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Reserpine Liquid 0.1 m g per m l Disp: 60 m l Sig: 0.01 m g per kg per dose one dose twice a day
Remember: On NAPLEX, your answer m ay be expressed in a different set of units other than the ones you used to work the problem. For exam ple, a problem that gives an answer of 100 m g m ay be expressed as 0.1 gram. Sim ilarly, 0.5 m g could be expressed as 500 m cg or 0.0005 gram s.
Use the inform ation provided for questions 1 through 3. You receive an order for 500 m g of aminophylline in norm al saline in a total volume of 250 ml. The patient weighs 132 pounds. The aminophylline is to be administered at a dose of 0.3 mg per kg per hour. Aminophylline Injection is supplied in vials with 25 mg per ml. The IV set you will use delivers 60 drops per ml.
- How many m illigrams of theophylline will the patient receive each hour?
- How many hours will the 250 m l last if administered at the correct dose?
- W hat will be the flow rate, in drops per minute, to administer the dose ordered?
- A dose of 120 mg of gentamicin is administered IV. After 10 minutes, a blood sam ple is assayed for gentamicin content. The result is 8 mcg per ml. W hat is the volume of distribution for gentamicin?
Use the prescription shown for questions 5 through 8. You have tablets that contain 0.25 mg of reserpine per tablet. You can m ix ground up reserpine tablets in cherry syrup to make a liquid that will be stable for at least 3 months. The patient is a child that weighs 22 pounds.
- How many reserpine tablets will be needed to compound the prescription?
- W hat volume (ml) will be in each dose?
- How long will this prescription last at the dose ordered?
- If reserpine tablets cost $20.00 per 100 tablets, what will be the cost of the tablets used?
Questions 9 and 10. You need to prepare 30 grams of 0.25% triamcinolone in Cold Cream. Triamcinolone is available in a suspension of 40 mg per ml that has a specific gravity of 1.0.
- How many ml of the triamcinolone solution will be needed?
- How many grams of the Cold Cream will be needed?
Question 11 thru 13. You are to mix this IV using the materials shown. You must ADD the volumes of the dextrose and NaCl to the 1000 ml of Sterile W ater.
- How many ml of the Sodium Chloride Injection, 23.4% , will you add to the sterile water?
- How many m l of the Dextrose 70% in W ater Injection will you add to the sterile water?
- After all of the ingredients are mixed, what will be the flow rate in milliliters per hour?
Sterile Water for Injection 1000 ml Dextrose 10 % Sodium chloride 60 mEq Adm inister over 24 hours
Sterile W ater for Injection, 1000 ml Sod Chloride Inj, 23.4% (MW = 58.5) Dextrose 70% in W ater Injection
Provide the correct conversion factor for each instance below:
- 1 grain = milligrams
- 1 avoirdupois pound = grams
- 1 fluid ounce = milliliters
- 1 US gallon = fluid ounces
- 1 US pint = m illiliters
- Digoxin Injection is supplied in am pules of 500 m cg per 2 m l. W hat quantity, in mL, must a nurse administer to provide a dose of 0.2 mg?
- Gentamicin Injection is supplied in a concentration of 80 mg per 2 m l vial. How many m illiliters are needed to give a single dose of 4 mg per kg to a patient weighing 165 pounds?
- You have Sodium Phenobarbital Injection, 13%. How many m l will be needed to obtain 2 grains?
- Concentrated Acetic Acid is supplied at a concentration of 90% weight/weight and has a specific gravity of 1.11. W hat volume is needed to obtain enough acetic acid to prepare 60 mls of Acetic Acid Solution, 5% (e.g., vinegar)?
Use the prescription to the left for questions 23 and 24.
- How many milligrams of codeine will be needed to compound the prescription?
- W hat will be the total final weight, in grains, of ingredients for one capsule?
- A patient is to prepare one liter of a 1:5000 potassium perm anganate (KM nO ) solution as a foot 4 soak. You have a stock solution of KMnO , 5%. How many milliliters of the stock solution m ust be 4 used to prepare one liter of the foot soak?
Inform ation For Problem s 26 and 27. Your patient is receiving lithium carbonate (Li CO ) capsules but 2 3 needs to change to a liquid form (lithium citrate; Li C H O ). Molecular w eights: lithium = 7, carbon = 3 6 5 7 12, hydrogen = 1, oxygen = 16
- If the patient’s dose of lithium carbonate was 300 mg three times a day, how many m illimoles of lithium did the patient receive in a day?
