Effects of fexofenadine, diphenhydramine, and alcohol on driving performance | Hacker News Reader

Effects of fexofenadine, diphenhydramine, and alcohol on driving performance

pubmed.ncbi.nlm.nih.gov

36 pointsjasonhansel61 comments

2nd gen antihistamines (Fexofenadine, Cetirizine, Loratidine) are definitely what you want for allergies. 1st gen like Benadryl/Diphenydramine have awful side effects. I highly recommend nasal sprays like Fluticasone as well, available OTC in the US these days and amazing stuff.

Fluticasone changed my life. It's a wonder drug.

I would argue that, whatever “generation” it is, cetirizine does not deserve credit for being second generation. I know plenty of people with extremely obvious CNS effects from it. In contrast, loratadine seems innocuous.

Second that, cetirizine definitely feels more like clemastine or meclizine than a proper second gen "non sedating" antihistamine. And with hay fever AND an allergy to nuts, I've tried them all, haha.

Unfortunately its justifiably classified as 2nd gen and IIRC studies show that it's generally more effective for hay fever. Personally, I've found that loratadine is pretty ineffective, especially after regular use.

I found loratadine very effective but it takes time to work. At least a week

For me, loratadine was ineffective, and I can't distinguish cetirizine and fexofenadine - both are maybe 50-60% effective with no notable side effects, and allergy season means extra fatigue no matter what. Cetirizine does have the shortest half life.

Cetirizine is a "no go" for pilots. Fexofenadine and loratadine are OK to fly on though, as is fluticasone.

+1 to Fexofenadine (Allegra) and Fluticasone. Loratadine (Claritin) is too weak for my needs and Cetrazine (Zyrtec) has side effects are too similar to a stimulant for me.

> Fluticasone

A corticosteroid, it has awful side effects as well

Maybe. But I would say for me the benefits of not suffering "breakthrough" hayfever attacks far outweigh the side effects.

Antihistamines are great - but the nasal corticosteroids are what really control my hayfever (1) when used consistently.

1 - Hayfever so bad that I used to have to get custom serum shots containing the local pollen profile, every 2 weeks as a kid. Had anaphylaxis twice.

Best to limit corticosteroids if you can. Azelastine was approved to go OTC last year and is a half-decent antihistamine nasal spray. Hopefully it will be available stores this summer.

Nothing works quite as good as a corticosteroid of course, but azelastine controls my symptoms without having to rely on steroids.

Administered nasally it has very poor systemic bioavailability.

I thought so at first. My personal experience was different though.

Ironically, whilst having terrible hayfever... Not taking Antihistamines at all seems to have had the most profound effect on me between the gen 1 and 2 meds. If I didn't know any better, I would almost figure I was having some sort of rebound effect from taking them in the first place. Which is odd, because I have been diagnosed with having Allergic Sinusitis, which triggers an inflammatory asthma if not careful.

I used 1st gen stuff like Chlorpheniramine and Diphenhydramine to start. Tried some second gen stuff not too long ago, and it worked pretty well too; but not as well just not taking any? It's weird. Meanwhile if I have an actual allergy attack, I keep Benadryl around for just in case. Because again, not taking any of these seems to just leave me without any allergies now? Or as bad at least. But Benadryl seems to still have some effect, where as I need a couple days of taking the 2nd gen stuff to actually get any effect; if any at all.

All in all, I'm confused now as to which I should even take considering everything in how my reactions have been to it all. So I just don't take any unless things are real bad now. Which they usually aren't.

Maybe I outgrew my allergies? I doubt it, cause I still sneeze around cats and stuff. heh.

These are great. Europe has some even newer 2nd (or "3rd gen") antihistamines such as bilastine and rupatadine. They're apparently even more effective than what we have in the states.

Would love to try them out, but unfortunately I don't think they're seeking FDA approval. Anyone abroad have any experience with these compared to loratadine/cetirizine?

Beware of corticosteroid side effects [0][1]. Not stated directly here is retinopathy

[0] https://www.mayoclinic.org/drugs-supplements/corticosteroid-...

[1] https://www.mayoclinic.org/drugs-supplements/corticosteroid-...

50mg diphenhydramine is quite a bit! Anyone who has ever taken that amount for sleep effects will tell you so.

It is, but 25 - 50 mg every 4 - 6 hours, with no more than 200 mg over 24 hours, is also the instructions on the OTC bottle I have.

I made that mistake once in university. Took two capsules for a moderate skin reaction and slept the entire afternoon away. Fortunately I was at home! Just willing myself to get up long enough to disrobe and turn the lights off was excruciating.

Look on Reddit some people are taking much much more recreationally and the usage reports are pretty daunting.

