Just did my first reconstitution and I think I messed up — anyone have experience?

anders_CPH said:

Dead space is the answer to the missing dose.

I am going to disagree with reconstituting low as a general rule. More diluent, more punctures, more in-use days at room temperature, and the stability trade-off is real. Precision is not the only variable being optimised.

Correct me if the detail matters more than I have assumed.

pete_manc_UK said:

I reconstituted a 10mg vial with 2ml of bacteriostatic water and I want someone to check my unit arithmetic before I draw anything, because I keep…

dosing arithmetic — critical reminder about tirzepatide dose equivalence across formulations:

Mounjaro KwikPen and compounded tirzepatide are the same molecule but:

• KwikPen is ready to inject, no mixing needed
• Compounded requires reconstitution and proper syringe technique
• Verify your compounded concentration before each injection
• Never assume 1 vial = 1 dose without checking the math

PharmD_Rodriguez said:

I am going to disagree with reconstituting low as a general rule.

Bacteriostatic water quality matters for dosing arithmetic reconstitution. Not all BAC water is created equal:

• Should contain 0.9% benzyl alcohol as preservative
• Must be sterile and pyrogen-free
• Should come in a sealed, intact vial
• Check expiration date — yes, BAC water expires
• Store at room temperature, protected from light

I buy from a reputable medical supply company, not Amazon marketplace sellers. The $3 savings isn't worth the infection risk from unverified BAC water.

One thing that is still open after pam_columbus’s answer:

How much material I am losing to dead space, and whether that explains why a 10mg vial gives me nine usable draws rather than ten?

OP back with an update, since a thread like this is useless without one.

Resolved. I wrote mg, ml and mg/ml on the vial in marker and did the division in that order, and the two of us now get the same number every time.