I need help on a math problem!! Not making sense to me

Write it out:

Convert grains to milligrams first. 5 Grains = 325 Milligrams.

Milligrams to Grains conversion

(This link can help you with some conversions.)

So, now we write the problem out. I am doing it the long way, to prevent error.

Remember that the 1st and 3rd units of measurement in this equation have to match.

300 m.g. : X tabs :: 325 m.g. : 1 tab

(So now we drop the symbols. Remember, what ever you do to one side of the equation, you must do to the other. We are solving for X.)

300 : X :: 325 : 1.

Multiply your means first, then your extremes:

X times 325 = 325X Underline that, and to the right of that, multiply 300 X 1

So 325X = 300. Now divide both numbers by 325, because that is the number next to X and we are solving for X.

We need to get X by itself.

After you do that, divide the 300 by 325 = 0.93 tabs. So unless the Pharmacy can chop it up for you, you will end up giving a whole tab. Hope I haven't confused you further!

I had an order for Valium 4 mg. po, and the PYXIS only offered me a 5 mg. tab. I called the pharmacy to ask what I should do, and I was told that this was a nursing issue. They didn't think it was funny when I offered to just lick the tab until I had take off 1 mg. In the end, I think I called the MD to change the order, but why did pharmacy even enter it when they couldn't deliver it?

They follow orders. But really, that's a question that you should be asking them. There are times when physicians order meds that aren't always available in some pharmacies. But then usually the Pharmacist lets the dr. know.

Well 5 grain is equal to 323.995mg. That's where I am stuck. You can't give a fraction of a tablet lol

Indeed you CAN give a fraction of a tablet. We cut tablets all the time in pediatrics. You can't give this particular fraction which is 0.93 tablet so you'd end up giving the whole thing. In the US, Aspirin is available in 81 mg and 325 mg tablets. In other countries, it is available in 75 mg and 300 mg tablets. Perhaps the ordering MD is from a country where the typical adult dose is 300 mg. If so, have the Pharmacy call him and explain that in the US, the typical adult dose is 325 mg and ask him to change the order.

When I learned dosage calculations, we learned about grains and 1 grain = 60 or 65 mg. When I saw that I just really really hoped it would never appear on an exam - WHICH ONE WOULD I USE?!?! - LOL. But I think over my whole time in school maybe 1 instructor gave an exam with 1 question using grains and I have never encountered them ever before! Like soutthpaw said - Its old and not a very accurate measurement!

I just think instructors could be coming up with much better, more REAL WORLD examples for students to learn dosage calculations with!

If I recall correctly from the dark ages, didn't we used to give aminophylline as gr VII 1/2? Used that squiggle ss symbol with the dots over the ss.

Morphine was that way too.

If I recall correctly from the dark ages, didn't we used to give aminophylline as gr VII 1/2? Used that squiggle ss symbol with the dots over the ss.

Morphine was that way too.

I bet you remember Butazolidin Alka and APC c Cod.

To bj - yes, I do!

And those little round disks that would dispense narcs from the wheel. (Like some old birth control pill dispensers.)

Ooh, ooh, I just thought of another. At my first LPN job, we had a hospice patient who had tincture of opium ordered in minums. It was a greenish-black liquid.

tincture of belladonna?

I am an 'oldie'. I still forgot at times and wrote "Tylenol gr X" as easy as I would write my name.

Always convert to what is available so in this case, you would convert the 300 mg to grains.

(you do know how to covert, right??)

1 grain=60 mg

Are you familiar with the dimensional analysis way of doing dosage calculations??

It would be solved like this:

300mg/1 x 1 gr/60mg x 1 tab/5 grains (write these as fractions on your paper. Cross out your "look-a-likes", meaning both mg and grains, so that you can see that you're left with tabs, which is what the calculation asks for) which would give you 300/300, which is 1 tablet