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Peak-to-trough ratio in pharmacokinetics is the ratio of peak (C max) and trough (C min) levels of a drug over its dosing interval (τ) at steady state.. Peak-to-trough ratio (PTR), also known as peak-to-trough variation or peak-to-trough fluctuation, is a parameter in pharmacokinetics which is defined as the ratio of C max (peak) concentration and C min (trough) concentration over a dosing ...
Onset of action is the duration of time it takes for a drug's effects to come to prominence upon administration. With oral administration , it typically ranges anywhere from 20 minutes to over an hour, depending on the drug in question.
Pharmacokinetic factors determine peak concentrations, and concentrations cannot be maintained with absolute consistency because of metabolic breakdown and excretory clearance. Genetic factors may exist which would alter metabolism or drug action itself, and a patient's immediate status may also affect indicated dosage.
Short term drug side effects are most likely to occur at or near the C max, whereas the therapeutic effect of drug with sustained duration of action usually occurs at concentrations slightly above the C min. [citation needed] The C max is often measured in an effort to show bioequivalence (BE) between a generic and innovator drug product. [4]
Pharmacokinetics (from Ancient Greek pharmakon "drug" and kinetikos "moving, putting in motion"; see chemical kinetics), sometimes abbreviated as PK, is a branch of pharmacology dedicated to describing how the body affects a specific substance after administration. [1]
The onset of action of the antimineralocorticoid effects of spironolactone is relatively slow, with the peak effect sometimes occurring 48 hours or more after the first dose. [1] [24] Canrenone is an antagonist of the MR as is spironolactone, [25] but it is slightly more potent in comparison.
In pharmacology, the area under the plot of plasma concentration of a drug versus time after dosage (called “area under the curve” or AUC) gives insight into the extent of exposure to a drug and its clearance rate from the body. [2]
The plateau principle is a mathematical model or scientific law originally developed to explain the time course of drug action (pharmacokinetics). [1] The principle has wide applicability in pharmacology, physiology, nutrition, biochemistry, and system dynamics.