- Lithium citrate syrup is available as 300 mg of lithium citrate per 5 ml of syrup. How many milliliters of syrup will be required per day to provide the dose calculated in No. 26?
- You have a vial that contains 5 gms of drug and the chart to the right for mixing the drug for use. Nurses want to m ix the vial so that it comes out with 200 m g per m l and ask you how much diluent they should add to make that concentration.
Aspirin 300 m g Caffeine 30 m g Codeine 15 m g DTD 15 caps SIG: i cap q 4 hrs PRN pain
Diluent Added Concentration Resulting 9.6 m l 500 m g per m l 19.6 m l 250 m g per m l 49.6 m l 100 m g per m l
Use the prescription shown for questions 40 and 41.
- Morphine Sulfate is available in 15 mg tablets. How many tablets would provide the amount of m orphine needed for this prescription?
- If each morphine tablet weighed a total of 100 mg, what would be the weight of material in one capsule?
- A drug product costs $62.20 an avoirdupois ounce. W hat will be the cost of the 60 mg of drug you need for a prescription?
- A patient is to receive IV theophylline 24 mg every hour. If am inophylline is 80% theophylline, how much aminophylline must the pharmacist use to prepare a 24 hr supply?
- Aminophylline Injection is supplied as 25 mg per ml. W hat volume of Aminophylline Injection will the pharm acist need to obtain the dose in Number 43 above?
- A drug product has 0.05% active drug. If the dose is one-half (½) teaspoonful four times a day for ten days. How many milligrams will be consumed in total?
- You have a stock drug solution that contains 10% active drug. W hat volume of this stock solution will you use to prepare 120 ml of a 1:1000 solution?
- A formula calls for using 0.01% of hydrochloric acid in a formula for 1000 ml of a topical liquid. HCl has a specific gravity of 1.2 and is supplied as a 40% weight/weight solution. How many m l of hydrochloric acid are needed to prepare the 1000 ml?
- Amikacin Injection is supplied as 500 mg in 2 ml. Mr. Johns weighs 198 lbs and is to receive a dose of 15 mg per kg. How many m illiliters will be needed for the dose?
- Calcium Chloride Dihydrate Injection is supplied as a 10% solution in water. How many m illiosmoles are present in a single 10 ml vial? Ca = 40, Cl = 35.5, H = 1, O = 16
- Sodium Bicarbonate Injection is an 8.4% solution. How many milliequialents of sodium are in a single vial of 50 ml? Na = 23, C = 12, O = 16, H = 1
- Lidocaine Injection for cardiac use is a 4% solution. If the dose is 2 mg per minute, how long will a 500 ml bag run?
- I have 10 ml of a solution that contains one gram per 5 ml. How many ml of water must I add to the 10 ml to make a solution that is 1:5000 in strength?
Inform ation for questions 53 and 54 is contained in the box to the left. This formulation is for 24 hours of a total parenteral nutrition (TPN) formulation. Dextrose provides 3.4 calories (or kilocalories or kcals) per gram and Am ino Acids provide 4 calories per gram. The electrolytes and vitamins do not provide any calories. (Fat provides 9 calories per gram.)
Morphine Sulfate 7.5 m g Acetam inophen 325 m g DTD: XX caps Sig: one cap q 4 hrs prn pain
Total Parenteral Nutrition Formula Dextrose Injection, 50% 1000 ml Amino Acids, 10% 400 ml Electrolytes / Vitamins 200 ml Sterile W ater 800 ml
Indom ethacin 0.05% Boric Acid qs W ater qs ad 15 m l
Total W BC Count Bands Segs Basophils Eosinophils Lymphocytes M onocytes
14,000/m m 3 5 65 1 2 24 3
- How many calories, from all sources, will the patient receive in 24 hours?
- The IV set will deliver 10 drops per ml. W hat will be the flow rate, in drops per m inute, to adm inister the formula above over 24 hours?
- The proper concentration of benzalkonium to prevent bacterial contamination in an eye drop is 1:750. You have a stock solution of 17% benzalkonium chloride and a dropper that delivers 50 drops per m l. How many drops will you need for a 30 ml bottle of eye drops?
- A patient has been receiving oral Aminophylline Tablets. Aminophylline is 80% theophylline. The doctor wants to change giving oral theophylline. If the patient has been receiving 500 mg of aminophylline, and theophylline is available in tablets of 100 mg. How many tablets will the patient need per dose? (NOTE: Bioavailability will be the same for both.)
