)
Licensed under CC:BA 3.0
Intro/Outro Photo:
The best days are not planned - Marcus Hansson
Licensed under CC-BY-2.0
Book Image:
Open Book template PSD - DougitDesign
Licensed under CC:BA 3.0
Text derived from:
http://en.wiktionary.org/wiki/terfenadine
Text to Speech powered by TTS-API.COM
published: 14 Jul 2015
off-target effects of drugs
directory of Chem Help ASAP videos: https://www.chemhelpasap.com/youtube/
We're now going to discuss one of the most well-known cases of off-target effects, and that involves the hERG receptor. Let's look at the story of terfenadine. So terfenadine is an antihistamine, and it was approved in 1985 by the FDA for the treatment of allergy symptoms. Terfenadine acts through initial extensive, first pass metabolism by cytochrome P3A4 to form fexofenadine. So patients taking terfenadine had almost undetectable levels of terfenadine. They immediately metabolized the drug to fexofenadine, and this was the active allergy agent. Well, patients taking terfenadine started having increased deaths, and actually this caused the drug to be withdrawn from the market in 1997. Well, what happened to this sa...
published: 23 Aug 2020
Medical vocabulary: What does Terfenadine mean
What does Terfenadine mean in English?
published: 19 Jan 2016
How Fexofenadine acts in allergy
Fexofenadine is well known as allegra which acts as a selective H1 antagonist and it belongs to second generation antihistamines. This drug chemically belongs to diphenylmethanes.
#allegra
#antihistamine
#rhinitis
published: 14 Sep 2020
Synthetic drug(seldane) Terfenadine work with histamine | 12 | JEE MAIN | CHEMISTRY | JEE MAINS ...
Synthetic drug(seldane) Terfenadine work with histamine
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Everybody knows what allergies are, but what causes them? What drugs do we have available to address them? As we learned in the immunology series, allergies are...
Everybody knows what allergies are, but what causes them? What drugs do we have available to address them? As we learned in the immunology series, allergies are symptoms of an immune response to a perceived threat. Histamine is a molecule in the body that orchestrates many aspects of this response, and antihistamines are a class of drugs whose purpose it is to neutralize the effects of histamine in the body. Many of these are over-the-counter drugs which should be familiar to us, like Benadryl, Claritin, Zyrtec, and Allegra. How do these drugs work on the molecular level? Let's find out!
Script by Chris Hofmann
Watch the whole Pharmacology playlist: http://bit.ly/ProfDavePharma
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Everybody knows what allergies are, but what causes them? What drugs do we have available to address them? As we learned in the immunology series, allergies are symptoms of an immune response to a perceived threat. Histamine is a molecule in the body that orchestrates many aspects of this response, and antihistamines are a class of drugs whose purpose it is to neutralize the effects of histamine in the body. Many of these are over-the-counter drugs which should be familiar to us, like Benadryl, Claritin, Zyrtec, and Allegra. How do these drugs work on the molecular level? Let's find out!
Script by Chris Hofmann
Watch the whole Pharmacology playlist: http://bit.ly/ProfDavePharma
General Chemistry Tutorials: http://bit.ly/ProfDaveGenChem
Organic Chemistry Tutorials: http://bit.ly/ProfDaveOrgChem
Biochemistry Tutorials: http://bit.ly/ProfDaveBiochem
Biology/Genetics Tutorials: http://bit.ly/ProfDaveBio
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Immunology Tutorials: http://bit.ly/ProfDaveImmuno
EMAIL► [email protected]
PATREON► http://patreon.com/ProfessorDaveExplains
Check out "Is This Wi-Fi Organic?", my book on disarming pseudoscience!
Amazon: https://amzn.to/2HtNpVH
Bookshop: https://bit.ly/39cKADM
Barnes and Noble: https://bit.ly/3pUjmrn
Book Depository: http://bit.ly/3aOVDlT
#medicalknowledgeonline
What is Terfenadine ?
What is Meclizine ?
What are the Difference between Terfenadine and Meclizine ?
#medicalknowledgeonlin...
#medicalknowledgeonline
What is Terfenadine ?
What is Meclizine ?
What are the Difference between Terfenadine and Meclizine ?
