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Practice · Administration · continued

Completing a dose with a second syringe, and the dead-volume arithmetic posts 61–77

This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1.

JF
j.fonsecaTL226 Jun 2026#61
cannula_drift, post #38: I have been on both sides of the completing a dose argument in this category within eighteen months, which should tell you how strong the evidence for either side is. Go to post

Air in the syringe is a much smaller problem subcutaneously than the anxiety about it suggests, and it is still worth expelling because the bubble occupies volume you meant to be liquid.

22 likes in reply to #38 1mo
PW
PharmNotes_WhitfieldTL4Pharmacist28 Jun 2026#62

Right, and stated more narrowly than I would have dared to state it.

0 likes 30d
FS
f.sjobergTL230 Jun 2026#63

Completing a dose sits at the boundary between what this community can usefully discuss and what it cannot, and I think it falls on the discussable side, narrowly.

3 likes 28d
DO
dr_okonkwoTL4 Moderator2 Jul 2026#64

Post #60 describes the usual case. This is about the unusual one.

An update on my earlier completing a dose post: the pattern held for another six weeks and then stopped, which I did not predict and cannot explain.

10 likes 26d
ML
m.lehtinenTL24 Jul 2026#65

Confirming post #63 from a second method, which matters more than confirming it from a second person.

If you have to inject at a different time of day than usual, that is a much smaller perturbation than it feels for a weekly compound with a week-long half-life.

If that is already documented somewhere, ignore me and link it.

16 likes 24d
CC
c.cardosoTL26 Jul 2026#66

The strongest argument against my own position on completing a dose, stated as well as I can state it, since nobody else has yet.

31 likes 22d
CL
c.lundgrenTL28 Jul 2026#67

Subcutaneous injection into abdominal tissue, thigh or upper arm is what the licensed labelling in this class describes, and the published comparisons found the differences in exposure between those sites small.

1 like 20d
NN
n.nybergTL210 Jul 2026#68
k.okafor, post #20: This follows post #17 rather than contradicting it. Where I have landed on completing a dose, having got it wrong once in public: the direction is clear, the magnitude is not, and anyone quoting a precise magnitude has borrowed it from somewhere that did not measure it. Go to post

Bleeding at the injection site: normal and usually minimal. A little blood at the needle site after withdrawal is not a reason to assume you lost a significant dose. The needle passed through tissue and there is a small amount of bleeding in the tract.

6 likes in reply to #20 18d
ML
m.lindqvistTL212 Jul 2026#69
h.amankwah, post #28: Note the site alongside the dose. If a local reaction appears three weeks later you will want to know where the previous four injections went. Scoping that to what I have actually seen rather than what I have read. Go to post

Taking post #66 at face value and following it one step further.

On completing a dose the community has more anecdote than the confidence in this thread implies, and I include my own contribution in that.

0 likes in reply to #28 16d
RR
r.restrepoTL214 Jul 2026 · edited#70
h.jansen, post #44: Completing a dose is a question about a distribution, not about a value, and treating it as a value is what produces the confident wrong answers. Go to post

Post #68 and I disagree about the size of the effect, not about the direction.

The practical version of completing a dose is three sentences long. The rigorous version is three pages and reaches the same conclusion with the conditions attached.

1 like in reply to #44 14d
AV
a.vestergaardTL215 Jul 2026#71
sa.vogel, post #35: Air bubbles in a subcutaneous injection: the honest risk assessment is low. Tiny air bubbles in subcutaneous tissue do not behave like an air embolism in a blood vessel. A few air bubbles are not a reason to restart the entire injection. I would rather say I do not know than round it up to an answer. Go to post

A new needle for each injection is not fussiness. A needle blunts on first use and a blunted needle is the reason the second injection hurts more than the first.

15 likes in reply to #35 12d
G
GEldridgeTL3Regular17 Jul 2026#72

Practical experience of completing a dose, offered as one case with the conditions stated, not as a general finding. Conditions first, because they are what make it interpretable.

5 likes 11d
AK
an.kirchnerTL219 Jul 2026#73

On post #71 — agreed on the reasoning, with one qualification.

Two sentences on completing a dose and then I will stop, because the rest is speculation and the thread is better without mine.

What is documented is narrow. What is inferred from it is broad. The gap between them is where every argument here lives.

0 likes 9d
GD
glossary_deskTL3Regular21 Jul 2026#74

Picking up post #71: that is the part I would want checked first.

If you have to inject at a different time of day than usual, that is a much smaller perturbation than it feels for a weekly compound with a week-long half-life.

This is the sort of thing that ought to be settled and apparently is not.

30 likes 7d
TD
t.demirTL223 Jul 2026#75
erratum_file, post #45: If you have to inject at a different time of day than usual, that is a much smaller perturbation than it feels for a weekly compound with a week-long half-life. Go to post

Completing a dose was covered in the wiki last year and the page has a review date on it, which is a better starting point than my memory of a thread.

21 likes in reply to #45 5d
GC
glossary_checkTL2Member25 Jul 2026#76

Post #75 answers the question as asked. The question underneath it is different.

Filing a mild objection to the consensus on completing a dose. Mild because I might be wrong; an objection because nobody has addressed the case that does not fit.

9 likes 3d
AF
a.friskTL227 Jul 2026 · edited#77

Worth separating two things that post #75 runs together.

A site rotation scheme that actually works: abdomen, outer thigh, back of arm, outer hip. Rotate through them in order, move a minimum 2 cm between consecutive sites, note the site with each dose. If a local reaction appears you have the history. If you rotate properly you will not get lipohypertrophy from overuse of one area.

Posted with less confidence than the sentence structure implies.

0 likes 1d

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