- Dimethyl Sulfoxide Liquid is supplied as a 50% weight / weight solution with a specific gravity of 1.40. W hat is the percent weight / volum e of liquid dimethyl sulfoxide?
The prescription to the right has inform ation for questions 58, 59 and 60.
- Boric Acid can be used as a preservative in ophthalmic solutions. It can also be used to replace NaCl when making a product isotonic. W hat quantity of boric acid will be needed to make the eye drop shown isotonic? E values are boric acid = 0.52, indomethacin = 0.
- You have boric acid in a saturated solution that is 5.5% boric acid. W hat volume of this solution will you need to use to obtain the needed amount of boric acid?
- Indomethacin is available in an injection of 1 mg powder for solution per vial. How many vials will you need to obtain the needed amount of indomethacin?
Use the white blood cell differential count shown to answer questions 61, 62 and 63.
- This patient is most likely to have what type of infection – bacterial, viral, fungal? I. Bacterial II. Viral III. Fungal A. I only B. III only C. I and II only D. II and III only E. I, II and III only
- W hat will be the absolute neutrophil count for a patient with the W BC result shown above?
- W hat will be the absolute granulocyte count for a patient with the W BC result shown above?
Atropine Sulfate 0.4 mg Morphine Sulfate 5 mg Acetaminophen 325 mg DTD: 20 caps SIG: 1-2 caps q 4 hrs prn Dr Anodyne
- You need a 1:5000 solution of benzalkonium chloride as a preservative. You have 20 ml of a 1: solution in stock. How much of the 1:5000 solution can you prepare by using all 20 ml of the 1: solution?
- You need a 1:750 solution of Zephiran Chloride to disinfect the pharmacy counters. Zephiran is available as a 17% concentrated solution. How much Zephiran concentrate will you mix with enough water to make one gallon of the 1:750 solution you need?
- An IV solution containing potassium chloride is being administered at a rate of 30 drops per m inute using IV tubing that delivers 15 drops per mL. At the end of 8 hours, the patient has received 30 mEq of potassium chloride. W hat was the initial concentration of potassium chloride in the IV fluid? K = 39, Cl = 36
- You told your assistant to make a 3 percent m orphine solution but something got misunderstood and the result is 80 mL of a 20 percent solution. How much water must you add to the 80 m L to reduce the concentration to 3 percent?
Use the inform ation in the box provided to answer questions 79 through 81.
- Approximately how much atropine sulfate, IN GRAINS, will you need to use to compound the prescription?
- How many grams of acetaminophen will you need for the 20 capsules?
- W hat will be the total weight of ingredients, in milligrams, to prepare the entire quantity?
Questions 82, 83 and 84 use the same inform ation to dem onstrate the differences, and sim ilarities, between m illim oles, m illiosm oles and m illiequivalents.
- Lactated Ringer’s Injection contains 20 mg of calcium chloride dihydrate per 100 ml of IV fluid. How many m illiMoles of calcium are present in one liter of Lactated Ringer’s Injection? Molecular weights: Ca = 40, Cl = 35.5, H = 1, O = 16
- Lactated Ringer’s Injection contains 20 mg of calcium chloride dihydrate per 100 ml of IV fluid. How many milliOsmoles of calcium chloride are present in one liter of Lactated Ringer’s Injection? Molecular weights: Ca = 40, Cl = 35.5, H = 1, O = 16
- Lactated Ringer’s Injection contains 20 mg of calcium chloride dihydrate per 100 ml of IV fluid. How many mEq of calcium are present in one liter of Lactated Ringer’s Injection? Molecular weights: Ca = 40, Cl = 35.5, H = 1, O = 16
- You dilute 1 ml of Fungizone Injection (50 mg per 10 ml) to one liter. The concentration in the diluted solution will be (express as N:XXXX, such as 1:1000)
- Neupogen Injection is supplied at a concentration of 0.48 mg/1.6 ml. Your patient (weighs 132 pounds) and is to receive a dose of 5 mcg/kg/day. W hat volume of Neupogen Injection is required for this dose?
- The parents of a child cannot read or speak English and a pediatrician knows the mother is going to give the child one teaspoonful of medication per dose no matter what dose is ordered. The pediatrician wants you to add enough water to make Biaxin Oral Suspension to a concentration of 150 m g per 5 mL. You have a container of Biaxin powder for oral suspension that says that addition of 55 mL of water will result in a final volume of 100 mL at a concentration of 250 mg per 5 m L. How much water must you use to change the final concentration of this container to 150 mg per 5 mL?