FYI: Antihistamines : https://psychonautwiki.org/wiki/Antihistamine

Diphenhydramine : https://psychonautwiki.org/wiki/Diphenhydramine

One not mentioned on this page is dexchlorpheniramine. In my personal experience, exceeding the recommended dose and fighting the drowsiness effect leads to quite a pleasant high and mild aphrodisiac effect.

That’s kinda interesting. I’ve only ever heard of DPH and Doxylamine (which I’ll on occasion use as a terrible sleep aid). I knew other antihistamines exist, but was never curious about their effects.

Added to the information on Antihistamines : https://en.wikipedia.org/wiki/Antihistamine

Prescription Drug Information, Interactions & Side Effects : https://www.drugs.com

drugs.com posted by 'omarhaneef' <-thanks-> : https://news.ycombinator.com/user?id=omarhaneef

>One not mentioned on this page is dexchlorpheniramine. <

  Yes, I'm afraid the site is not comprehensive, and a bare-bones entry at wikipedia;

Dexchlorpheniramine : https://en.wikipedia.org/wiki/Dexchlorpheniramine

Indeed that article is very bare-bones.

I was definitely surprised to find basically nothing about (ab)using dexchlorpheniramine recreationally after noticing the effects over dosing had.

I can't imagine trying to drive for an hour after taking diphenhydramine. It usually knocks me out hard within 20 minutes.

This is the context I was missing (brand names)

https://www.drugs.com/ingredient/diphenhydramine.html

Yes, it's marketed as ZzzQuil an OTC sleeping aid! (as well as benadryl)

Is 60mg a typical dose of fexofenadine? I'm only familiar with it as 180mg tablets (I was initially prescribed 180mg twice daily for dermatographic urticaria, and currently take 360mg twice daily).

60mg is the dosage sold for "12hr". 180mg is the "24hr" dosage.

I didn’t see it in the abstract but how are the alcohol and placebo administered? If they were ingested the participant surely knew they got alcohol or a placebo. And I assume that may have some impact on their performance aside from possibly being intoxicated. I suppose all 4 could be IV administered, but it doesn’t sound like that.

Well, you can give non-alcoholic beer to the subject telling them it is a real thing. Or make them a cocktail, such as Mojito, just a virgin one. Or the opposite: give them a soda secretly spiced with vodka. The possibilities are endless. But the problem is: people usually are familiar with how being drunk feels (and 0.1% BAC is pretty drunk), so it's almost impossible to hide the fact from them. So I guess "placebo group" is only with relation to drugs, not to alcohol.

> But the problem is: people usually are familiar with how being drunk feels

The problem is people know how alcohol tastes. Have you ever had a non-alcoholic beer?

There are alcoholic beers that taste as bad or worse as the non-alcoholic ones.

And there are alcoholic drinks that taste like they have no alcohol in them at all. Or drinks where you cannot tell if they have any alcohol in them.

There are ways to make these things blinded.

> Or drinks where you cannot tell if they have any alcohol in them.

Proving this for a sample is pretty much impossible because you’re simply masking it and the sensory performance of humans is highly variable. You can get some imperfect approximation of blinding but it will be a compromise.

You can still control for this, by having the participants taste both drinks, in a blinded manner.

If they can still somehow taste the difference between them, then you change your mix so that they can't tell the difference or eliminate them from the study.

This may have other effects on the study, but at least you can be reasonably sure that no one can tell the difference between the substances being tested, except possibly by the effects they feel after consuming the substances in question.

Encapsulated 'freeze dried alcohol' aka 'powdered alcohol'

<https://html.duckduckgo.com/html/?q='freeze dried alcohol' '...>

> If they can still somehow taste the difference between them, then you change your mix so that they can't tell the difference or eliminate them from the study.

This has lots of problems, not least of which it is assuming you could afford to tweak your experimental protocol this way all in the recruitment phase.

Do you have any examples in the literature where this is done?

At least for the study in question they used the method of swabbing a negligible amount of alcohol on the rim of the glass to attempt to fool all participants into thinking they were getting alcohol.

The article is extremely short, but comparing 2-4 OTC doses of diphenhydramine to a level of alcohol concentration above what constitutes a DUI in most places seems like an odd choice? Or is that just a matter of proof of concept, go for the big obvious demonstration first?

2 doses of diphenhydramine can have very noticeable and profound effects on many people, 50mg total isn't a light dose by any metric. That seems fine as a comparison to 0.1% BAC.

But 60mg Fexofenadine makes no sense to me in comparison. It's usually 180mg in a single pill.

Hate to break it to you, but 50mg is pretty much a common dosage for most people taking Diphen. At least where I lived over the past few decades... This is mostly due to the effect of 'if 1 pill is almost enough to do the job, then 2 pills should be adequate'. You see this a lot with people who take Tylenol and/or Advil. Tylenol overdoses are more common because of the frequency of acetaminophens use in other medications in combination with people taking Tylenol not realizing they are doubling/tripling their doses.

