Order: Ampicillin 750mg im q6hSupply: 1 gram vial of ampicillinDirections: add 2.4 ml sterile water to yield 2.5 ml of soltuion750 mg x 2.5 ml = 18751 gram = 1000 mgD/H = 1875/1000 = 1.9 ml.Order: Nafcillin 750 mg IM qidSupply: Nafcillin 2 gram vialDirections: add 6.8 ml sterile water for total of 8 ml of solution.750 mg x 8 ml = 60002 gram = 2000 mgD/H= 6000/2000 = 3 ml. 0 Likes

Guest Add your Credentials, Experience, etc. Aug 11, 2014 Order: Ampicillin 750mg im q6h Supply: 1 gram vial of ampicillinDirections: add 2.4 ml sterile water to yield 2.5 ml of soltuion750 mg x 2.5 ml = 1875 ... Note: You cannot arbitrarily drop units... they have meaning and are treated algebraically just as are numbers and variables... This should say: 1875 mg ml1 gram = 1000 mgD/H = 1875/1000 = 1.9 ml. Same deal... you pulled "ml" out of thin air... rather, it should be: "1875 mg ml / 1000 mg = 1.9 ml"Order: Nafcillin 750 mg IM qidSupply: Nafcillin 2 gram vialDirections: add 6.8 ml sterile water for total of 8 ml of solution.750 mg x 8 ml = 60002 gram = 2000 mgD/H= 6000/2000 = 3 ml. Same deal... disappearing and reappearing units... gonna bite you in the butt...Your numbers appear correct (though I didn't check the math) but your intermittent use of units is (a) improper, and (b) a recipe for disaster. 0 Likes

pmabraham, BSN, RN Specializes in Hospice, Palliative Care. Has 3 years experience. Aug 11, 2014 Good day, Mursely:I appreciate you and others who are posting dosage calculation problems as it gives all of us practice; thank you. Your math looks good, though a lot of times I see the formula method as D/H * Q. I don't know if any of your instructors would be like the nuns I had in middle school with rulers smacking knuckles, but I can envision that if you get picky proctors for a test.Thank you. Edited Aug 11, 2014 by pmabraham 0 Likes

smf0903 Aug 23, 2014 Order: Ampicillin 750mg im q6hSupply: 1 gram vial of ampicillinDirections: add 2.4 ml sterile water to yield 2.5 ml of soltuion750 mg x 2.5 ml = 18751 gram = 1000 mgD/H = 1875/1000 = 1.9 ml.Order: Nafcillin 750 mg IM qidSupply: Nafcillin 2 gram vialDirections: add 6.8 ml sterile water for total of 8 ml of solution.750 mg x 8 ml = 60002 gram = 2000 mgD/H= 6000/2000 = 3 ml.I agree totally with music in my heart's post to you. You need to take care to keep track of units and such:2.5mL/1000mg * 750mg = 1.875mL =1.9mL8mL/2000mg * 750mg = 3mL 0 Likes

Kuriin, BSN, RN Specializes in Emergency. Has 4 years experience. Aug 23, 2014 Good day, Mursely:I appreciate you and others who are posting dosage calculation problems as it gives all of us practice; thank you. Your math looks good, though a lot of times I see the formula method as D/H * Q. I don't know if any of your instructors would be like the nuns I had in middle school with rulers smacking knuckles, but I can envision that if you get picky proctors for a test.Thank you.I'm confused, what is wrong with the above's formula? I've personally always read it as Want/Have*Vehicle.Just trying to figure out what would the pickiness be about. 0 Likes

pmabraham, BSN, RN Specializes in Hospice, Palliative Care. Has 3 years experience. Aug 23, 2014 Good day, Kuriin:Re-read Mursely's post to see if the formula was used in form or not, then re-read my post.Thank you. 0 Likes

Kuriin, BSN, RN Specializes in Emergency. Has 4 years experience. Aug 23, 2014 Whoooops. Didn't realize he/she didn't use the W/H*V formula. Whatever works. :) 0 Likes

loveofrn, BSN, RN Specializes in MICU. Has 3 years experience. Aug 23, 2014 I still dont know how to use the above formula. The method that works for me is to know what the problem is asking and then solve it in dimensional analysis or in ratio. I think before jumping to any formula, we need to understand the question, then dosage math would be easier than abc 0 Likes

THELIVINGWORST, ASN, RN Specializes in Public Health. Has 4 years experience. Aug 23, 2014 Dimensional analysis always works so you don't get confused. 0 Likes

loveofrn, BSN, RN Specializes in MICU. Has 3 years experience. Aug 23, 2014 Dimensional analysis always works so you don't get confused.Not everytime!!! I learned that the hard way 0 Likes

NCH, RN Aug 23, 2014 Your method confused me, but I came up with the same answers, so it looks good to me. 0 Likes

loveofrn, BSN, RN Specializes in MICU. Has 3 years experience. Aug 23, 2014 Your method confused me, but I came up with the same answers, so it looks good to me.Whose method? 0 Likes

loveofrn, BSN, RN Specializes in MICU. Has 3 years experience. Aug 23, 2014 The op'sThere are many methods. What matters most is understanding the question, then you can apply the method that works for you. I use DA most of the time. 0 Likes