If you split a ‘sustained release’ pill in half, do you get half the dosage for the same length of time, or the full dosage for half the length of time? Or something in between?
How does sustained release work, in pills? I assume they do something like encapsulate the medication in material that dissolves at different rates, or something like that. I’ve always wondered about this. Anybody know?
Now that I have asked, I will go Google, the better to come back here and cast my knowledge upon the waters.
My guess as to how it’s done was (more or less) right; so, I would postulate that the answer to my original question is that a sustained release tablet cut in half would release half the dosage over the same length of time, provided it was one of the solid-form pills.
“In some SR formulations, the drug dissolves into the matrix, and the matrix physically swells to form a gel, allowing the drug to exit through the gel’s outer surface.”
If this is the case, it seems like the critical issue is the surface area exposed to stomach acid, in which case, it seems more likely that you’d get the full dosage for half the length of time.
I understand that the method is encapsulating the active ingredient in some substrate that either has to dissolve, which can be divided into different substrates with different dissolution rates, or that slows release through diffusion.
It’s obvious that the total medication released after all is said and done will be the same whether you cut the tablet or not.
I think cutting the tablet in half and consuming both will give you a dose that is somewhat stronger at first and tails off faster.
It depends on the pill, it depends on the coating, it depends on the bioavailability and absorption rates of the drug in the stomach, upper and lower GI, etc. There is no one answer to this.
Note that for most drugs, no one knows what the dissolution/absorption rate is for a tablet that has been cut in two. Not even the pharma companies, because there is no reason to study such a thing. Unless a tablet is scored (and therefore intended to be cut in half), half a tablet will never be tested in any laboratory/quality control/clinical trial test. Cutting a non-scored tablet means you are taking it in a method contrary to what it is indicated for, and the results are therefore unpredictable and unknown. It is not recommended to cut or even crush a tablet in order to take it. If you need a smaller dose, see if you can get another dosage form, or if one isn’t available, have your doctor consider an alternative medication.
Possible outcomes of cutting a tablet in half:
nothing, and it behaves the same way as a whole tablet, with half the drug absorbed in a similar amount of time, etc.
Cutting a tablet results in there not being any protective coating on the exposed face of the tablet. Most long-acting/sustained release drugs are designed to be released and absorbed in the GI tract, and the coating protects the drug from stomach acid. Exposing the drug to the stomach can mean that the drug gets attacked and degraded in the stomach, thereby rendering it useless or perhaps even toxic/otherwise unsafe. Alternatively, the drug gets fully absorbed immediately and the patient is possibly exposed to too high a dose in their blood, suffers effects from a high dose and doesn’t get the benefits of a long-term release.
Half a tablet undermedicates the condition for which the patient is taking the medication in the first place.
The important thing to remember is that the drug has been studied/developed and proven in the form in which it is packaged. There is no information available on the drug in any alternate form such as cut or crushed. Even quick-acting drugs shouldn’t be altered, for the same reasons as long-acting ones.
There are many different ways to make a medication “sustained release”, which as mnemosyne said, makes it depend on the medication and/or coating. There is no one answer to give, and all I can make are generalities. The important thing is to never just cut a sustained release medication in half unless it’s scored. Before you cut any unscored tablet (sustained or immediate release), it is best to ask your pharmacist if that particle tablet can be cut.
Generally though, there are a couple popular methods to make a medication sustained release, they are:
Coating: putting a coating on the tablet to keep it from dissolving all at once.
Dual-layer: Having a layer of medication on top, then a special barrier that delays when the drug is release, then another layer of medication under that.
Salt-form: Changing the salt the drug is combined with, most common is changing to polistirex or succinate. Polistirex is used with drugs like Tussionex and Delsym (Delsym is dexomethorphan polistirex, while other cough suppressants have dexomethorphan hydrobromide).
My personal favorite, Osmotic release forms. This is most commonly used with Budeprion XL (Wellbutrin). The tablet is an semi-permissible membrane that allows water through, but nothing else. There is then a little tiny hole that is lasered into it. Water enters the tablet, and the drug is then pushed out that little hole releasing the medication at a predictable rate.
