medicine, drop size, and vampire blood

[cellio]

A recent mailing from my employer's department of reducing health-insurance costs (that's probably not their real name) offered some advice that seemed questionable to me. They suggested splitting pills -- not, they hastened to point out, that we should take half the dosage we need, but rather, we should get pills that are twice as strong as they need to be and then split them. They suggested that a stronger drug doesn't necessarily cost any (or much) more to fill, so you can fill your prescription half as often, saving you half the copay and them a lot on the balance. (Aside: what bright person decided that your cost, if insured, should be per month rather than per some volume? If I take a medicine twice as often as you do, why shouldn't I pay twice as much for it?)

I wonder how the pill-splitting scheme could actually be implemented legally and what doctor or pharmacist would go along with it. I find it hard to believe that a large company would advise its employees to commit insurance fraud (in a manner that's traceable), so there must be a way to do it, but I'm puzzled. (The company self-insures; maybe that's why it's ok?)

I was telling this to Dani last night, and commented that even if it's kosher I can't benefit from it for my prescriptions -- the medicine I take for glaucoma is in the form of eyedrops, and I don't know how to get double-sized drops. (Nor am I going to ask my ophthamologist to write a bogus prescription.) This, combined with some recent TV viewing, led us to wonder how big a drop is, anyway. We didn't have an internet connection to hand; Dani tried to work it out theoretically while I tried to work it out empirically. (Things often fall out that way with us.) A medicine that I take once a day (two drops) comes in a 2.5ml bottle and lasts about a month (maybe a little more). Viscosity matters, of course; this stuff is closer to water than to syrup. So I posited about 25 drops/ml for my medicine. (Google later suggested 20 drops/ml of water as an approximation.)

And that's when we turned our attention to the amount by which a character in the True Blood episode we'd just watched overdosed. The character had a quarter-ounce vial of an illegal substance (vampire blood) that he was supposed to take one drop of at a time. Wikipedia tells me that the viscosity of normal blood is about three times that of water. It has no data on vampire blood. Assuming (and I don't know if that's valid) that drop size is directly correlated with viscosity, this suggests that the character overdosed by a factor of approximately 46. Ouch. :-) (Yes, it did hurt.)

Ok, fine -- what have you done with your science education lately? :-)

Comments

[jerusha.livejournal.com]

Well, one reason why "take twice as much <> pay twice as much" is that, whatever pricing you're looking at [wholesale, retail, co-pay], a 100 mg pill is not going to cost twice as much as a 50 mg pill.

However, one should definitely check with one's pharmacist, because as ichur72 points out, some pills must not be divided or crushed, because of formulation issues (controlled release construction, coatings, etc). Your pharmacist could also tell you if the pill is scored or otherwise constructed with the idea of being divided.

When calibrating droppers, the USP standard dropper delivers 20 drops of water per milliliter. However, because, as you point out, the viscosity of different liquids differs from water, droppers intended for use with a particular liquid will be calibrated specifically to that liquid. With eyedrops, there is the additional consideration that, in the eye, medication is better absorbed in smaller drop volumes. (That is to say, if you have two formulations, one with 1 mg of drug in a 0.05 mL drop (USP standard drop), and the other with 1 mg of drug in an 0.03 mL drop, the 1 mg from the smaller drop will be better absorbed.) Basically, this is because the volume of the eye is limited; the excess volume of a larger drop drains away through the lacrimal system without ever coming into contact with the cornea. (Part of my day job involves helping to teach pharmaceutics, which is the science of getting drugs into dosage forms.)

[cellio]

Thanks for the information. Semi-coincidentally (it was a side effect of the eyedrop question), we found a useful discussion of glaucoma meds that mentions in passing what you said about the eye absorbing drops. I always worried a little that not all of the drop actually makes it into my eye; my doctor has told me not to worry about it but we never discussed why not. (My doctor is very good about answering questions and explaining things; it's just that this was farther down in the queue and we have limited time.)