Inform ation for questions 88 through 91. A patient is receiving Dextrose 5% in 0.45% Sodium Chloride Injection and 40 mEq of potassium chloride in a total volume of 1000 mL through an IV set that delivers 15 drops per m L. The IV fluid has been running at a rate of 12 drops per minute for 15 hours. Molec W eights: Dextrose = 180, Na = 23, K = 39, Cl = 35.
- How many mEq of potassium chloride have been adm inistered so far? K = 39; Cl = 35.5; Na = 23; Dextrose = 180
- How many grams of KCl have been administered over the 15 hour period?
- How many millimoles of KCl have been administered over the 15 hour period?
- W hat is the total osmolarity of the IV fluid being adm inistered? Express your answer as m illiosmoles, rounded to the nearest whole num ber, per 1000 mL.
- A formulation for an oral liquid of sum atriptan succinate (Im itrex – for migraine headaches) indicates that the final product should have a pH between 4.2 and 5.3. W hat pH would represent the middle of this range?
- A table of pKa values gives 4.75 as the pKa for acetic acid. Use the Henderson-Hasselbach Equation to calculate the relative molar ratios of sodium acetate and acetic acid required to prepare a pH 4. buffer.
- Determ ine the actual quantities, in grams, for a buffer that uses one m ole of sodium acetate (NaC H O ) and the corresponding amount of acetic acid (C H O ). Molecular W eights: Na = 23, C 2 3 2 2 4 2 = 12, H = 1, O = 16
Inform ation for questions 95 and 96. A physician wants to put 10 m Eq of calcium into a 500 m l bag of Normal Saline Solution and adm inister the calcium at a rate of 0.5 mEq per hour. You have Calcium Chloride Dihydrate, 10% Injection in 10 mL vials. Ca = 40, Cl = 35.5, H = 1, O = 16
- How many mLs of this injection must you add to the bag of IV fluid to m ake the desired product?
- You have an IV set that delivers 12 drops per mL. At what flow rate (drops per minute) will the IV fluid be administered to give the desired dose?
Inform ation for questions 97 through 99. Mr Shirrah is very ill and needs antibiotic therapy for an infection. The microbiology lab reports that the infecting agent will require a higher than normal blood level to be effective. The attending physician asks you to determine exactly how often each dose of the antibiotic should be administered to keep the blood level at, or above, the determined minimum inhibitory concentration (MIC).
- W hat type of catheter will be inserted into the patient’s bladder and used for administration of the amphotericin B bladder irrigation? A. Swan-Ganz catheter B. PICC catheter C. Foley catheter D. Central catheter E. Robinson catheter
Inform ation for questions 108, 109 and 110. A patient (weight, 176 pounds) in cardiology is receiving a heparin drip, currently running at 15 units per kilogram per hour. The concentration of heparin in the IV drip is 10,000 units per 100 mL and the IV set delivers 15 drops per mL. The most recent partial thromboplastin time (PTT) indicates that the patient is being under dosed and that the heparin rate should be increased by 20% according to the hospital’s weight based heparin protocol. Answer the following questions:
- W hat will be the new dosage in units per kilogram per hour?
- W hat will be the new flow rate in drops per m inute?
- Once the heparin drip was stopped, the physician wanted to change to a subcutaneous agent for further anticoagulation. A possible drug for this purpose would be A. W arfarin B. Alteplase D. Daltaparin C. Argatroban E. Lepirudin
Inform ation for questions 111 through 117 is included in the box to the right. A physician has found a new formula for an IV fluid to be administered after surgery that can be described as “TPN Lite”. The formulation is shown in the box to the right. Use the formula provided to answer the following questions:
- How many mLs of Dextrose Injection, 700 mg/m L, will be needed to prepare one liter of the formula?
- How many mLs of Am ino Acids Injection, 10% will be needed to prepare one liter of the formula?
- How many m Ls of Sodium Chloride Injection, 4 m Eq per mL, will be needed to prepare one liter of the formula? Na = 23; Cl = 35.
- How many m Ls of Potassium Chloride Injection, 2 m Eq/ml, will be needed to prepare one liter of the formula? K = 39; Cl = 35.
- How many mL of water will be required to prepare one liter of the formula?
