Common side effects when inhaled include stuffy nose, cough, and nausea.[1] Common side effects when placed in the nose or eyes include burning or irritation.[2] Other side effects may include anaphylaxis.[1] While there is no evidence of harm in pregnancy, such use has not been well studied.[3] It is a mast cell stabilizer, which decreases the release of histamine.[1][4]
Cromoglicic acid was made in 1965 and came into medical use in the United States in 1973.[4] It is available as a generic medication.[5] In the United States 120 containers of 5 ml to inhale costs about 130 USD; while 10 ml of eye drops costs about 9 USD as of 2022.[6][5]
In asthma it has been used long-term to prevent worseing in mild-to-moderate disease. Decrease in the frequency and severity of attacks is more likely in extrinsic (atopic) and exercise-induced asthma, especially in younger patients. Therapeutic benefit (when it occurs) develops slowly over 2–4 weeks and lasts 1–2 weeks after discontinuing. However, it is less effective than inhaled steroids and is
seldom used now.
It is given four times daily, but does not provide additive benefit in combination with inhaled corticosteroids.[7]
Allergic rhinitis: Cromoglycate is not a nasal decongestant, but regular 4 times daily use as a nasal spray produces
some symptomatic improvement in many patients after 4–6 weeks. The need for nasal decongestants may be reduced.
Allergic conjunctivitis: Regular use as eye drops is beneficial in some chronic cases.
"Cromolyn works because it prevents the release of mediators that would normally attract inflammatory cells and because it stabilizes the inflammatory cells. MCT mast cells found in the mucosa are stabilised."[8]Nedocromil is another mast cell stabilizer that also works in controlling asthma.
The underlying mechanism of action is not fully understood; for while cromoglicate stabilizes mast cells, this mechanism is probably not why it works in asthma.[9] Pharmaceutical companies have produced 20 related compounds that are equally or more potent at stabilising mast cells and none of them have shown any anti-asthmatic effect.[9] It is more likely that these work by inhibiting the response of sensory C fibers to the irritant capsaicin, inhibiting local axon reflexes involved in asthma, and may inhibit the release of preformed T cell cytokines and mediators involved in asthma. (see review by Garland, 1991)
It is known to somewhat inhibit chloride channels (37% ± 7%)[10] and thus may inhibit the:
exaggerated neuronal reflexes triggered by stimulation of irritant receptors on sensory nerve endings (e.g. exercise-induced asthma)
release of preformed cytokines from several type of inflammatory cells (T cells, eosinophils) in allergen-induced asthma
Note: Another chemical (NPPB: 5-nitro-2(3-phenyl) propylamino-benzoic acid) was shown, in the same study, to be a more effective chloride channel blocker.
Cromolyn sodium was discovered in 1965 by Roger Altounyan who himself had asthma. 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.
as a nasal spray (Rynacrom (UK), Lomusol (France), Nasalcrom (US), Prevalin (non-direct version, NL)) to treat allergic rhinitis.
in a nebulizer solution for aerosol administration to treat asthma.
as an inhaler (Intal, Fisons Pharmaceuticals, UK) for preventive management of asthma.[15] The maker of Intal, King Pharmaceuticals, has discontinued manufacturing the inhaled form, cromolyn sodium inhalation aerosol, due to issues involving CFC-free propellant.[16] As stocks are depleted, this inhaler preparation will no longer be available to patients.[17] In the EU it is manufactured without CFCs by Sanofi, although it must be imported from Canada or Mexico for USA residents.
↑Penumutchu, Srinivasa R.; Chou, Ruey-Hwang; Yu, Chin (2014-10-17). "Interaction between S100P and the anti-allergy drug cromolyn". Biochemical and Biophysical Research Communications. 454 (3): 404–409. doi:10.1016/j.bbrc.2014.10.048. ISSN1090-2104. PMID25450399.