Need help!!!!! Dosage calculations

[Bonzie]

The doctor orders Phenobarbital 10 mg q12h for a child weighing 9 lb. The Pediatric Drug handbook states maintenance dose is 3 to 5 mg/kg/day q12h. Phenobarbital Elixir is available in dosage strength of 20 mg per 5 ml. If safe, what will you administer for one dose?

[bgxyrnf, MSN, RN]

Here's the strategy:

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[lavender59]

9 lb=4.1 kg

4.1 x3=12.3 mg/day 4.1x5=20.5 mg/day

12 hrs x2 =24 hrs per day

10 mgx2=20mg/day

10 mg every 12 hrs is considered a safe dose. It is within the recommended range of 12.3-20.5 mg per day

Available: Order:

20 mg/5mL = 10 mg/x mL

2.5 mL (answer)

You will give 10mg/2.5mL every 12 hrs or per dose

[Rose_Queen, BSN, MSN, RN]

9 lb=4.1 kg

4.1 x3=12.3 mg/day 4.1x5=20.5 mg/day

12 hrs x2 =24 hrs per day

10 mgx2=20mg/day

10 mg every 12 hrs is considered a safe dose. It is within the recommended range of 12.3-20.5 mg per day

Available: Order:

20 mg/5mL = 10 mg/x mL

2.5 mL (answer)

You will give 10mg/2.5mL every 12 hrs or per dose

Simply providing the answer does not help the asker learn how to understand and work through these types of problems. Doing so is actually a disservice to the asker and the patient population he or she will work with in the future.

[debirn918]

9 lb=4.1 kg

4.1 x3=12.3 mg/day 4.1x5=20.5 mg/day

12 hrs x2 =24 hrs per day

10 mgx2=20mg/day

10 mg every 12 hrs is considered a safe dose. It is within the recommended range of 12.3-20.5 mg per day

Available: Order:

20 mg/5mL = 10 mg/x mL

2.5 mL (answer)

You will give 10mg/2.5mL every 12 hrs or per dose

The answer they are looking for is 'dose'. Therefore it would be 10 mg-just what was ordered in the first sentence. You did a great job of making sure all calculations resulted in it being a safe dose. It becomes very confusing if you just say the mL. , because mL is not dose.