Azotemia (azot, "nitrogen" + -emia, "blood condition") is a medical condition characterized by abnormally high levels of nitrogen-containing compounds (such as urea, creatinine, various body waste compounds, and other nitrogen-rich compounds) in the blood. It is largely related to insufficient or dysfunctional filtering of blood by the kidneys. It can lead to uremia and acute kidney injury (kidney failure) if not controlled. Types
Azotemia has three classifications, depending on its causative origin: prerenal azotemia, renal azotemia, and postrenal azotemia.Measurements of urea and creatinine (Cr) in the blood are used to assess renal function. For historical reasons, the lab test measuring urea is known as "blood urea nitrogen" (BUN). The BUN:Cr ratio is a useful measure in determining the type of azotemia and will be discussed in each section below. A normal BUN:Cr is equal to 15. Prerenal azotemia
Prerenal azotemia is caused by a decrease in blood flow (hypoperfusion) to the kidneys. However, there is no inherent kidney disease. It can occur following hemorrhage, shock, volume depletion, congestive heart failure, adrenal insufficiency, and narrowing of the renal artery among other things.The BUN:Cr in prerenal azotemia is greater than 20. The reason for this lies in the mechanism of filtration of urea and creatinine. Renal Plasma Flow (RPF) is decreased due to hypoperfusion which results in a proportional decrease in GFR. In turn, the decreased flow and pressure to the kidney will be sensed by baroreceptors in the Juxtaglomerular (JG) Cells of the afferent arteriole.
Cromoglicic acid (INN)—also referred to as cromolyn (USAN), cromoglycate (former BAN), or cromoglicate—is traditionally described as a mast cell stabilizer, and is commonly marketed as the sodium salt sodium cromoglicate or cromolyn sodium. This drug prevents the release of inflammatory chemicals such as histamine from mast cells. Cromoglicic acid has been the non-corticosteroid treatment of choice in the treatment of asthma, for which it has largely been replaced by leukotriene receptor antagonists because of their convenience (and perceived safety). Cromoglicic acid requires administration four times daily, and does not provide additive benefit in combination with inhaled corticosteroids. History
Cromolyn sodium was discovered in 1965 by Roger Altounyan, a pharmacologist who had asthma. It is considered a breakthrough drug in management of asthma, as the patients can be freed from steroids in many cases; however, it is mainly effective as a prophylaxis for allergic and exercise-induced asthma, not as a treatment for acute attacks. Altounyan was investigating certain plants and herbs which have bronchodilating properties. One such plant was khella (Ammi visnaga) which had been used as a muscle relaxant since ancient times in Egypt. Altounyan deliberately inhaled derivatives of the active ingredient khellin to determine if they could block his asthma attacks. After several years of trial he isolated an effective and safe asthma-preventing compound called cromolyn sodium. Preparations
Cromoglicic acid is available in multiple forms:

as a nasal spray (Rynacrom (UK), Lomusol (France), Nasalcrom (the only over-the-counter form, US), Prevalin (non-direct version, NL)) to treat allergic rhinitis. in a nebulizer solution for aerosol administration to treat asthma.