Is it better to take a 24-hour allergy pill in the morning or at night?

February 23, 2008 5:15 PM

Does it matter if I take a 24-hour allergy pill at 10am or 10pm as long as I take it at the same time every day?

Part of my brain says that taking the pill before I sleep will give it more time to start being effective while another part of my brain says that sleep acts as a kind of reset switch and will weaken the pill's overall effectiveness. Am I just overthinking the issue or is there an advantage to taking the pill at a certain time of the day?

posted by richrad to health & fitness (12 comments total)

Some antihistamines cause drowsiness so if you're taking one of those it is probably better to take it at night. Other than that, though, it shouldn't matter much.
posted by Justinian at 5:21 PM on February 23, 2008

Assuming that the pill is absorbed into the bloodstream relatively quickly, the bioavailability will be highest shortly after you take the drug, and taper off slowly throughout the 24-hour period. (This may differ in a few medications, which are designed to be absorbed slowly, or coated so that they are absorbed some length of time after ingestion)

So no, sleep does not "reset" the drug's activity in anyway.

What I keep in mind when taking my 24-hour allergy pill is that the concentration of the drug is going to be lowerst right before I take the pill, and that's when my symptoms will be worst. Since waking up with a stuffy head is a shitty way to start the day, I generally take the drugs at night. You can come to your own conclusions about what timing is right for you.
posted by chrisamiller at 5:21 PM on February 23, 2008

It's just a matter of when you mind the worst symptoms (which will be during the period before you take the pill) the least.

Personally, I take a pill when I have symptoms, not at a certain time of day. When I was taking them daily, I tended to opt for morning just because I take a non-drowsy formulation which would interfere with getting to sleep.
posted by joannemerriam at 5:58 PM on February 23, 2008

They don't really tend to last 24 hours for me, so I take mine in the morning and then they taper off at night. I just deal with the stuffy head in the morning thing. YMMV.
posted by streetdreams at 6:28 PM on February 23, 2008

If the pill can be cut, you could probably take half, twice a day. That would give you the most constant blood level of the drug.
posted by Malor at 6:29 PM on February 23, 2008

You dont want to cut a time-release capsule, nor do you want to take anything like claritin-d near bedtime.
posted by damn dirty ape at 6:33 PM on February 23, 2008

IANAD, but MDIAD (my Dad is a doctor, ha), and he says that 24 hour allergy pills like Claritin absolutely don't last for 24 hours. For patients with severe allergies to dust, mold, and pet dander, he often prescribes two 24 hour pills per day. He says it doesn't matter when you take them- you can take both together or one in the morning and one at night and it won't matter, but that some patients experience greater effects by taking the pill(s) in a certain way because of the placebo effect.

For example, if you think that the pill(s) work better when taken twice daily, you should do that, because it probably is working better.

Personally, when I'm taking my Claritin I take it in the morning, because I want it to be more quickly bioavailable and hypothesize that the drug has a greater and more complete bioavailability in the morning when I'm usually more active and my stomach is digesting, but not full of food. Works great for me, but it could just be the placebo effect.
posted by arnicae at 6:38 PM on February 23, 2008 [1 favorite has favorites]

I take my 24-hr allergy pill as soon as I wake up in the morning. This means I'm asleep during the time when the drug is least effective. So, I don't feel my symptoms when they are at their worst. Furthermore, by taking them as soon as I wake up, the drugs have started to kick in by the time I'm ready to head out the door.
posted by oddman at 6:55 PM on February 23, 2008

With no evidence presented, my allergist told me that my allegra-d is more effective if I take it in the morning.
posted by drezdn at 6:56 PM on February 23, 2008

I should add that it depends on what you're allergic to. I'm allergic to dust mites, which thrive in bedding and pillows, so it's natural for me to take the pill before bed.

If you're allergic to mold or pollen, and mainly have problems outdoors, it may make sense to take in the morning.
posted by chrisamiller at 7:30 PM on February 23, 2008

IANAD also, but family members have been on every allergy drug invented in the past 30 years. I take mine at night because they make me pass out, and around here it's a 5-10am thing that really messes with me. Double dosing the 24 hour stuff with one in am and one in pm is pretty common. You have to play around a bit, took me 3 months to figure out when to take it and how much to take. I mix in the fake sudafed instead of the '-D' versions, works well enough and less likely to be 'wired'.
posted by zengargoyle at 10:10 PM on February 23, 2008

I have taken Zyrtec, and was always told to take it at bedtime, or during the evening. That was you were sleeping during the first part (when the medication is more likely to make you feel sleepy).

Ask your pharmacist. YMMV.
posted by 6:1 at 11:01 PM on February 23, 2008