A nasal antihistamine stops Long Covid after an acute infection!

Image created by Gemini AI by Troy Roach (August 2025)

This is HUGE if true! Data is impressive in a randomised trial!

TLDR summary:

1. Use the nasal spray daily... especially if you feel run down or like you are getting sick.
2. Definitely use it two times a day during and after an acute infection.

3. It might help with Long Covid and MCAS by reducing histamine, but it is probably not a cure.
4. Azelastine might be a useful alternative to chlorpheniramine. In a quick search, I see many options for Azelastine but strange pricing, but only one oral (not nasal) option for chlorpheniramine.

5. Both of these drugs have been around for decades so they are cheap and there is good safety data on them.

6. I have been using a different class of nasal spray the second half of my LC journey called Avamys (Flonase). These two can be used together and do different things. Flonase reduces inflammation while the studied spray is an antihistamine.

If true, regular use (many infections are asymptomatic!) of a cheap nasal antihistamine could almost eliminate new cases of long COVID (LC). Here is an AI summary of the research I have highlighted the bits that most people will be interested in:

Intranasal chlorpheniramine shows promise in reducing post-acute sequelae of COVID-19 symptoms based on ACCROS studies.

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Background

WHO declared the end of COVID-19 emergency on May 5, 2023, but long-term effects persist. 

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Post-acute sequelae of COVID-19 (PASC) includes various debilitating symptoms. 

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Intranasal chlorpheniramine (iCPM) has shown potential in reducing SARS-CoV-2 viral burden and disease severity. 

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Methods

The study involved 259 participants from ACROSS I and III trials. 

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A 17-question PASC questionnaire assessed symptoms. 

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Statistical analysis was performed using T-test and Pearson chi-square statistics. 

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Findings

iCPM cohort had significantly lower fatigue (0% vs. 21%, p < 0.001) and difficulty concentrating (0% vs. 27%, p < 0.001). 

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Only 1 patient in the iCPM group reported difficulty performing daily activities compared to 48 in the placebo group (p < 0.001). 

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0% of iCPM patients sought medical attention for PASC symptoms versus 68% in the placebo group (p < 0.001).

Discussion

PASC affects 10-63% of COVID-19 patients, with symptoms lasting over two years for some. 

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iCPM may mitigate PASC through various mechanisms, including blocking histamine release and reducing inflammation. 

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Early intervention with iCPM appears crucial for better outcomes. 

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Conclusions

iCPM effectively reduces PASC symptoms, with a strong association between its use and lower symptom prevalence. 

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Future studies should focus on optimal timing for iCPM administration to maximize benefits.

Azelastine vs Chlorpheniramine (iCPM)

Azelastine might be a useful alternative to chlorpheniramine. In a quick search, I see many options for Azelastine, but only one oral (not nasal) option for chlorpheniramine.

Large price variation for Azelastine!? It should be OTC but some places might require a prescription?

 

An oral form of CPM sold online for ten dollars...Note: Oral sprays can't be used in the nose.

An AI summary of research comparing Az vs CPM :

Overview: The document discusses a clinical trial comparing azelastine and chlorpheniramine for treating systemic mastocytosis symptoms. ​

Background

• Mastocytosis is characterised by excessive mast cells in various organs, leading to symptoms like pruritus and abdominal pain. ​
• Treatment aims to control symptoms by stabilising mast cells or blocking histamine effects. ​

Study Design

• A double-blind, randomised, three-period crossover trial had 15 subjects with mastocytosis. ​
• Subjects received azelastine (4 mg or 8 mg) or chlorpheniramine (12 mg) every 12 hours. ​
• Efficacy was assessed through symptom scores, skin tests, and plasma histamine levels. ​

Results

• Azelastine significantly reduced wheal responses to histamine and morphine sulfate compared to chlorpheniramine. ​
• No significant differences in plasma histamine levels between treatments. ​
• Azelastine was superior in relieving pruritus, while chlorpheniramine caused less fatigue. ​

Conclusions

• Azelastine shows promise in treating mastocytosis symptoms, particularly pruritus, but overall efficacy is similar to chlorpheniramine. ​
• Both medications are effective, but chlorpheniramine may be preferred for managing mastocytosis symptoms. 

This might be a piece of the puzzle for Long COVID, but interventions like low-dose nicotine, LDN, low-dose Abilify, etc will be needed. Although this spray might help avoid LC or a worsening of LC from future infections it might not stop other damage to the nervous and cardiovascular systems with acute infections. Therefore, I still suggest using low-dose nicotine to protect the cholinergic system and interventions like OPC (Grape Seed Extract) to help reduce viral load/damage in the circulatory system.

Lastly, general nasal hygiene (not picking your nose 👃) + Nasal breathing instead of mouth breathing + hydration (hydration nasal sprays) are basics that can have long-term benefits.

Thanks for reading!


Troy Roach
linktr.ee/thenicotinetest

Take care of yourself, and if you can... take care of someone else as well!

PS: Some random thoughts for future exploration:

1. "Chlorpheniramine is also a potent bitter taste receptor (T2R) agonist" An overlap with my "bitter receptor blog post on low-dose nicotine and MCAS in the skin?
May this spray be used topically to stop the allergic skin reaction that 10% of low-dose nicotine patch users suffer from?
2. Both 1% and 0.4% doses seem effective. They only used it for 10 days after a positive PCR. It may be more effective if already in use... and possibly stop infections before they start or keep the infection asymptomatic?
3. There are ocular uses of these meds for allergic rhinitis. May the ocular version have some benefit in acute or Long Covid? Maybe trying oral, nasal and ocular (at a low dose) would be of benefit in LC???

4. Possible conflict of interest? Study was funded by Dr Ferrer...But the study design is sound, and the study participants come from a broad range of institutions and countries.