Can I Take Antihistamines While Getting Allergy Shots

On the first day of my allergy shots appointment- I had a massive dilemma, do I take my allergy mediciatons? Can I take antihistamines while getting allergy shots?

This was a huge thing. I didn’t want to show up for the first day and be sent home because I took my Zyrtec or Flonase.

So- Can I Take Antihistamines While Getting Allergy Shots? The answer is: yes! In fact, it’s recommended as it will help you overall have a lower chance of having a severe allergic reaction.

Plus, it will make your reaction to the shot lower. This means less inflammation or soreness in your arm!

Let’s go a little more in-depth about this.

This is the clinic you're probably going to and desperately asking, 'can i take antihistamines while getting allergy shots'? Thankfully, the answer is yes!!
This is the clinic you’re probably going to and desperately asking, ‘can i take antihistamines while getting allergy shots’? Thankfully, the answer is yes!!

Why Can I Take Antihistamines While Getting Allergy Shots? Won’t It Ruin The Shot?

So at first this seemed a little confusing to me.

If you were taking antihistamines, won’t the allergy shot be useless?

Basically, antihistamines work by well, stopping the production of histamines. Histamines are the things that cause the allergic reactions you and I are so fearful of.

So to me, it wouldn’t make sense to take antihistamines with allergy shots. Wouldn’t it make the shot basically ineffective?

Well, actually- no.

Taking Antihistamines Actually Improves The Allergy Shots

Look- I’m going to be honest. I’m not an allergist or anything, I’m just a patient of allergy shots.

So I don’t really know why it works like this. But this study in 2001 called, ‘Premedication with antihistamines may enhance efficacy of specific-allergen immunotherapy’ actually well, as the title states, proved that the antihistamines actually improved allergy shots.

Basically, they took a group of people asking the same question: ‘Can I take antihistamines while getting allergy shots?’ and put them to solve the case.

They started out with 52 patients. After 3 whole years, they reassesed said patients.

Only 45 patients were still receiving the allergy shots for bee venom.

So they took half of the group and gave them the antihistamine terfenadine, and they gave the rest the ‘placebo’ antihistamine. All of this was going on while they were actively receiving allergy shots.

Here’s what they found:

Out of the 45 patients, 41 patients were stung by bees. 17 of these patients were randomly stung by bees (these guys really aren’t lucky, I can’t even remember the last time I was stung).

The other 24 were stung by bees in a hospital ‘challenge’ (what kind of challenge is this…?)

Of these 41 patients, 20 were on the antihistamine and 21 were not on the antihistamine.

Every single person that was on the antihistamine had no reaction to the sting.

Meanwhile, nearly 30% of the group not on the antihistamine reacted to the bee sting!

What Does This Mean?

So at first glance, you might be saying:

Tommy, duh! They’re on an antihistamine- no wonder they’re not going to react to the bee venom. This doesn’t at all prove the allergy shot effectiveness.

And honestly, that’s what I thought at first as well…

But you have to realize that this study is almost speaking in reverse if that makes sense.

It’s showing that one group was on antihistamines the whole time, and the other one wasn’t the whole time. At the end of the day, the people on the antihistamines didn’t have a reaction. Which is expected.. right? Actually- no.

These people are on allergy shots for a reason. If they could just take antihistamines and solve everything, they probably wouldn’t be on allergy shots in the first place.

This means that when they are now combining the antihistamine and allergy shots, it is proving a near 100% efficiency rate against bee stings.

No longer are the days where the patient has to go to the clinic to get checked out- they are essentially cured on this antihistamine now.

Furthermore, it proves that when they take the antihistamine while getting allergy shots that it doesn’t cancel out the allergy shots. It is proving that the allergy shots actually worked!

If the allergy shots didn’t work because the patient was on antihistamines, then they would have reacted similarly to the group without antihistamines.

This is because their immune system would not have been built up to the bee venom (Due to the antihistamine countering it) and they would’ve had a reaction.

This study is proving that the allergy shots are unaffected by the antihistamine use. But in conjunction, these two prove incredibly useful!

Most Places Do Not Care If You Take Antihistamines Or Not

At most places you are receiving allergy shots or allergy immunotherapy- they do not care if you take antihistamines or not.

This means if you decide to take them, or do not decide, it won’t change anything.

They’ll still give you the shot and give you treatment as needed even if you have a severe reaction.

However, I personally recommend taking your normal antihistamine for a very important reason.

Reduces Chance of Reaction + Possibly Death

So here’s the thing. Allergy shots are actually serious business.

This is why every place you get allergy shots at requires you to stay 30 minutes after- because this is when the majority of reactions happens.

So when you are taking an antihistamine, it is reducing the chances you have a severe or bad reaction to the shot.

A bad reaction can include you going into anaphalytic shock and possibly dying.

This is the entire reason you have to stay that 30 minutes. That way the staff can notice if you’re having a reaction and they can save you from death by giving you things like epinephrine. (Epi-pen/other antihistamine drugs).

When you’re taking an antihistamine, you’re just helping yourself out. And as we learned before, taking an antihistamine won’t actually harm your allergy shot progress. So there’s no downside to taking it.

Many Clinics Offer The Antihistamines For Free

Many clinics actually offer the antihistamines for free for their allergy shot users.

Obviously this depends on your own clinic- every clinic does things a little different. But in general, for most immunotherapy patients they offer antihistamines for free to take with your allergy shots.

Just ask your provider the next time you get your shots their policies. This is excellent if you are worried about the cost.

Look- I know first-hand allergy antihistamines can cost a lot. That’s why I personally order my antihistamines from Amazon, where it is nearly $10 cheaper!

But if you need a way to save money, this can be a godsend if you don’t want to be taking some of your top-tier stuff due to the number in your bank account.

(Nobody even talks about how unfair us allergy sufferers have it. Like seriously, I have to spend a good $60/month on antihistamines)

Always Verify With Your Provider

So I read online that actually some places have the patients not take antihistamines to judge some of the reactions.

This is mainly for people with things like seafood allergies or other more ‘severe’ things than just like a tree allergy.

I think this is so they can write down and measure how exactly the body is reacting to the shot and measure the change. This is likely to ensure that someone can feel better about eating seafood or other things.

For the vast majority, you’re good to take an antihistamine. But if you’re in a special program like that, verify with your provider.

I just simply called up the clinic and asked the person at the desk. She just called over a health technician and got an answer for me quickly! Awesome!


So, can I take antihistamines while getting allergy shots? Yes! In fact, it’s more beneficial to- and they don’t harm your progress at all. This is only different for some people in special programs, so always verify with your provider.

And if you forget- don’t fret. Many clinics offer the antihistamines for free!

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