Question

ordered: eloxatin® 50 mg in 500 ml d5w over 1.5 h using 20 gtt/ml tubing
dosage available: eloxatin® 5 mg/ml
(source: math and dosage calculations for healthcare professionals (booth, 5, isbn 1259166260) > chapter 15: intravenous calculation
a) calculate the mount to administer in ml per dose.
b) calculate the flow rate in milliliters per hour.
c) calculate number of drops per minute in gtt per minute.

Explanation:

Part a)

Step1: Use the formula \(V=\frac{D}{H}\times Q\)

Here, \(D = 50\space mg\) (desired dose), \(H=5\space mg/mL\) (dose on - hand), and \(Q = 1\space mL\) (quantity of the available dose).

$$V=\frac{50\space mg}{5\space mg/mL}\times1\space mL$$

Step2: Calculate the value

$$V = 10\space mL$$

Part b)

Step1: Use the formula \(Flow\space rate=\frac{Volume}{Time}\)

The volume \(V = 500\space mL\) and time \(t=1.5\space h\)

$$Flow\space rate=\frac{500\space mL}{1.5\space h}$$

Step2: Calculate the value

$$Flow\space rate=\frac{500}{1.5}\approx333.33\space mL/h$$

Part c)

Step1: Use the formula \(gtt/min=\frac{Volume\times gtt/mL}{Time\space (in\space minutes)}\)

The volume \(V = 500\space mL\), \(gtt/mL = 20\space gtt/mL\), and time \(t = 1.5\space h=1.5\times60 = 90\space min\)

$$gtt/min=\frac{500\times20}{90}$$

Step2: Calculate the value

$$gtt/min=\frac{10000}{90}\approx111.11\space gtt/min$$

Answer:

a) \(10\space mL\)
b) \(333.33\space mL/h\)
c) \(111.11\space gtt/min\)