Question

You inject (intravenously) a 70 Kg patient with 30 mg of drug that has a Vd of 5 L/Kg and an elimination half life of 3 hr.

Three hours after injecting the drug, what is the expected plasma drug concentration?

Answer 1

The expected plasma drug concentration three hours after injecting the drug is approximately 0.0429 mg/L.

Step-by-step explanation:

To calculate the expected plasma drug concentration three hours after injecting the drug, we need to use the formula:

C = Cp * (0.5)^(t/t1/2)

Where:

• C is the expected plasma drug concentration
• Cp is the initial drug concentration (30 mg / (70 Kg * 5 L/Kg) = 0.0857 mg/L)
• t is the time elapsed (3 hours)
• t1/2 is the elimination half-life of the drug (3 hours)

Plugging the values into the formula, we get:

C = 0.0857 mg/L * (0.5)^(3/3) = 0.0429 mg/L

Therefore, the expected plasma drug concentration three hours after injecting the drug is approximately 0.0429 mg/L.