- The first patient to receive this IV fluid had GI tract surgery and needs to be NPO for 5 days. The patient weighs 85 kilograms. How many calories from the dextrose and the amino acids will the patient receive in 24 hours?
- The IV set used to administer this solution delivers 12 drops per mL. W hat will be the flow rate to administer the solution at the dose ordered for this patient?
- Don Smith is a 35 year old male who has been diagnosed with AIDS. Mr. Smith is 5 feet, 8 inches tall and weighs 180 pounds. Mr. Smith’s physician wants to use Epivir and knows the drug m ust have its dose adjusted based on a patient’s renal function. Mr. Smith’s serum creatinine is 2. mg/dL and has held at that sam e level for 5 days. Calculate Mr. Smith’s creatinine clearance.
Dextrose, 15% Am ino Acids, 4% Sod Chloride, 0.75% Pot Chloride, 0.2% MVI-12, 10 mL Sterile W ater qs ad 1000 mls Flow Rate: 1 mL per kg per hour
- The dosing literature for Epivir has the following information concerning use in renal failure. W hat is the appropriate dose for Mr. McClure?
Creatine Clearance Initial Dose Maintenance Dose
< 5 ml/min 50 mg 25 mg once daily
5 – 14 ml/min 150 mg 50 mg once daily
15 – 29 ml/min 150 mg 100 mg once daily
30 – 49 ml/min 150 mg 150 mg once daily
- Mr Sm ith is unable to take his Epivir and will have a NG tube inserted to make oral drug administration m ore practical. If the physician prescribes Epivir Oral Solution, 10 mg per ml, what will be the actual volume administered to Mr Smith?
And Now – The Answers
- 132 lbs (div by) 2.2 lbs/kg = 60 kg 60 kg (x) 0.3 mg Aminophylline/kg = 18 mg/hr
Question calls for theophylline dose per hour 18 mg Amin (x) 0.8 = 14.4 m g Theo
NAPLEX will expect you to know that Aminophylline (MW = 420) is theophylline ethylenediamine and that the amount of theophylline (MW = 180) in aminophylline is 80%. The ethylenediamine is the other 20% of the total molecular weight. There are two molecules of theophylline per molecule of ethylene diam ine in am inophylline.
- 500 m g Amino (div by) 18 mg/hr = 27.77 hrs
- 250 ml fluid (x) 60 drops/ml = 15000 drops 27.77 hrs (x) 60 mins/hr = 1666 mins
15000 drops (div by) 1666 mins = 9 drops per minute
ALTERNATIVELY: 250 ml (div by) 27.77 hrs = 9 ml per hour
9 ml/hr (x) 60 drops/ml = 540 drops per hour (div by) 60 mins/hr = 9 drops/min
NOTE: with a pediatric IV set (delivers 60 drops per ml) ml/hour and drops/min are the same number.
- MW of NaCl = 58.5, so 58.5 mg = 1 millimole
Na +is monovalent (one charge), thus 58.5 mg (div by) 1 = 58.5 mg = 1 milliequivalent
60 mEq (x) 58.5 mg/mEq = 3510 mg needed 23.4 % = 234 mg per ml
3510 mg (div by) 234 m g/ml = 15 ml required
Another way to work No. 11 234 mg = 4 mEq per ml 58.5 mg/mEq
60 mEq (div by) 4 m Eq/ml = 15 ml required
X ml = 1015 ml = 169.17 ml
- Best solved 70% 10 parts 10 parts 60 parts by using 10% alligation 0% 60 parts = 1015 ml (1015 ml includes the NaCl added) 70 parts (will be total volume after all additions = 1184.17 ml)
- 1000.00 ml of sterile water 1184.17 ml (div by) 24 hrs = 49.34 ml/hr 169.17 ml of dextrose 70% 15.00 ml of NaCl 23.4% W ould really run at 49 or 50 ml per hour. 1184.17 ml Total Volum e NAPLEX answers are multiple choice and would include 49 or 50, but not both.
