drug calculation

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Hi

Can someone please help me with the following drug calc. I am a bit stuck!!

Mrs. A was prescribed 800mg. of metronidazole tds. Pharmacy has supplied suspension with a dosage of 500mg/ml.

How much would you administer to this resident?

a) per dose- 800/500=1.6 (is this correct???)

b) in 24 hours- how do I calculate this one??? could someone please please help me out..

Thanks a million :)

TDS= three times a day

So, as above, you've figured out your 1.6 ml. And your problem tells you that you need to administer that three times in 24 hours.

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Rule of thumb. Always put the units of measure first. In this case it's asking for mLs.

1 ml/500 mg x 800 mg = 800/500 = 1.6 mL. As for the TDS or TID, I'm reading it as 800 mg or 1.6 mL times three and not in three divided doses.

Had my nursing 1 clinical instructor teach me that and I passed every math exam with 100.

Best of luck to you.

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TDS= three times a day

NEVER heard this one before!

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Specializes in Mental Health, Gerontology, Palliative.
Hey good to see :bugeyes: another Kiwi out here :yes:

yep but at Counties Manukau we mostly used TDS.. but I have heard about TID too!!

I got respect for any one working there. Thats one hell of a challenging catchment area. I'm in Christchurch, working elder care, but been doing temping at the local DHB

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Specializes in Mental Health, Gerontology, Palliative.
NEVER heard this one before!

We tend to use BD and TDS more commonly than BID and TID.

Mind you interrai being a north american invention uses BID and TID

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Specializes in Surgical, quality,management.

Check your route of administration. Flagal IV is 500mg, PO is 400mg.

Welcome from a colleague across the ditch!

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As others have already confirmed the 1.6ml is correct. The 2nd part of the question is a little confusing and I'm not sure what they are specifically looking for...is it how many doses in 24 hours or how many ml total will be given within that 24 hours? If the order is TDS or TID it just means you give every 8 hours for a total of 3 doses of 1.6ml in 24 hours, or a total of 4.8ml/24 hours.

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All this confusion about TID/TDS is why Joint Commission and ANA now recommends against the use of such acronyms.

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Hi

Can someone please help me with the following drug calc. I am a bit stuck!!

Mrs. A was prescribed 800mg. of metronidazole tds. Pharmacy has supplied suspension with a dosage of 500mg/ml.

How much would you administer to this resident?

a) per dose- 800/500=1.6 (is this correct???)

b) in 24 hours- how do I calculate this one??? could someone please please help me out..

Thanks a million :)

It helps me to line up the units

800mg 500mg

-----------------

Xml 1ml

800mg=500ml/X

x500 x500

------------------

1.6ml =x

then 3X for the three doses =4.8 ml or 2400mg whichever it asked for

does this make sense? hard to type it out in the box

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800 mg

________

500 mg/ml

1.6 ml x 3=

4.8 ml

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