Flindy is correct. It is easily possible to be just plain allerg...

Flindy is correct. It is easily possible to be just plain allergic to montelukast- Singulair. Where were the other "allergens" that her child was exposed to? It was, at least hopefully, a sterile environment. Montelukast is a quinoline. Drugs often are built around a core molecular called a pharmacophore, the molecule responsible for the drug's important characteristics. There is an enormous amount of literature regarding adverse side effects for other drugs in that category. At the time when Merck was pursuing quinoline as the pharmacophore, other companies were pursing other core molecules. So a quinoline core is not the only choice of drugs. The huge problem is that doctors are not aware that Singulair is not an anti-histamine. They are not warned that the core molecule is a quinoline so they don't know to watch out for allergic reactions especially serious ones. It would be common knowledge that a quinoline radical (in an acid pH) could react with hydrogen peroxide to produce quinilinic acid, a nasty neurotoxin. When I hear of neuro-psychiatric side effects that appear to coincide with times when hypoglycemia could be happening, then maybe there are some genetically pre-disposed people that actually are experiencing times of ketoacidosis. Scientist have known about quinolinic acid since the 1940's. Malaria drugs containing quinoline come with a warning about hypoglycemia and electrolyte imbalance. Which comes first - the chicken or the egg- the reaction to the drug then the hypoglycemia or the hypoglycemia then the reaction? It would be amazingly easy to prove whether quinolinic acid is responsible for these neurological side effects. I am appalled by two things. One is that Merck has such power over the FDA that the FDA fails to even recognize basic pharmacophore characteristics. Merck manages to snow them somehow with just words - leukotriene receptor antagonist. So what is the FDA reaction? Merck should review their clinical data. How about find some people who are suffering from Singulair side effects and do some tests? Then you might actually find out why. If it turns out that anyone at Merck or FDA knew that montelukast carried significant risk of allergic reactions due to it's pharmacophore and they chose not to reveal that in the literature for marketing reasons, those people should be prosecuted. It should not be the job of doctors who prescribe medications to do their own research.