#medicalknowledgeonline
------------------------------------------------------------
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#medicalknowledgeonline
The mechanism of action of "Terfenadine" (Seldane) is :
[JEE Main-2020 (September)]
P
(a) Activates the histamine receptor
W)
(b) Helps in the secretion of hist...
The mechanism of action of "Terfenadine" (Seldane) is :
[JEE Main-2020 (September)]
P
(a) Activates the histamine receptor
W)
(b) Helps in the secretion of histamine
(c) Inhibits the secretion of histamine
(d) Inhibits the action of histamine receptor
📲PW App Link - https://bit.ly/YTAI_PWAP
🌐PW Website - https://www.pw.live
The mechanism of action of "Terfenadine" (Seldane) is :
[JEE Main-2020 (September)]
P
(a) Activates the histamine receptor
W)
(b) Helps in the secretion of histamine
(c) Inhibits the secretion of histamine
(d) Inhibits the action of histamine receptor
📲PW App Link - https://bit.ly/YTAI_PWAP
🌐PW Website - https://www.pw.live
What does terfenadine mean?
A spoken definition of terfenadine.
Intro Sound:
Typewriter - Tamskp
Licensed under CC:BA 3.0
Outro Music:
Groove Groove -...
What does terfenadine mean?
A spoken definition of terfenadine.
Intro Sound:
Typewriter - Tamskp
Licensed under CC:BA 3.0
Outro Music:
Groove Groove - Kevin MacLeod (incompetech.com)
Licensed under CC:BA 3.0
Intro/Outro Photo:
The best days are not planned - Marcus Hansson
Licensed under CC-BY-2.0
Book Image:
Open Book template PSD - DougitDesign
Licensed under CC:BA 3.0
Text derived from:
http://en.wiktionary.org/wiki/terfenadine
Text to Speech powered by TTS-API.COM
What does terfenadine mean?
A spoken definition of terfenadine.
Intro Sound:
Typewriter - Tamskp
Licensed under CC:BA 3.0
Outro Music:
Groove Groove - Kevin MacLeod (incompetech.com)
Licensed under CC:BA 3.0
Intro/Outro Photo:
The best days are not planned - Marcus Hansson
Licensed under CC-BY-2.0
Book Image:
Open Book template PSD - DougitDesign
Licensed under CC:BA 3.0
Text derived from:
http://en.wiktionary.org/wiki/terfenadine
Text to Speech powered by TTS-API.COM
directory of Chem Help ASAP videos: https://www.chemhelpasap.com/youtube/
We're now going to discuss one of the most well-known cases of off-target effects, an...
directory of Chem Help ASAP videos: https://www.chemhelpasap.com/youtube/
We're now going to discuss one of the most well-known cases of off-target effects, and that involves the hERG receptor. Let's look at the story of terfenadine. So terfenadine is an antihistamine, and it was approved in 1985 by the FDA for the treatment of allergy symptoms. Terfenadine acts through initial extensive, first pass metabolism by cytochrome P3A4 to form fexofenadine. So patients taking terfenadine had almost undetectable levels of terfenadine. They immediately metabolized the drug to fexofenadine, and this was the active allergy agent. Well, patients taking terfenadine started having increased deaths, and actually this caused the drug to be withdrawn from the market in 1997. Well, what happened to this safe and effective drug? The isolated deaths were observed in patients taking terfenadine with drugs that were known to be 3A4 inhibitors. So what happened was, the first-pass effect was being suppressed, and appreciable levels of terfenadine were building up in the bloodstream of these patients. Now unfortunately terfenadine itself is an inhibitor of something called hERG. hERG stands for human ether-a-go-go receptor gene, and the hERG receptor itself is part of a potassium channel found in heart tissue. hERG inhibitors, like terfenadine, cause... they bind to the channel and they cause actually patient death, because of a cardiovascular risk. Interestingly at the time that terfenadine was withdrawn from the market, the maker of terfenadine had already gained approval for fexofenadine as an antihistamine. Fexofenadine has no hERG activity. In part, because of terfenadine, the FDA now requires all potential drugs to be tested for hERG binding, or hERG receptor binding. The story of terfenadine starts with a drug interaction (metabolism inhibition) and ends with an adverse drug reaction through an off-target effect. From a structural standpoint, hERG activity has become associated with highly lipophilic amines. The log P of terfenadine is 7.1. It's an extremely lipophilic compound and even falls outside the recommended boundaries outlined in Lipinski's rules with a cutoff of log P of 5. Furthermore, terfenadine does contain a basic amine. Terfenadine certainly fits the profile of a lipophilic amine. Now look at fexofenadine. The introduction of a carboxylic acid drops the log P of the structure down around to maybe 4. Fexofenadine's carboxylic acid, which is deprotonated at biological pH, introduces much more polarity into the molecule and reduces off-target activity on the hERG receptor.