- 1 grain = 64.8 m g exactly 65 mg is usable, 60 mg only in some circumstances
- 1 avoirdupois pound (one we all know) = 454 gram s (exact is 453.6 grams)
- 1 fluid ounce = 29.57 milliliters exactly 30 ml routinely used
- 1 US gallon = 128 fluid ounces (also 3785 ml, 4 quarts, 8 pints)
- I US pint = 473 mls 480 m ls – 16 fluid ounces (x) 30 ml/ounce) – is often used
- 0.2 mg = 200 m icrograms Use either one X ml = 2 m l = 0.8 ml needed 500 m cg = 0.5 milligrams 200 m cg 500 m cg
- 165 pounds (div by) 2.2 lbs/kg = 75 kg X ml = 2 m l = 7.5 ml needed 75 kg (x) 4 mg/kg = 300 mg needed 300 mg 80 mg
- 1 grain = 65 mg (x) 2 = 130 mg needed 13% = 130 mg per ml; so you need 1 ml
- % weight/weight (x) specific gravity = % weight/volume
90% wt/wt (x) 1.11 (SpGr) = 99.9 % wt/vol -or- 100%
% = grams per 100 ml, so 100% = 100 grams per 100 ml -or- 1 gram per ml
60 ml (x) 0.05 (= 5% ) = 3 grams needed; if concentration is 1 gm/ml, then need 3 ml
- DTD means the formula is for one capsule 15 mg/cap (x) 15 caps = 225 m g needed
(MFT was once used to mean the formula was for 15 caps but is now routinely used to simply indicate to “mix and make” capsules.)
MPJE Law Note on No. 23: You probably would use C-II codeine to prepare the product, but after mixing the codeine with other drugs you would now have a C-III product (equivalent to Tylenol No. 2 tablets.) BUT, If you simply dissolve codeine in water, cherry syrup or some other diluent with no active ingredients, then the product would remain a C-II because codeine only converts to a C- III or C-V when mixed with other active ingredients that limit abuse of the codeine.
- 300 mg + 30 mg + 15 mg = 345 mg per capsule
345 mg (div by) 65 mg per grain = 5.3 grains per capsule
- 1: 5000 means 1 gram in 5000 ml X mg = 1000 mg = 200 mg for 1000 ml 1 gram = 1000 mg, thus we would 1000 ml 5000 ml have 1000 mg in 5000 ml, but we are only m aking one liter (1000 ml) 5% = 50 mg/ml 200 m g = 4 m l needed 50 mg/ml
- MW of Li (^) (two)carbonate = 74 Thus, 74 mg of Li Carb = 2 millimoles of lithium
300 m g (x) 3 doses/day = 900 m g per day X mMoles = 2 m Moles = 24.3 m Moles 900 mg 74 mg per day
- MW of Li (^) (three)citrate = 210 Thus, 210 mg of Li citrate = 3 millimoles of lithium
X mg = 210 mg = 1701 mg of Li citrate X ml = 5 ml = 28.35 ml 24.3 mMoles 3 mMoles needed daily 1701 mg 300 mg per day
(NAPLEX could ask for a specific dose. In this case 10 ml TID would be a good dose.)
- At a concentration of 500 mg per ml, and 5 grams of drug, there would be a total volume of 10 ml. But only 9.6 m l of diluent was added, so the powder contributed 0.4 m l to the final volume. Similarly, at 250 mg/ml, there would be 20 ml of volume and at 100 mg/ml there would be 50 ml of volume. In each case the am ount of diluent added was 0.4 m l less than the final volume. Therefore, the powder will contribute 0.4 m l to the volume.
5 grams = 5000 mg 5000 mg (div by) 200 mg/ml = 25 ml of total volume
25 ml (minus) 0.4 ml (the powder volume) = 24.6 ml of diluent to add to make 200 mg/ml
- Can be 1% 0.1 parts X grams = 30 grams = 3 grams of 1% done by 0.1% 0.1 parts 1 part hydrocortisone alligation 0% 0.9 parts 1 part = 30 grams 30 gm s (m inus) 3 gm s = 27 grams of cold cream needed
- DTD means formula is for one capsule 0.3 mg/cap (x) 20 caps = 6 m g needed
NOTE: W hen unsure about is the formula for one capsule or for several capsules, just go by the dose per capsule. In this case, 300 mg is the usual dose of acetaminophen. If you divided that by 20, you would get a dose of 20 mg for the acetaminophen and that is just too low.
- 6 m g (div by) 60 mg per grain = 1/10th of a grain (6 m g was determined in No. 37, above)
X tabs = 1 tab = 1/10 (x) 1 Invert and 1 (X) 150 = 15 tabs 1/10th grain 1/150th grain 1/150 multiply 10 1
NOTE: Hyoscine HBr is a potent alkaloid and, as such, the grain to m g equivalent is reduced to 60 mg per grain to provide a safety factor when administering the drug. This same concept is the usual reason for drug products where 60 mg = 1 grain. Again, with NAPLEX being m ultiple choice, you can get the answer they want. NAPLEX would likely set up the answer to be based on the 64. mg grain.
