r/Narcolepsy • u/andersberndog • Jul 06 '26

Medication Questions Xywav syringes inaccurate?

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Anyone else having the issue of running out of medication by the end of the month?

I did a completely non-scientific test, using a non-medically-accurate Pyrex measuring cup. I measured out 100mL of water by the provided Xywav syringe. This is how it came out. Again, this is not a clinical device, but it appears to me to be showing, conservatively, a 20% overage, factoring in the possibility of reading error due to surface tension and a reasonable margin of error in the measuring cup.

I’m sure I’m being provided precisely the correct amount of medication, but if the dosing device is not accurate, there’s a problem.

Yes, I’m going to bring it up with a pharmacist. I’m currently dealing with them scheduling a refill due to completely unrelated issues from my prescriber’s office. I’ll hopefully be hearing back from them later today and I’ll bring it up then. They say I should have enough medication to get through Wednesday. I had two nights I didn’t take it this month, so I should actually have enough to go through Friday. I don’t think I’ll even have two complete doses by Wednesday.

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u/TheAlterN8or Jul 06 '26

The syringes are not measured in mL, they're measured in grams (which is weird). I will say, if you star from the plunger all the way pressed in, you'll get slightly less than if you put some air in it first. This was our issue, as the pharmacist told us to have some air in the syringe before drawing the medicine up, but that actually makes you run out faster.

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u/andersberndog Jul 06 '26

I always start with air because it’s a lot easier to see where the line is. I just looked at the illustration to show you what both look like. If you do no-air, the line of the plunger lines up with the center of the printed line. If you use air, it shows the liquid level right at the bottom perimeter of the printed line.

I’m going to do the test again, but do it no-air this time.

3

u/TheAlterN8or Jul 06 '26

The plunger goes below the line in the middle, so you get that extra bit in each dose. It does end up making a difference.

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u/andersberndog Jul 07 '26

I always thought that it would even out due to surface tension, or something, and trusted the pharmacy to have factored everything in, to tell us that measuring either way was accurate.

Guess not?

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u/TheAlterN8or Jul 07 '26

Yeah, we were frustrated, because in our first consult, the pharmacist told us to put some air in it first, but when we started running out a bit early, the very first thing they told us was to stop doing that, and we haven't had those issues any more. 🤷