directory of Chem Help ASAP videos: https://www.chemhelpasap.com/youtube/
We're now going to discuss one of the most well-known cases of off-target effects, and that involves the hERG receptor. Let's look at the story of terfenadine. So terfenadine is an antihistamine, and it was approved in 1985 by the FDA for the treatment of allergy symptoms. Terfenadine acts through initial extensive, first pass metabolism by cytochrome P3A4 to form fexofenadine. So patients taking terfenadine had almost undetectable levels of terfenadine. They immediately metabolized the drug to fexofenadine, and this was the active allergy agent. Well, patients taking terfenadine started having increased deaths, and actually this caused the drug to be withdrawn from the market in 1997. Well, what happened to this safe and effective drug? The isolated deaths were observed in patients taking terfenadine with drugs that were known to be 3A4 inhibitors. So what happened was, the first-pass effect was being suppressed, and appreciable levels of terfenadine were building up in the bloodstream of these patients. Now unfortunately terfenadine itself is an inhibitor of something called hERG. hERG stands for human ether-a-go-go receptor gene, and the hERG receptor itself is part of a potassium channel found in heart tissue. hERG inhibitors, like terfenadine, cause... they bind to the channel and they cause actually patient death, because of a cardiovascular risk. Interestingly at the time that terfenadine was withdrawn from the market, the maker of terfenadine had already gained approval for fexofenadine as an antihistamine. Fexofenadine has no hERG activity. In part, because of terfenadine, the FDA now requires all potential drugs to be tested for hERG binding, or hERG receptor binding. The story of terfenadine starts with a drug interaction (metabolism inhibition) and ends with an adverse drug reaction through an off-target effect. From a structural standpoint, hERG activity has become associated with highly lipophilic amines. The log P of terfenadine is 7.1. It's an extremely lipophilic compound and even falls outside the recommended boundaries outlined in Lipinski's rules with a cutoff of log P of 5. Furthermore, terfenadine does contain a basic amine. Terfenadine certainly fits the profile of a lipophilic amine. Now look at fexofenadine. The introduction of a carboxylic acid drops the log P of the structure down around to maybe 4. Fexofenadine's carboxylic acid, which is deprotonated at biological pH, introduces much more polarity into the molecule and reduces off-target activity on the hERG receptor.
Fexofenadine is well known as allegra which acts as a selective H1 antagonist and it belongs to second generation antihistamines. This drug chemically belongs t...
Fexofenadine is well known as allegra which acts as a selective H1 antagonist and it belongs to second generation antihistamines. This drug chemically belongs to diphenylmethanes.
#allegra
#antihistamine
#rhinitis
Fexofenadine is well known as allegra which acts as a selective H1 antagonist and it belongs to second generation antihistamines. This drug chemically belongs to diphenylmethanes.
#allegra
#antihistamine
#rhinitis
Synthetic drug(seldane) Terfenadine work with histamine
Class: 12
Subject: CHEMISTRY
Chapter: JEE MAIN
Board:IIT JEE
You can ask any doubt from class 6-12, JEE...
Synthetic drug(seldane) Terfenadine work with histamine
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Synthetic drug(seldane) Terfenadine work with histamine
Class: 12
Subject: CHEMISTRY
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Board:IIT JEE
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Everybody knows what allergies are, but what causes them? What drugs do we have available to address them? As we learned in the immunology series, allergies are symptoms of an immune response to a perceived threat. Histamine is a molecule in the body that orchestrates many aspects of this response, and antihistamines are a class of drugs whose purpose it is to neutralize the effects of histamine in the body. Many of these are over-the-counter drugs which should be familiar to us, like Benadryl, Claritin, Zyrtec, and Allegra. How do these drugs work on the molecular level? Let's find out!
