Singulair Mast Cells, Asthma Allergy, Allergy Drugs, Genetic Variability, Acute Asthma
I spent the weekend reading about the development of Singulair. The early studies recognized that the first phase of the acute asthma response bronco-constriction was probably not caused by leukotrienes. They identified histamines and prostaglandins as the probable sources. I don't think that changed because the Singulair literature states that it should not be considered as a treatment for that. Leukotrienes were a source of inflammation caused by eosinophils and mast cells present in greater numbers (than normal) in airway tissue. So, it was beneficial to find a way to decrease that. ... more »
I spent the weekend reading about the development of Singulair. The early studies recognized that the first phase of the acute asthma response bronco-constriction was probably not caused by leukotrienes. They identified histamines and prostaglandins as the probable sources. I don't think that changed because the Singulair literature states that it should not be considered as a treatment for that. Leukotrienes were a source of inflammation caused by eosinophils and mast cells present in greater numbers (than normal) in airway tissue. So, it was beneficial to find a way to decrease that.
The cysLT1 receptor was identified as source of the signals that tell the cells to produce leukotriene. The receptor, a gene, consist of 337 (they think) amino acids. They modified a compound that would bind to that receptor thus blocking the cells ability to produce leukotrienes. This compound is very specific. It was formulated to bind to the "model" receptor. This compound will not even bind to cysLT receptor sub-types. (That is the good thing.) There is an enormous amount of research that discusses the genetic variability of the chemical reactions that occur in the leukotriene (calling it this for simplicity) pathway. We are also seeing that a number of researchers would like to use gene profiles to predict whether patients will respond favorably to different asthma/allergy drugs. ALL PATIENTS HAVE A RIGHT TO KNOW IF IT IS INHERENT THAT SOME PEOPLE WILL NOT RESPOND TO SINGULAIR OR RESPOND ADVERSELY.
There are many studies from the 1998 era that conclude that montelukast is not effective for everyone. Those researchers stated that it can be predicted that those people who are going to respond favorably will do that within the first 14 days or so. That conclusion would be consistent with a genetic component for efficacy and safety of Singulair. Those doctors concluded that those who did not respond within that time frame should not take Singulair for fear of harming them. That makes good sense.
The Italian researchers wanted to know if there was more going on than blocking leukotrienes in the action of montelukast. They set up a "test tube" study regarding montelukast, the cysLT1 receptor, and some t-cells that they selected. Why? Researchers always have something on their minds. They observed the death of these particular t-cells.
Montelukast is a quinoline. We basically know of quinilines and quinolones as compounds that were invented as broad spectrum antibiotics. They work because they interference with bacterial DNA so they cannot replicate themselves. Montelukast is a quinoline modified to bind with the cysLT1 receptor (a gene) and prevent that gene from activating. That's consistent with what a quinoline/quinolone does.
So what does montelukast do in blood plasma if it does not bind to the receptor because of genetic mis-match? (If montelukast does bind, then a chemical reaction has occurred and the liver will break down the by-products. Montelukast metabolized in 10-12 hours.) What happens if it doesn't bind? How long before it breaks down? Does it produce toxic by-products?
I want to know what happens to lymphocytes such as t-cells just because montelukast is a quinoline. Maybe nothing but what's up with the Italians researchers? I want to know if montelukast has the capability to interfere with lymphocytes who can clone themselves. That could be a good thing under circumstances when these lymphocytes are causing inflammation. But it could be a bad thing in the case of normal individuals with no problems.
I want to know if the bad side effects are due to the fact that the body has to break down and metabolize a quinoline that did not bind to the receptor for which it was created. The side effects of Singulair are strangely similar to what is observed in the quinolones such as levaquin. I have not as yet been able to compare montelukast as a quinoline to levaquin as a quinolone. I am hoping to find something on these categories. There may be no reason to worry that they cause similar damage. But frankly, I think that there is. There is some terrible chit happening to some people. The scariest is the neurological damage.
All of these questions would be in the everybody pharma knows to ask category. I don't know where the answers are. I haven't found them as of yet. Maybe there are no answers. We have to remember that Singulair and Vioxx were released in the same year. They have continued to be drugs under the current executive management of Merck. If the Vioxx marketing promoters had their ghost writers, why not the Singulair marketing promoters. The genetic component appears to be widely accepted but we haven't heard one thing about even that.
I think that it is sad that maybe the marketing of Singulair as one stop shopping for asthma/allergies may have destroyed the original concept. I really think from reading the original work that they knew that they couldn't engineer a drug for one size fits all. Everybody gets harmed when information is withheld.
Shame on the allergist who yelled at the mother who wanted to discuss issues. Does he know exactly who is allergic to Singulair and who isn't? Get him a dunce hat. Just because Singulair is marketed for allergies does not mean that you cannot be allergic to it. See the power of Madison Avenue? The ad agencies focus group these drugs to death. The ad agencies cleverly craft the product information. A good piece of legislation would be to prohibit consumer drugs ads.