Medicine and half-lives

I don't always take pain medication But when i do, I take more ...

People are often wondering why they need to keep taking their medication or why something hasn't worked yet or if they need more than what they've already taken so I just wanted to go over the broad strokes around that. I will try to do some follow up topics too.

Anything you put in your body, it tries to get rid of. It is used as best able by your body and the body then tries to spit out all the garbage that's leftover. That's the reason for why you go to the bathroom and why we die when we stop eating.

The same is true for all medications. Talking mostly about pills, any medications put into your body take about 30-60 minutes to get through your stomach and to your small intestine where it's absorbed. There are some medications you need to take by themselves or in relation to meals or without other medications because there can be interference with how stomach acid affects them and how they are absorbed in the intestine.

Once a medication gets into your system, your body starts trying to get rid of it using the kidneys and/or liver. That's why for many things you need to keep taking the medication.

How often and how much of a medication you have to take depends mostly on it's half-life, which is the amount of time your body takes to reduce the medication concentration by half. A rule of thumb is that it takes about 4-5 half-lives for a medication to reach a steady state.

As a for-instance, Synthroid (levothyroxine) is for people with low or non-existent natural thyroid hormone levels. It's half life is 6-7 days, so when there's a dose change, it takes 4-5 weeks for the medication to reach a steady level. For that reason, while we typically have people take it daily, you can theoretically take a week's dose all at once and it would work out the same, although initially can make people feel a little jittery for a day or two.

On the other side of things, ibuprofen has a half life of 90-120 minutes so it needs to be taken more frequently to reach a steady state, often three times per day. There's a little piece about this here with a nice graphic.

NSAIDs

Advil and Motrin are ibuprofen, then you have Aleve (naproxen). Those are the over-the-counter ones. Prescriptions are Mobic (meloxicam), nabumetone, indomethacin, Toradol (ketorolac), diclofenac, Lodine, and the list goes on. All of these medications are in a class called non-steroidal anti-inflammatory drugs (NSAIDs). I'm giving you this list because there is mounting evidence that these medications a) don't work as well as we'd thought and b) have some very serious long term side effects we're finding out more about. NSAID's act by reducing the amount of prostaglandins you make in order to reduce inflammation. However, prostaglandins have a ton of other effects and are involved in the maintenance of just about AIDs and also stronger if they are taken every day and/or around-the-clock. every other organ system that you have. The effect is stronger with higher doses of NS NSAID's work best and are best indicated for times when something is r...

Kidney Stones

I've written about this previously , but it's often hard to explain to people what a 10 is on the "1-10" pain scale if they haven't been in that spot before. For women who have had children, they generally know what a 10 is, but for men it's a little harder. When I was a medical student on my psychiatry rotation, we had a patient calmly sitting there saying his pain level was at a 10 and our resident, who was an ex-military sniper with a large skull tattoo on his forearm and a crosshair through the eye, calmly leaned forward and asked, "so if I lit you on fire and ran you over with my truck, you could not be in more pain than you are now, correct?" The patient changed his answer. Getting to the point, a kidney stone is about the close I can come to describing a 10/10 pain to people who haven't gone through childbirth. The fundamental issue is similar - your body is trying to move a big solid thing through an opening that was not really desig...

Pain

Sorry to be a pain I would say about 90% of the comments I hear from people about their pain threshold is that they think they have a high pain tolerance. Which is statistically impossible unless I just attract people who have a high pain tolerance. We traditionally ask people to rate their pain on a 1-10/10 scale and while we hear a lot of 9's and 10's, I would say that, having been present for a number of them, a 10/10 would be giving birth to a first child. For those who haven't experienced that, my old psychiatry resident described it as "so if I lit you on fire and ran you over with my truck, you would not be in any more pain than you are now" (he was also a former Marine sniper which might explain that). But this is pretty pervasive throughout the medical system and got me wondering as to how people's understanding of what their pain threshold was matched up to what it really was. Fortunately, there were researchers who had a yen to poke peopl...

Hey Doctor Scott ...

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