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The mechanism of action of "Terfenadine" (Seldane) is :
[JEE Main-2020 (September)]
P
(a) Activates the histamine receptor
W)
(b) Helps in the secretion of histamine
(c) Inhibits the secretion of histamine
(d) Inhibits the action of histamine receptor
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What does terfenadine mean?
A spoken definition of terfenadine.
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We're now going to discuss one of the most well-known cases of off-target effects, and that involves the hERG receptor. Let's look at the story of terfenadine. So terfenadine is an antihistamine, and it was approved in 1985 by the FDA for the treatment of allergy symptoms. Terfenadine acts through initial extensive, first pass metabolism by cytochrome P3A4 to form fexofenadine. So patients taking terfenadine had almost undetectable levels of terfenadine. They immediately metabolized the drug to fexofenadine, and this was the active allergy agent. Well, patients taking terfenadine started having increased deaths, and actually this caused the drug to be withdrawn from the market in 1997. Well, what happened to this safe and effective drug? The isolated deaths were observed in patients taking terfenadine with drugs that were known to be 3A4 inhibitors. So what happened was, the first-pass effect was being suppressed, and appreciable levels of terfenadine were building up in the bloodstream of these patients. Now unfortunately terfenadine itself is an inhibitor of something called hERG. hERG stands for human ether-a-go-go receptor gene, and the hERG receptor itself is part of a potassium channel found in heart tissue. hERG inhibitors, like terfenadine, cause... they bind to the channel and they cause actually patient death, because of a cardiovascular risk. Interestingly at the time that terfenadine was withdrawn from the market, the maker of terfenadine had already gained approval for fexofenadine as an antihistamine. Fexofenadine has no hERG activity. In part, because of terfenadine, the FDA now requires all potential drugs to be tested for hERG binding, or hERG receptor binding. The story of terfenadine starts with a drug interaction (metabolism inhibition) and ends with an adverse drug reaction through an off-target effect. From a structural standpoint, hERG activity has become associated with highly lipophilic amines. The log P of terfenadine is 7.1. It's an extremely lipophilic compound and even falls outside the recommended boundaries outlined in Lipinski's rules with a cutoff of log P of 5. Furthermore, terfenadine does contain a basic amine. Terfenadine certainly fits the profile of a lipophilic amine. Now look at fexofenadine. The introduction of a carboxylic acid drops the log P of the structure down around to maybe 4. Fexofenadine's carboxylic acid, which is deprotonated at biological pH, introduces much more polarity into the molecule and reduces off-target activity on the hERG receptor.
Fexofenadine is well known as allegra which acts as a selective H1 antagonist and it belongs to second generation antihistamines. This drug chemically belongs to diphenylmethanes.
#allegra
#antihistamine
#rhinitis
Synthetic drug(seldane) Terfenadine work with histamine
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Terfenadine is an antihistamine formerly used for the treatment of allergic conditions. It was brought to market by Hoechst Marion Roussel (now Sanofi-Aventis) and was marketed under various brand names, including Seldane in the United States, Triludan in the United Kingdom, and Teldane in Australia. It was superseded by fexofenadine in the 1990s due to the risk of a particular type of disruption of the electrical rhythms of the heart (specifically cardiac arrhythmia caused by QT interval prolongation) and has been withdrawn from markets worldwide.
Terfenadine is a prodrug, generally completely metabolized to the active form fexofenadine in the liver by the enzyme Cytochrome P450 3A4
Due to its near complete metabolism by the liver immediately after leaving the gut, terfenadine normally is not measurable in the plasma.
Terfenadine itself, however, is cardiotoxic at higher doses, while its major active metabolite is not. Terfenadine, in addition to its antihistamine effects, also acts as a potassium channel blocker (Kv11.1 encoded by the gene hERG). Since its active metabolite is not a potassium channel blocker, no cardiotoxicity is associated with fexofenadine. Toxicity is possible after years of continued use with no previous problems as a result of an interaction with other medications such as erythromycin, or foods such as grapefruit. The addition of, or dosage change in, these CYP3A4 inhibitors makes it harder for the body to metabolize and remove terfenadine. In larger plasma concentrations, it may lead to toxic effects on the heart's rhythm (e.g. ventricular tachycardia and torsades de pointes).