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Plasma Concentration in Constant Rate Infusion refers to the steady-state concentration of a drug achieved when the rate of drug administration equals the rate of elimination. It represents the concentration maintained in plasma during continuous intravenous infusion.
The calculator uses the formula:
Where:
Explanation: This equation demonstrates that the steady-state plasma concentration is directly proportional to the infusion rate and inversely proportional to the renal clearance of the drug.
Details: Calculating plasma concentration at steady state is crucial for determining appropriate dosing regimens, ensuring therapeutic efficacy while minimizing toxicity, and understanding drug pharmacokinetics during continuous infusion therapy.
Tips: Enter the rate of infusion in mol/s and renal clearance in m³/s. Both values must be positive numbers greater than zero for accurate calculation.
Q1: What is steady-state concentration?
A: Steady-state concentration is the plasma drug concentration achieved when the rate of drug administration equals the rate of elimination, resulting in a constant concentration over time.
Q2: How does renal clearance affect plasma concentration?
A: Higher renal clearance results in lower plasma concentrations at steady state, as the drug is eliminated more rapidly from the body.
Q3: What factors can influence renal clearance?
A: Renal clearance can be affected by kidney function, age, drug interactions, disease states, and individual physiological variations.
Q4: Is this formula applicable to all drugs?
A: This formula is specifically applicable to drugs that follow linear pharmacokinetics and are primarily eliminated through renal excretion.
Q5: How long does it take to reach steady state?
A: It typically takes 4-5 half-lives of the drug to reach approximately 97% of the steady-state concentration during constant rate infusion.