Dosage Calculation: PN Fundamentals Online Practice Assessment 3.0

Administering phenobarbital 6 mg/kg/day PO divided in equal doses every 12 hrs to a patient weighing 44 lb. Available 20 mg/5 mL. How many mL per dose?

15 mL

Patient needs 6 mg per kg a day, in 2 doses that are 12hrs apart & is 44lb; FYI lb/2.2 = x kg

5mL = 20mg SO 1 mL = 4 mg

40lb/2.2 = 20kg so 6mg*20kg = 120mg a day OR 60mg per 12hr dose SO 60mg/4mg= 15mL

Administering cefaclor 500 mg PO every 12 hrs. Available cefaclor 250 mg/5 mL. How many mL per dose?

10 mL

Patient needs 500mg per dose & 5mL = 250mg SO

10mL = 500mg

Administering furosemide 20 mg IM. Available furosemide 10 mg/mL. How many mL for the injection?

2 mL

Patient needs 20mg for the injection & 1mL = 10mg SO 2mL = 20mg

Administering morphine 4 mg IM. Available is 10 mg/mL. How many mL for the injection?

0.4 mL

Patient needs 4mg for the injection & 1mL = 10mg SO 0.4mL = 4mg

(DesiredQuantity)/Have = X mL OR (4mg1mL)/10mg = 0.4mL

Discard suspension how many days after reconstitution?

14 Days

Discard suspension after 14 days

Administering codeine 20 mL oral solution. How many teaspoons (tsp) does this equal?

4 tsp

FYI 1 tsp = 5 mL so

4 tsp = 20 mL

Administering metronidazole 7.5 mg/kg PO. Patient weighs 220 lbs. Available 375 mg/capsule. How many capsules (cap) needed?

2 cap

Patient needs 7.5mg per kg & is 220lb; FYI lb/2.2 = x kg

220lb/2.2 = 100kg; 7.5mg*100kg = 750mg needed

1cap = 375mg SO 2cap = 750mg

Administering famotidine 40 mg PO bedtime. Available 20 mg/tablet. How many tablets (tab) needed?

2 tab

Patient needs 40mg & 1tab = 20mg SO 2tab = 40mg

Include in the teaching for phenytoin oral suspension:

Store medication in cool area

Label states: -100mg/4mL & total is 4mL

-SHAKE WELL before using

-store below 30 C (86F)

-Protect from light

Administering midazolam 0.07 mg/kg IM & patient weighs 50 kg. Available 5 mg/mL. How many mL needed?

0.7 mL

Patient needs 0.07mg per kg & is 50kg

0.07mg*50kg = 3.5mg

1mL = 5mg SO 3.5mg/5mg = 0.7 mL

What's the patient's weight in kg if they weigh 128 lb? (round to nearest tenth)

58.2 kg

FYI lb/2.2 = x kg

SO 128lb/2.2 = 58.1818

Administering cefazolin 1 g IM. Reconstitutes 1 g vial or cefazolin to yield concentration 330 mg/mL. How many mL needed? (nearest whole number)

3 mL

Patient needs 1g for the injection

1mL = 330mg & FYI 1g= 1000mg SO

1000mg/330mg = 3.03mL

Administering haloperidol lactate 3 mg IM. Available 5 mg/mL. How many mL needed?

0.6 mL

Patient needs 3mg & 1mL = 5mg so 3mg/5mg = 0.6mL

Administering eszopiclone 2000 mcg PO. How many [mg] needed?

2 mg

Patient needs 2000mcg converted to mg

FYI 1mg = 1000mcg SO 2mg = 2000mcg

Administer codeine 20 mg PO every 6hrs PRN. Available codeine 10 mg/5mL. How many mL needed?

10 mL

Patient needs 20mg & 5mL = 10mg SO 10mL = 20mg

Administering prednisone 50 mg PO. Available 20mg/tablet. How many tablets (tab) needed?

2.5 tab

Patient needs 50mg & 1tab = 20mg SO 50mg/20mg = 2.5tab

Administering phenytoin 100 mg PO every 8hrs. Available 125 mg/5 mL. How many mL needed per dose?

4 mL

Patient needs 100mg every 8hrs & 5mL = 125mg SO 1mL = 25mg; 100mg/25mg = 4mL

Which prescription needs clarification?

-Desvenlafaxine 50 mg PO qd

-Ketorolac nasal spray 1 spray in each nostril every 6hrs PRN moderate pain

-Oxycodone 10 mg PO every 4hrs PRN severe pain

-Regular insulin 35 units subcut 30 min ac

Desvenlafaxine 50 mg PO qd

FYI prescriptions require medication name &: a unit (ex: mg/mcg/mL), route (ex: PO,/subcut/IM), frequency (ex: ac/q_h/daily [warning: NOT written as qd])

Administering meperidine 75 IM. Available 100 mg/mL. How many mL needed?

0.75 mL

Patient needs 75mg & 1mL = 100mg SO 75mg/100mg = 0.75mL

Administering phenytoin 200 mg PO. Available 125 mg/5 mL. How many mL needed?

8 mL

Patient needs 200mg & 5mL = 125mg SO 1mL = 25mg; 200mg/25mg = 8mL

Administering lorazepam 0.05 mg/kg IM & patient weighs 138 lbs. Available 2 mg/mL. How many mL needed?

1.6 mL

Patient needs 0.05mg per kg & is 138lbs; 1mL = 2mg; FYI lb/2.2 = x kg SO 138lbs/2.2 = 62.7272kg; 0.05mg*62.7272kg = 3.1364mg SO 3.1364mg/2mg = 1.5682mL

Administering benzathine PCN G 1,200,000 units IM. Available 600,000 units/mL. How many mL needed?

2 mL

Patient needs 1,200,000 units & 1mL = 600,000 units SO 2mL = 1,200,000 units

Which prescription needs clarification?

-Lovastatin 20 mg PO once daily

-Diltiazem 30 mg PO 3 times daily; hold for apical pulse rate < 50/min

-Hydrochlorothiazide 50 mg twice daily with meals

-Enoxaparin 30 mg subcut Q12H

Hydrochlorothiazide 50mg twice daily w meals

FYI prescriptions require medication name &: a unit (ex: mg/mcg/mL), route (ex: PO,/subcut/IM), frequency (ex: ac/q_h/daily [warning: NOT written as qd])

Administering 2 tablespoons (Tbsp) ibuprofen. How many mL needed?

30 mL

FYI 1 Tbsp = 15mL

Administering 750,000 units procaine PCN G IM. Available 600,000 units/mL. How many mL needed? (nearest tenth)

1.3 mL

Patient needs 750,000units & 1mL = 600,000units SO

750,000/600,000 = 1.25mL