CROMOLYN SODIUM NASAL SPRAY

What is cromolyn sodium?

Cromolyn sodium is available as an over-the-counter nasal spray that can be used to prevent or treat seasonal or long-term allergy symptoms such as sneezing, wheezing, a stuffy or runny nose, and itching. It is a mast cell stabilizer that reduces inflammation in your nose. It can be applied as one spray in each nostril 3-4 times daily every 4-6 hours for up to 6 times daily. You can use it before exposure to allergens to prevent allergy symptoms. Cromolyn sodium should not be used to treat asthma, a sinus infection, or cold symptoms.

How can cromolyn sodium help alleviate certain long COVID symptoms?

Cells in our body called mast cells release histamine, a chemical that causes our allergy symptoms. With a COVID infection, mast cells can be overactivated and release excessive amounts of inflammatory mediators like histamine, leading to some of the symptoms of long COVID.¹ Cromolyn sodium reduces the amount of histamine released from mast cells and blocks the release of other chemicals called cytokines that lead to inflammation. This allows it to be effective in decreasing the inflammatory effects of COVID.²

In addition, cromolyn may reduce neuroinflammation and improve cognitive function in long COVID patients. Inhaled cromolyn has been found to affect microglia directly (the brain’s primary immune cells) to reduce cytokine secretion, which may improve cognitive symptoms such as brain fog.²  It is important to note that the nasal formulation of cromolyn may not show the same effects as its oral or inhaled formulations because it has more of a local effect on the nasal passages.

What evidence supports cromolyn sodium’s use for long COVID?

It is unclear whether nasal cromolyn has enough systemic exposure to exhibit these neuro-inflammatory effects. Anecdotally, patients have reported improvement in post-COVID brain fog after using NasalCrom, but there are currently no studies specifically investigating the use of NasalCrom for cognitive symptoms of COVID.³

There is an ongoing Phase I trial of 10 patients studying the effects of adding cromolyn to the standard of care for hospitalized patients with COVID-19 pneumonia. Cromolyn will be given as a nebulized treatment four times a day for four days, followed by the intranasal spray for two weeks to assess its impact on symptom improvement.⁴ 

What should you be aware of when using cromolyn sodium?

Cromolyn can cause a burning or stinging sensation in the nose and sneezing. Less common side effects include headache, hoarseness, and post-nasal drip. Some may also experience an unpleasant aftertaste. If your symptoms do not improve within two weeks or if you are experiencing shortness of breath, wheezing, or chest tightness, you should stop using Cromolyn, as these symptoms may be due to another underlying condition. 

References:

1)      Weinstock LB, Brook JB, Walters AS, Goris A, Afrin LB, Molderings GJ. Mast cell activation symptoms are prevalent in Long-COVID. Int J Infect Dis. 2021 Nov;112:217-226. doi: 10.1016/j.ijid.2021.09.043

2)      Hafezi B, Chan L, Knapp JP, Karimi N, Alizadeh K, Mehrani Y, Bridle BW, Karimi K. Cytokine Storm Syndrome in SARS-CoV-2 Infections: A Functional Role of Mast Cells. Cells. 2021 Jul 12;10(7):1761. doi: 10.3390/cells10071761

3)      Wang YJ, Monteagudo A, Downey MA, Ashton-Rickardt PG, Elmaleh DR. Cromolyn inhibits the secretion of inflammatory cytokines by human microglia (HMC3). Sci Rep. 2021 Apr 13;11(1):8054. doi: 10.1038/s41598-021-85702-8

4)      LongCovidPharmD. NasalCrom for Neuroinflammation? Studies, Surveys, & Supplements. November 23, 2022. Accessed October 31, 2023. https://pharmd.substack.com/p/nasalcrom-for-neuroinflammation

5)      Michelson E. Cromolyn Sodium for Treatment of COVID-19 Pneumonia. ClinicalTrials.gov. February 14, 2023. Accessed October 31, 2023. https://clinicaltrials.gov/study/NCT05077917