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My grandfather used to eat grapefruit every day, but had to give it up when he was prescribed Warfarin (a blood thinner). Ironically it seems that it would have

My grandfather used to eat grapefruit every day, but had to give it up when he was prescribed Warfarin (a blood thinner). Ironically it seems that it would have been just fine for him to continue so long as he stuck to religiously eating grapefruit every day. He would have needed a substantially lower dose of the drug, but Warfarin is one where you adjust the dose a lot for each patient anyway: the manufacturer recommends starting with 6mg and ending up anywhere from 0.5 to 10mg depending on the patient's response [0]. He was also hospitalised several times, both for his heart problems and stomach cancer. I wonder if hospitals keep grapefruit on hand for patients like this, or if they ban it altogether. [0] https://www.nps.org.au/australian-prescriber/articles/how-to-manage-warfarin-therapy https://www.nps.org.au/australian-prescriber/articles/how-to...

jalk 6y ago
> the manufacturer recommends starting with 6mg and ending up anywhere from 0.5 to 10mg depending on the patient's response I tried to explain binary search to my gp when she was trying to find my dose of thyroxin. Unfortunately, according to her, a too high does carries a lot of unpleasant side effects - so linear search it was.
- vikramkr 6y ago
  Yeah, binary search where you don't know what the upper bound is with a narrow therapeutic index drug is not necessarily the best option
- buddhiajuke 6y ago
  We pretty much did binary search to find my lithium levels. The lethal concentration of lithium is very close to the therapeutic range, but we couldn’t afford to spend long on low doses (since you have to take blood tests to assess effective dosages.)
  - krageon 6y ago
    If you keep a good diary you can limit the blood tests to 1-2 times per year and assess therapeutic effect using self-reporting.
buddhiajuke 6y ago
My dad used to take warfarin too and keep a very steady diet of dark leafy greens (his poison of choice he wouldn’t give up). There are meds now that are less dependent on food, your grandviejo may want to ask about.

jalk 6y ago

> the manufacturer recommends starting with 6mg and ending up anywhere from 0.5 to 10mg depending on the patient's response I tried to explain binary search to my gp when she was trying to find my dose of thyroxin. Unfortunately, according to her, a too high does carries a lot of unpleasant side effects - so linear search it was.

vikramkr 6y ago
Yeah, binary search where you don't know what the upper bound is with a narrow therapeutic index drug is not necessarily the best option
buddhiajuke 6y ago
We pretty much did binary search to find my lithium levels. The lethal concentration of lithium is very close to the therapeutic range, but we couldn’t afford to spend long on low doses (since you have to take blood tests to assess effective dosages.)
- krageon 6y ago
  If you keep a good diary you can limit the blood tests to 1-2 times per year and assess therapeutic effect using self-reporting.

buddhiajuke 6y ago

My dad used to take warfarin too and keep a very steady diet of dark leafy greens (his poison of choice he wouldn’t give up). There are meds now that are less dependent on food, your grandviejo may want to ask about.