So having people end up driving on 50mg+ doses of the dryl is not uncommon in places like Canada. Pair it with a dose or two of pseudoephidrine hydrochloride as well, and you basically have a breath easy cocktail that might put you to sleep, or might keep you awake all night.

> So having people end up driving on 50mg+ doses of the dryl is not uncommon in places like Canada.

Yeah this makes sense to me. We have lots of people driving around at 0.1% BAC too.

The directions I'm looking at for a store brand diphenhydramine say to take 1-2 of the 25mg tablets as needed, so I'd expect that's the typical therapeutic dose.

Having done that for awhile once? It basically is, and that is the typically OTC recommended dose.

Sure, but you should always check basic mg/kg numbers before you take a drug. Diphenhydramine can be hallucinogenic in high doses.

They also sell 1-gram extra-strength Tylenol pills OTC, but that's a very high dose for an average person. And what do you know, acetaminophen is the leading cause of acute liver failure in the US.

What is your point exactly?

That typical OTC doses for a common antihistamine ARE probably equivalent in impairment to being legally drunk for most people is mine?

To play devil’s advocate:

People forget that drunk driving laws started as the result of activist campaigns from special interest groups only a few decades ago.

It is itself a victimless crime; we have existing laws against reckless driving, causing accidents, vehicular manslaughter, etc.; and as this study shows there are plenty of common, less regulated (i.e. showing no signs of impairment yet blowing into a measurement device cannot get you nailed) driving conditions which are as bad or worse than drunk driving.

It seems like a "victimless crime" in the same way that a hit and run is a victimless crime, as long as you get away with it.

Someone has willfully chosen to make life more dangerous for everyone else. It's possible they won't be caught, but ignoring the act carries a real possibility of harm.

There are people who would drive drunk every single day, if they could get away with it.

> hit and run is a victimless crime

Not clear on your logic. A hit and run has a victim: whoever is the owner of the person or property you damaged.

In contrast, a drunk driver who is not under excess influence of the alcohol in his system and who gets from point A to point B safely, has victimized no one.

>In contrast, drunk driver who is not under excess influence of the alcohol in his system and who gets from point A to point B safely, has created no victims.

And what of the drunk driver under excess influence who creates a victim?

presumably he is still subject to the laws that relate to creating a victim

I am sure the victim will feel very happy to have played their important part in finally bringing this scofflaw to justice.

The founder of madd in america thinks they went too far though.

https://www.washingtontimes.com/news/2002/aug/6/20020806-035...

> Candy Lightner, MADD’s founder, says she disassociated herself from the movement in 1985 because she believed the organization was headed in the wrong direction.

> “It has become far more neo-prohibitionist than I had ever wanted or envisioned,” said Mrs. Lightner, who founded MADD after her daughter was killed by a drunk driver. “I didn’t start MADD to deal with alcohol. I started MADD to deal with the issue of drunk driving.”

> Several years after she left MADD, Mrs. Lightner briefly represented the American Beverage Institute in its fight against the 0.08 percent BAC law. She also lobbied Congress to enforce tougher penalties for drunk drivers.

Maybe she took up that position after getting hired by the beverage industry or not I don't know but she did lose a child to a drunk driver. 0.08 is probably too strict as the consequences of that are really severe and as evidenced basically no more impairing than widely used daily antihistamines.

I would sooner drive after a couple beers with dinner than after taking Benadryl (diphenhydramine). That’s not because I think alcohol is safe to drive on.

I’ve used doxylamine (similar antihistamine) as a sleep aid and I wouldn’t trust myself to do much. It was hard just getting ready for work because of the brain fog the next morning.

Driving is inherently dangerous, regardless of impairment. Laws prohibiting drunk driving prevent excess deaths that would otherwise be commonplace if the practice were normalized.

I am in favour of total drug legalization (as consumption/possession are true victimless crimes) but impaired driving should remain prohibited. While it impossible to curtail all instances of impaired driving, we should aim to reduce its frequency where possible.

Shooting a gun into a crowd and not hitting anyone is also a "victimless crime", that doesn't mean it isn't high risk behavior that should be discouraged. The reality is that the large majority of drunk drivers are chronic drunks and drunk driving rules are pretty effective at taking them off the road.

>the large majority of drunk drivers are chronic drunks and drunk driving rules are pretty effective at taking them off the road.

That's a good point. Aren't you now arguing though that the vast majority of drinkers, who are not chronic drunks, be punished for the actions of a few?

The vast majority of drinkers, and this includes many of the chronic drunks, aren't being punished at all by these rules! Because they don't drive after drinking.

WTF, it's not a victimless crime. You have a much higher chance of getting in an accident and killing someone when you're drunk. Someone dies every 50 minutes in America from drunk driving accidents.

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