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Therapeutic Calculations from Medscape Example 3

December 23, 2018

How to calculate an estimated number for cumulative sugar as well as kidney function to adjust the drug dose From a group of clips presented by Dr. Eyad Qunaibi, PhD in Pharmacology from the University of Houston, USA, and lecturer and researcher in pharmacology, therapeutics, and pharmacokinetics at Jerash University.. Useful for pharmacy, medicine, and nursing students, and then for the general public interested in obtaining reliable therapeutic information.

Introduction: Case Presentation and Data

Peace be upon you, this is the third example of using the calculators section in the "Medscape" (Medscape) application.

Patient Data:

Age: 60 years old.
Weight: 70 kilograms.
Diagnosis: Suffering from diabetes and taking several medications.
Blood Sugar Test Results:
- Fasting blood sugar: 175 mg/dL.
- Post-prandial blood sugar (2 hours after a meal): 255 mg/dL.
Kidney Function: Serum creatinine is 2.2 mg/dL.

The doctor wishes to add the medication "Januvia" (Januvia) to the treatment plan, and we will use the application to answer questions about dosage and laboratory estimates.

First: Estimating Estimated Hemoglobin A1c (HbA1c Estimation)

The first question: What do you expect the patient's hemoglobin A1c to be? Can we calculate this through "Medscape"?

Yes, hemoglobin A1c is measured in the laboratory, but we can obtain an estimated number through the application:

Go to the Calculators section.
Use the keyword: "A1C estimation from mean plasma glucose".
We first need to calculate the average blood sugar: (175 + 255) ÷ 2 = 215 mg/dL.
When entering the number (215) into the application, we find that the estimated result for HbA1c is 8.2%.

Since the result is somewhat high, the doctor decided to proceed with adding the medication "Januvia".

Second: Determining the Appropriate Dose and Studying Kidney Function

The second question: What is the appropriate dose of "Januvia" for the condition?

Referring to the drug information in "Medscape" for the treatment of type 2 diabetes (Type 2 Diabetes):

Usual dose: 100 mg orally daily.
Dose adjustment (Renal Impairment): The dose should be reduced if there is kidney impairment:
- If creatinine clearance (CrCl) is more than 50 mL/min: no need to adjust the dose.
- If creatinine clearance is between 30 to 50 mL/min: the dose is reduced by half (50 mg daily).

Calculating Creatinine Clearance (Creatinine Clearance)

Since the given data is "serum creatinine" (2.2) and not "creatinine clearance", we will use the application's calculator for conversion, taking into account the following data:

Gender: Female - and it is very important to accurately determine the gender as the equations differ.
Age: 60 years old.
Serum creatinine: 2.2 mg/dL.
Weight: 70 kilograms.

Result: Creatinine clearance is approximately 30 mL/min.

Conclusion and Medical Decision

Based on the previous calculations:

It was found that the patient has reduced kidney function (CrCl = 30 ml/min).
Decision: The dose of "Januvia" should be reduced to 50 mg daily instead of the usual dose.

Thus, we have benefited from the "Medscape" application to obtain an estimated number for hemoglobin A1c and to accurately calculate creatinine clearance to ensure that drug doses are adjusted according to the patient's health condition.