- 100% = 50 (Accuracy Factor) 50 (x) 5 mg sensitivity = 250 m g least amount that 2% can be weighed with 2% accuracy
- DTD = 20 caps (x) 7.5 mg/cap = 150 m g needed (div by) 15 mg/tab = 10 tabs needed
- 10 tabs (x) 100 mg/tab = 1000 mg for the morphine 1000 mg 325 mg (x) 20 caps = 6500 mg for the acetaminophen 6500 mg 7500 mg (div by) 20 = 375 mg per capsule
- 1 avoirdupois ounce = 28.35 grams = 28,350 m g $ X = $ 62.20 = $ 0.13 (13 cents) 60 mg 28,350 mg
- 24 mg/hr (x) 24 hrs = 576 mg theophylline
576 m g (div by) 0.8 = 720 m g of aminophylline needed
- X ml = 1 ml = 28.8 ml 720 mg 25 mg
- 0.05% = 0.5 mg per ml one teaspoonful = 5 ml, so one-half teaspoonful = 2.5 ml
2.5 ml/dose (x) 0.5 mg/ml = 1.25 mg per dose (x) 4 doses/day (x) 10 days = 50 mg
- 1:1000 means 1 gram in 1000 ml -or- 1000 mg in 1000 ml -or- 1 mg per 1 ml
120 ml are to be prepared, so you will need 120 mg
10% = 100 m g per ml in stock solution 120 m g (div by) 100 m g/ml = 1.2 ml needed
- 0.01% = 0.1 mg/ml (x) 1000 ml = 100 m g HCl needed
40% wt/wt (x) 1.2 sp grav = 48% wt/vol 48% = 480 mg per ml
100 m g (div by) 480 m g/ml = 0.21 m l HCl needed
- 198 lbs (div by) 2.2 lbs/kg = 90 kg (x) 15 mg/kg = 1350 mg needed
500 mg in 2 ml = 250 mg/ml 1350 mg (div by) 250 mg/ml = 5.4 ml
- CaCl 2 * 2 H O = MW of 147 2 Dissociates into Ca + Cl + Cl or 3 milliosmoles/millimole (W ater does not count as particles) 10% = 100 m g per ml or 1000 mg per 10 ml vial (147 m g = one millimole)
X mOsms = 3 m Osms = 20.4 m illiosmoles 1000 mg 147 mg
- NaHCO 3 = MW of 84, thus 84 mg = 1 milliequivalent (sodium is m onovalent)
8.4% = 84 m g per ml, thus there is 1 mEq per ml (84 mg/m l, 84 mg = 1 m Eq)
50 ml therefore = 50 mEq (NOTE: The reason sodium bicarbonate injection is 8.4% is to make the concentration 1 mEq per ml for easy dosing.)
- 4% = 40 m g per ml (x) 500 ml = 20,000 mg in the bag
20,000 m g (div by) 2 m g/min = 10,000 m ins (div by) 60 mins/hr = 166.7 hrs
- 1:5000 means one gm in 5000 ml You have 10 ml with 1 gm per 5 ml = 2 gm
thus; 1:5000 would m ean 2 gm in 10,000 m l You must add 9,990 ml of water
- Dextrose 50% means 50 gm in 100 ml or 500 gm in 1000 ml Amino Acids 10% means 10 gm in 100 ml or 40 gm in 400 ml
500 gm dextrose (x) 3.4 cals per gm = 1700 cals 1700 + 160 = 1860 cals per day 40 gm amino acids (x) 4 cals per gm = 160 cals
- 1000 ml + 400 m l + 200 m l + 800 m l = 2400 m l per day
2400 ml/day (div by) 24 hours = 100 ml per hour (x) 10 drops/ml = 1000 drops/hr
1000 drops/hr (div by) 60 mins/hr = 16.7 (or 17) drops per min
- MgSO 4 * 7 H O = MW of 246 2 Mg is divalent, thus 246 mg = 2 mEq of Mg sulfate
246 m g (div by) 2 = 123 m g per mEq 123 m g/mEq (x) 10 mEq = 1230 mg needed
50% = 500 m g per ml 1230 mg (div by) 500 m g/ml = 2.46 m l needed
- 40 mg per 4 m l = 10 mg per ml 10 mg (div by) 10 mg/ml = 1 m l needed
- MW of NaCl = 58.5 Na is monovalent, thus 58.5 mg = 1 m Eq
58.5 m g/mEq (x) 50 mEq = 2925 mg needed
23.4% = 234 m g per ml 2925 mg (div by) 234 m g/ml = 12.5 m l needed
