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c/reconstitution·submitted 2 years ago by u/elin_ferrari

unpopular opinion: most of what gets said here about concentration is guesswork

PSAbranch of 9 comments

unpopular opinion: most of what gets said here about concentration is guesswork. Change my mind, genuinely — I have no stake in being right about this. The failure modes I have actually seen posted here, in order of frequency. One: reconstituting at a different volume than intended and not writing it down, so the…

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This branch

9 comments, started 2 years ago
u/units_not_mgMOD160 points·2 years ago

Reminder: this board does maths, not dosing. Nobody here tells another member what amount to take.

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u/clara_weiss71 points·2 years ago

more water is not more drug, it is the same drug in a bigger volume

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u/elin_ferrariOP87 points·2 years ago·edited

Small fix — a U-100 syringe is 100 units per mL. If yours is marked differently it is not U-100 and the whole calculation changes.

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u/elodie_grimaldi27 points·2 years ago·edited

Small fix — a U-100 syringe is 100 units per mL.

This is the sentence that makes the rest unnecessary. Write it on the vial and the problem is gone.

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u/tomas_kimani87 points·2 years ago

Careful — that arithmetic is wrong. 5mg in 2mL is 2.5mg/mL, so 1mg draws to 40 units, not what you wrote.

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u/hedda_adeyemi0 points·2 years ago

What is written on the vial right now?

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u/yusuf_nakamura1 point·2 years ago

This. Showing the working is the fastest way for somebody else to spot the mistake.

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u/elin_ferrariOP-32 points·2 years ago

What concentration did you actually reconstitute at, rather than what did you intend to?

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u/georgi_adebayo1 point·2 years ago

swirl, never shake

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About c/reconstitution

The arithmetic and the technique. Bacteriostatic versus sterile water, reconstitution volume as a concentration choice, converting mg/mL into insulin-syringe units, dead space, swirl-not-shake, stopper coring, and how long a reconstituted vial is actually good for. Math errors get corrected fast and politely.

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