Final answer:
To determine the daily maintenance dose for a 70 Kg patient given a loading dose of 30 mg of a drug with a 5 L/kg Vd and a 3-hour half-life, one must calculate the drug's clearance and use it along with the bioavailability and the desired steady state concentration to find the maintenance dose.
Step-by-step explanation:
The question involves determining the correct daily maintenance dose of a drug for a 70 Kg patient who has been given an initial loading dose of 30 mg. This drug has a volume of distribution (Vd) of 5 L/kg and an elimination half-life of 3 hours. To calculate the maintenance dose, you can use the formula: MD = (CL x Css) / F, where MD is the maintenance dose, CL is the clearance of the drug, Css is the steady state concentration (assumed to be the same as the loading dose), and F is the bioavailability of the drug. Given the half-life, you can find the elimination rate constant (k) using the formula k = 0.693/t1/2 and then solve for clearance (CL) using the equation CL = k x Vd. Finally, you can use the calculated clearance to determine the maintenance dose that will maintain the desired drug concentration in the patient's system.
The half-life of a drug, the rate at which it is eliminated, and whether or not the drug is dose or time dependent are essential to consider when determining both the loading and maintenance dosages for a patient. For drugs with longer half-lives, overmedication can lead to prolonged periods of potentially toxic drug levels, hence the importance of accurate dosage calculation.