- MW of Na phosphate = 164 So, 164 mg = 3 millimoles of Na per millimole Na phosphate
9 mMoles of Na phosphate (x) 3 = 27 mMoles of sodium
1 mMole of Na = 1 mEq of Na because Na is monovalent
Thus, 27 mMoles = 27 mEq of sodium added with the Na phosphate
- 8.4 mg = 8,400 mcg (div by) 200 puffs = 42 mcg per puff
840 mcg limit per day (div by) 42 mcg per puff = 20 puffs per day
- 1:200,000 = 1 gram per 200,000 ml -or- 1000 mg per 200,000 ml -or- 1 mg per 200 ml
X mg = 1 m g = 20 m l (x) 1 mg = 0.1 mg Epinephrine Amps, 1% 20 ml 200 ml 200 ml = 10 mg per ml
X ml = 1 ml = 0.1 mg (x) 1 ml = 0.01 ml 0.1 mg 10 mg 10 mg
How best to obtain such a small volume? Take 1 ml of Epinephrine, dilute to 100 ml with sterile water, then use 1 ml of the diluted solution.
- 55 pounds = 25 kg of patient (x) 0.3 mg per kg = 7.5 mg per week 2.2 lbs/kg 7.5 mg/week (div by) 7 days/week = 1.1 mg per day (approx)
X ml = 2 m l = 0.22 ml per dose per day 1.1 mg 10 mg
- Ideal Hgb (15) minus Patient Hgb (8) = 7 gram Hgb deficit (x) 55 kg = 385 m g total iron needed
385 m g iron (x) 0.05 (or 5% ) = 19.25 mg iron per dose
19.25 mg per dose (div by) 12.5 m g elemental iron per m l = 1.54 m l per dose
- 560 m g Ca Citrate Tetrahydrate (x) 0.2 (for 20% ) = 112 m g of elemental calcium per tablet
1000 mg of elemental calcium per day = 8.93 (or nine) tablets per day 112 m g of elemental calcium per tablet
The explanation is that the tablets are not pure calcium and most of the tablet is not calcium but the citrate and the water.
- 1:200 = one gram in 200 ml -or- 1000 mg in 200 ml X mg = 1000 mg = 100 mg in 20 ml 200 ml the 20 ml
1:5000 = one gram in 5000 ml X ml = 5000 ml = 500 m l would be produced -or- 1000 mg in 5000 ml 100 mg 1000 mg
- 1:750 = 1 gram in 750 ml X gram s = 1 gram = 5.0467 grams per gallon of 1: 3785 ml (1 gal) 750 ml
X ml = 100 m l = 29.69 ml ~ 1 ounce would be added to one gallon of water to 5.0467 gm 17 grams (17% ) make the 1:750 solution
- KCl = 39 + 36 = 75 for the molecular weight; it is a monovalent salt, so 75 mg = one mEq
30 mEq (x) 75 mg per mEq = 2,250 mg (2.25 gram s) that have been administered over 8 hours
IV set is 15 drops per ml, running at 30 drops per minute = 2 ml per minute
8 hours (x) 60 minutes per hour = 480 m inutes 480 m ins (x) 2 m l/min = 960 m l infused
No 77 continues –
To change X grams = 2.25 grams = 0.234 grams per 100 ml -or- 0.234% to percent 100 ml 960 ml
- Best done by alligation, but also done with mathematics
ALLIGATION METHOD MATHEMATICS METHOD 20 3 = 80 ml 80 ml (x) 0.20 (= 20% ) = 16 grams of morphine
3 X ml = 100 ml = 533.33 ml total volume 16 gms 3 gm 0 17 = 453.33 m l 20 = 533.33 ml 533.33 ml total volume (minus) 80 ml = 453.33 m l
- 0.4 mg (x) 20 caps = 8 mg total 8 mg (div by) 64.8 mg = 1/8th grain
- 325 mg (x) 20 caps = 6,500 mg (div by) 1000 mg/gram = 6.5 grams
- Atropine, 8 mg + Acetaminophen, 6500 mg + Morphine 100 mg (5 mg/cap (x) 20 caps) = 6608 mg
