Several long COVID patients report improvements within days from antihistamines

[Hip]

Several long COVID patients report substantial improvements within days from the first generation antihistamine diphenhydramine (Benadryl) 25 mg before bed. See:

• Benadryl seems to have helped me
• The “best” I feel is when I take diphenhydramine (Benadryl)
• Back to Benadryl cause it’s the only antihistamine that helps me

Other long COVID patients report major improvements from the first generation antihistamine hydroxyzine 25 mg before bed. See:

• Hydroxyzine shown to have antiviral effects (and resolves 90% of my symptoms)
• Hydroxyzine is a life saver but concerned about long term

Reading through antihistamine reports on a Reddit long COVID sub-forum, it seems that long COVID patients' responses to antihistamines are individual, so if experimenting with antihistamines, it might be a good idea to test more than one, to see which works best.



H1 Versus H2 Antihistamines

H1 antihistamines: loratadine, cetirizine, levocetirizine, fexofenadine, diphenhydramine and hydroxyzine.
H2 antihistamines: famotidine, nizatidine, cimetidine and ranitidine (ranitidine was taken off the market).

Note: H1 antihistamines are usually taken for allergies, asthma, urticaria, allergic rhinitis, etc. H2 antihistamines reduce gastric acid secretion, which is the main reason they are prescribed. But H2 antihistamines will not reduce the amount of stomach acid already present in the stomach at the time of taking them.



Drowsiness With First Generation Antihistamines

Note that first generation H1 antihistamines like diphenhydramine, hydroxyzine and cinnarizine cross the blood-brain barrier and cause drowsiness, impaired short-term memory and concentration problems. Thus first generation antihistamines are best taken before bed.

Second and third generation H1 antihistamines like loratadine, cetirizine, fexofenadine and levocetirizine do not easily cross into the brain, and thus do not cause these side effects, so can be taken during the day.



Long COVID Studies on Antihistamines

A study observed that the H1 antihistamine loratadine 10 mg twice daily in combination with the H2 antihistamine famotidine 40 mg once daily led to improvements in 72% of long COVID patients.

In a case report study, famotidine improved LC neuropsychiatric symptoms.



ME/CFS Patient Anecdotes With Antihistamines

• One ME/CFS patient took cimetidine (Tagamet) 200 mg every other day, and was able to go back to work.
• One ME/CFS patient with moderate ME/CFS which appeared after catching dengue virus moved to near remission after starting cinnarizine 12.5 mg twice daily. Cinnarizine is also a calcium channel blocker, and calcium channel blockers like nimodipine have been found effective for ME/CFS.

 

[SWAlexander]

hydroxyzine and cinnarizine cross the blood-brain barrier and cause drowsiness, impaired short-term memory and concentration problems.

cetirizine

For me it is doom if I don´t take it at night (at least half a cetirizine) I have a burning skin reaction. If I do, I'm drowsy at least until 2 pm including concentration difficulty.
I have not found an alternative yet.

 

[BrightCandle]

I have tried Cirtirizine, Fexofenadine and also Benadryl. Alas there isn't an over the counter H2 blocker so I haven't managed to take the full combination. I didn't find much of benefit from just this H1's other than Benadryl which I think does help a little but causes drowsiness. They help with the skin crawling and rashes but nothing else.

 

[Rich D]

I think antihistamines are most useful if you have MCAS, which many of us have. And some work better than others depending on the person. I saw significant (though not huge) improvement with Singulair (Monteleukast) within a week, but no effect from Pepsid or Zyrtec.

 

[godlovesatrier]

Famotidine can help me with fatigue and was extremely important in allowing me to get sleep while I had covid. But it isn't great for the microbiome so I don't take it that often. It does leave me with dizziness fhr following day which lasts about 6 hours. I think from microbiome ph change possibly.

But interesting it helped long covid patients.

I've experienced terrible allergies this year but anti histamines haven't been that effective and I've tried everything now. Not sure why that is.

 

[Emeline]

Thank you @Hip I use this forum for research on treatment ideas all the time and it feel like 4 out of 5 times, you're there with links and studies, which I appreciate hugely. I've put Claritin and Pepcid (brand names of Loratadine and famotidine) on the shopping list to try.

 

[Emeline]

I’m just short of two weeks trying out an antihistamine treatment. I went with 10mg Ioradine 2x daily (8:30am / 8:30pm), 40mg Famotidine 1x daily (8:30am).

I do not have MCAS as far as I’m aware, which I expect would change results significantly.

The biggest change I’ve noticed is that it’s made me more drowsy, which has led me to wonder if the effectiveness of the treatment is because the patients in the experiment a) were healthcare workers and b) had long Covid and therefore plausibly weren’t aware of, or acting on their knowledge of pacing. Thus, taking the antihistamine may have made them more tired and rest more, and thus feel better.

Looking at my biometrics, my resting heart rate has slightly increased, I’ve been less physically active, my heart rate variably has decreased, and my walking heart rate average has become more erratic.

Possibly related, possibly not, I had both diarrhea and constipation my first week, which is unusual for me.

I’m planning on maintaining this experiment for at least 4 weeks, based on the long Covid study which did the same, but will likely go for 6-12 weeks if results look at all positive.