There are other ways, but these are the more popular ones that I can think of off the top of my head. Hope this answers your question. Remember though, talk to your pharmacist before splitting any unscored tablet!
I have very recently gone from 2000mg/day of Metformin to 1500mg/day of Metformin ER.
The ER’s are not available in 750mg so I got 500’s and a pill cutter and I take 1 1/2 twice per day.
I can tell by my sugar reading if the dosage is too low (I “self-medicated” and tried 1000mg/day, it was too low) and cutting the ER’s works for me.
you can get 500s, and take a 1000 and a 500 you know …
You just get your doc to write the scrip as x 1000 and x 500 tablets.
I get several meds where i take 2 different dose pills. You just have to keep track of what you take =) I get these great pillboxes that have 4 daily dose sections and divvy my meds up [I take meds at 5 am, 1 pm, 5 pm and 9 pm to allow for 1x per day 2 x per day and 3 x per day meds]
Hey, that reminds me of a very important point. There are time-release pain killers based on how long it takes the med to diffuse or dissolve, and if you chew one of these you can get a dangerous dose too quickly. I think Oxycontin is one of these (this being a trade name for oxycodone in a time release format).
I am not sure I remember right, but I think maybe I read that the strongest ones can deliver a fatal dose. Though, it seems surprising that they’d prepare a pill that was so easily made so dangerous, and this may well be incorrect. Anybody know about this one?
Everybody please relax. This is a hypothetical rather than real-world question. I’m not trying to figure out how to get high off baby aspirin or something.
Your intent is irrelevant. Baby aspirin or high-dose morphine tablets; makes no difference. They are subject to the same laws and regulations and similar testing from discovery through development, onto the market and beyond. A crushed or split tablet that was not scored (and therefore intended to be split) has never been tested, even if it hypothetically amounts to the same dose otherwise available in another tablet. As the CEO of my former employer used to say, “chemistry happens” and chemical reactions and their effects on the human body can be very hard to predict. By taking a medication - any medication - in a way other than instructed, you (general you) are taking a chance, however slim that may be. There is no data to guide you, and consequently no data to protect you.
It might be worth noting, however, that when a tablet/gelcap/cream/ointment/injectable/suppository/etc is developed, the molecule of interest is exposed to things such as acid (stomach acid), base, light, heat, cold, water and various other chemicals it might come into contact with and the final recipe is based upon that. The final recipe and dosage form takes into account whether the drug molecule will survive the stomach or not, amongst other things. Crushing or splitting a tablet removes that part of the process. The tablet is no longer what it was, and that means “chemistry can happen”.
Actually I hate splitting tablets even if they are scored … no matter how carefully I use the damned pill splitter I have, the halves are never equal, and there is always some powdery loss … I am OCD enough that not having the exact same size pill halves [and the missing powdery bits] bother the bejebus out of me.
I haven’t done a lot of work with scored tablets, but I do know that in theory, each half should be equal in the sense that both deliver half the label dose (e.g. 50mg each for a 100mg whole tablet, +/- 2%). I’ve done average weight testing on scored tablets, and half the weight +/- some percent (probably 2, I don’t remember) should be distributed to each half. I really don’t know enough to give you much feedback on that!
The only pill I’ve split at home (cetirizine HCl) seems to split evenly, but I just do it by hand, not with a splitter. I remember splitting one at work that was intended for dogs…it was scored for quarters! Rather easy to do; pill score down on a table and push in the centre! Kind of cool when you think about it!
You have to be careful with trying to portion any dosage form that’s not straight-forward immediate release. In many of them, the delayed release or sustained release is mediated by a special coating, and if you break the tablet, you wind up having the medicine all release at once, right away. Others are homogeneous, but there’s usually no way you can tell which is which just by looking at it.
Capsules are a little more predictable in this sense, as usually the coating is on each capsule pellet individually. So you could divide the pellets in half and have a reliable half dose.