Ask Lemmy

27102 readers

4033 users here now

A Fediverse community for open-ended, thought provoking questions

Please don't post about current US Politics. If you need to do this, try [email protected]

Rules: (interactive)

1) Be nice and; have fun

Doxxing, trolling, sealioning, racism, and toxicity are not welcomed in AskLemmy. Remember what your mother said: if you can't say something nice, don't say anything at all. In addition, the site-wide Lemmy.world terms of service also apply here. Please familiarize yourself with them

2) All posts must end with a '?'

This is sort of like Jeopardy. Please phrase all post titles in the form of a proper question ending with ?

3) No spam

Please do not flood the community with nonsense. Actual suspected spammers will be banned on site. No astroturfing.

4) NSFW is okay, within reason

Just remember to tag posts with either a content warning or a [NSFW] tag. Overtly sexual posts are not allowed, please direct them to either [email protected] or [email protected]. NSFW comments should be restricted to posts tagged [NSFW].

5) This is not a support community.

It is not a place for 'how do I?', type questions. If you have any questions regarding the site itself or would like to report a community, please direct them to Lemmy.world Support or email [email protected]. For other questions check our partnered communities list, or use the search function.

Reminder: The terms of service apply here too.

Partnered Communities:

Logo design credit goes to: tubbadu

founded 2 years ago

MODERATORS

Is it safe to take a second pill a few hours after the first if the directions say "1 to 2 tablets?" (self.asklemmy)

submitted 8 months ago* (last edited 8 months ago) by TootSweet to c/asklemmy

20 comments fedilink hide all child comments

Over-the-counter diphenhydramine, for instance, at least in my country, says adults can take "1 to 2 tablets every 4 to 6 hours."

If you decide "my symptoms aren't so bad; I'll just take one" and then two hours later your symptoms are still bad (or worse), is it safe to take a second tab then? And if you do, should you wait until "4 to 6 hours" after taking the first tablet or the second to take an additional tablet? Does it depend on the drug? (Maybe it's fine for diphenhydramine but not for ibuprophen?)

I'd imagine blood levels of any particular drug tend to quickly spike and then exponentially decay back to undetectable levels. If you take two tabs, I'd imagine that graph is just twice as tall. If you wait a couple of hours between tabs, it's got two spikes and the second is a little higher than the first (but not as high as the two-tabs-at-the-same-time spike.)

If the concern is total concentration of drug in the bloodstream at any one point, a second tab a couple hours later is less of a concern than two tabs at the same time. If the concern is total area under the curve, then probably there's no difference between two tabs at the same time and a couple of hours between. If the concern is total time spent with a blood concentration of such-and-such, I could see there being more concern with taking a second tab just a couple of hours after the first.

And maybe there are other effects that I'm not aware of. Maybe if the blood concentration kicks up to two-tabs-at-once levels, the liver kicks into high gear, clearing the drug out quicker, but if you go a couple of hours between tabs, the liver neve kicks into high gear or some such.

And maybe this question hasn't even been well studied and maybe there's not really any good answer. But if there is, I'm curious.

you are viewing a single comment's thread
view the rest of the comments

[–] [email protected] 22 points 8 months ago (1 children)

A way that I find helpful to answer questions like this is to look backwards when taking multiple doses:

“If I were to take another pill now, would I have had no more than 1-2 pills in the last 4 hours?”

The pharmacokinetic questions are outside the scope of what the patient should be trying to figure out when taking a drug. That was the responsibility of the drug label writer and (if applicable) the prescribing physician and/or pharmacist. Yours is to faithfully follow the instructions, not make assumptions about drug residence time or loading doses.

[–] [email protected] 4 points 8 months ago

That’s a pretty reasonable perspective that will serve most people well.