 

[SWAlexander]

antihistamine

I have been taking Cetirizine for over a year now, only at night, about 20 minutes before going to bed. Yes, it makes me drowsy for about 8 hours, but it also keeps the cytokines at bay. Cytokines are the main problem for many symptoms. There are other symptoms related. See https://forums.phoenixrising.me/threads/question-about-petechien.86983/page-4#post-2452720

Cytokine Storm, Mast Cell Activation Syndrome (MCAS), Endothelial Dysfunction and microclots/thrombosis?​

​

 

[SWAlexander]

Now this:

Autopsy findings in cases of fatal COVID-19 vaccine-induced myocarditis ​

https://pubmed.ncbi.nlm.nih.gov/38221509/​

 

[Emeline]

I’m just short of two weeks trying out an antihistamine treatment. I went with 10mg Ioradine 2x daily (8:30am / 8:30pm), 40mg Famotidine 1x daily (8:30am).

A little over a week later, and I made a change that made a massive difference to me. I moved the Famotidine from morning to evening. I also shifted everything 30 minutes later (8:30am to 9am / 8:30pm to 9pm). Since then, my resting heart rate has improved, and my mood and energy have been better.

It's hard to say if they're better than they were before I started the antihistamines, since the first two weeks on them, I didn't feel very good. I would recommend to anyone giving this a try to have them in the evening, if possible, since that seems to have made things better for me.

I also took propranolol a couple nights when my heart was racing, which was part of what triggered moving the Famotidine to the nighttime. Since changing the time I haven't noticed a problem, but I have been trying to go to sleep shortly after taking my meds.

I was traveling this week and doing an unusually large amount of exercise, so my biometrics are pretty useless. I will say that I did over an hour of exercise on Friday, and it's Sunday and I haven't crashed yet, so that seems like a good sign. I have had my usually aches and pains, and my anxiety seems unusually high, but given the traveling it's hard to judge.

 

[SWAlexander]

I started the antihistamines

I have been taking antihistamines (cetirizine at night before bedtime since 2021) were the only way to quiet down the constant cytokine storm attack. Since my colons have also quieted down as well.
https://swaresearch.blogspot.com/2023/08/what-is-cytokine-storm.html

 

[godlovesatrier]

They help massively. Low dose hydrocortisone is also another one that can help if the inflammation isn't really being controlled by antihistamines.

Although I gues it depends how much mast cell activation you have. I never get improvement from H1 and H2 only gives me improvement through calming down stomach inflammation and in turn that seems to shutdown most of my body and joint inflammation at the same time. Works most of the time if I've got stomach linked issues.

 

[SWAlexander]

Works most of the time if I've got stomach linked issues.

Not only do cytokines affect stomach problems, but they also impact the colon. For this reason, I also took probiotics in addition to antihistamines, to support the affected biome to recuperate.
Hydrocortisone is only needed if cortisol is low and ACTH is out of balance.

 

[godlovesatrier]

You're right. My cortisol was definitely a mess post COVID. For about four to five weeks. It seems to be ok now (one week no issues). But only starred working normally with two or three 5mg doses separated by several days.

Famotidine worked great when I had my first COVID infection in 2022. Couldn't sleep without it because the fatigue was so bad. This time my fatigues been very manageable as has my brainfog but I've had PENE which has been way worse.

Anyway I've given off topic

I'm still working on the stomach issues. Lactoferrin has no effect. I'm going to try marshmallow root I think before meals next. Today and yesterday served brainfog from stomach issues.

 

[ilivewithcfs]

Tried a bunch of antihistamines (cetirizine, loratadine, famotidine), never really worked for me. Famotidine helped a bit initially, but made me wired and started to cause insomnia eventually.

 

[SWAlexander]

This time my fatigues been very manageable as has my brainfog but I've had PENE which has been way worse.

You may consider that it takes about 120 days for all red blood cells (RBCs) to renew and 2–4 weeks for white blood cells (WBCs) to renew after treatment. Brain fog will take quite a while because of BBB and the needed clearing of apoptosis.

Your stomach problem could be a part of a shedding a virus in the feces, process.
Meaning: to discharge usually gradually, especially as part of a pathological process.

 

[SWAlexander]

Again Cortisol is in the news.
This time high Cortisol:
Blood Markers Show Neural Consequences of LongCOVID-19

https://twitter.com/i/web/status/1767169323796234445

 

[Alvin2]

I have tried most of these over the years, no ME effect

 

[Emeline]

A little over a week later, and I made a change that made a massive difference to me. I moved the Famotidine from morning to evening. I also shifted everything 30 minutes later (8:30am to 9am / 8:30pm to 9pm). Since then, my resting heart rate has improved, and my mood and energy have been better.

It's hard to say if they're better than they were before I started the antihistamines, since the first two weeks on them, I didn't feel very good. I would recommend to anyone giving this a try to have them in the evening, if possible, since that seems to have made things better for me.

I have now finished my antihistamine experiment and am now weaning off.

Over the 34 days I took the antihistamines at night, I had an average mood of 3 (out of 5, with 3 being neutral).

Over the 15 days I was taking the antihistamines in the morning I had an average mood of 2.73.

Over the 34 days before I started taking antihistamines, my average mood was 3.08.

I don't find that .08 to be significant decrease between no antihistamines and night antihistamines significant, but I do think the 0.35 between no antihistamines and morning antihistamines was notable.

I don't have MCAS, and I'm more than 4 years into CFS, so perhaps others who do have allergy reactions, or are earlier in their journey may find improvement. I've started manual lymph drainage treatment, and have just been prescribed low-dose naltrexone (LDN), so onto other experiments.

 

[Emeline]

I have been taking antihistamines (cetirizine at night before bedtime since 2021) were the only way to quiet down the constant cytokine storm attack. Since my colons have also quieted down as well.
https://swaresearch.blogspot.com/2023/08/what-is-cytokine-storm.html

Thank you for the recommendation! Since I don't have MCAS, and didn't find improvement on the two antihistamines I tried, I'll be trying other treatment areas, but if I don't have success, I'm sure I'll come back ground to try other antihistamines.