Vancomycin infusion

[Asterix]

If i was giving a dose of 1.5g by IV

- I would reconstitute the 500mg vial with 10mls of water for injections
- Reconstitue 1g vial with 20mls of water for injections.

Would I then set the infusion of with the reconstitued 500mg and then wait and the nset of the reconstitued 1g after 500mg infusion is over??

Or do I add both the reconstitued powders to a 500ml bag of saline or glucose 5% and add it in?

[Asterix]

Also flow rate is 10mg/min

however guidance says 1.5g in 500ml over 180 mins

Is it not 150 mins?

[Nik]

In practice you would never go above 1g bd (although the BNF does say up to 1.5g bd). However, if for some reason 1.5g bd was indicated, giving them separately would take up too much nursing time. The max rate of admin for vanc to avoid red man syndrome is 10mg/min therefore technically the shortest time period is 150 mins. But why go for the shortest time and take the risk of them giving it over a quicker time ? 180 mins would be advised for practicality. Just like for a dose of 1g I would say not 100 mins but 120 mins.

[Asterix]

What about the 1g bd thing though nik, is that giving 500mg first, stopping infusion and then giving 500mg again???

Also in the bnf it says reconstitue each 500mg vial with 10mls of water and dilute with infusion fluid to a conc of up to 5mg/ml

So I want 750mg OD (for this ques sake, I know it would be bd). I reconstitue 500ml with 10mls, then do 500ml with 10mls again but only want 250ml so that will have 5mls of water right. The whole thing will be 15ml right?. So is that 750mg/15ml and I want to dilute to 5mg/ml. I have tried working it out by c1v1=c2v2 but i just dont get it

[crit care]

or you could use the 1g vials....

as for your question, its all ratios...you want a final conc of 5mg/ml and you have a 750mg dose, so 750 /5=150ml so you want to dilute it into at least 150ml. giving you a solution of 750mg/150ml, which is a 5mg/ml solution

[Asterix]

or you could use the 1g vials....

as for your question, its all ratios...you want a final conc of 5mg/ml and you have a 750mg dose, so 750 /5=150ml so you want to dilute it into at least 150ml. giving you a solution of 750mg/150ml, which is a 5mg/ml solution

so you use a 150ml bag or anything bigger yeah?

[Asterix]

i thought the 750 would be in 15ml water for injection no? as 500mg is reconstitued with 10ml water for injection and so 250mg more would be in 5ml water for injection making 15ml total water

[crit care]

a 150ml bag doesn't exist, but you can use anything bigger than 150ml as the concentration is going to beaker than 5mg/ml.

yeah the 750mg is in 15ml solution, but you need to dilute it as otherwise you have a concnetration of 50mg/ml...not quite sure what you mean

[Asterix]

yeah 150ml bag isnt available so would you go for 200ml bag. But if you used the 250ml bag, wouldn't you be diluting in too much??

[crit care]

200ml bag doesn't exist.....there is no problem in diluting it too much, as long as you don't exceed 5mg/ml...but can go to a max conc of 10mg/ml but i wouldn't worry about that!!

you would want to give it in an appropriate volume to the patient and what is easier for the nurses..pointless getting them to remove a volume from the bag and then adding the vancomycin...creates more work and room for errors..adding a 1g dose to 250ml is reasonable, providing the patient can tolerate 250ml and isn't fluid restricted or in pulmonary oedema