What does the term 'trough' refer to in pharmacology?

In pharmacology, the term 'trough' specifically refers to the lowest concentration of a drug in the bloodstream after it has been administered. This measurement is crucial because it helps clinicians understand how much of the drug remains in the body at a given time before the next dose is scheduled, which is particularly important in managing medication regimens effectively and safely. The trough level indicates when the drug is at its minimum effectiveness and helps in assessing the timing for the next administration, ensuring optimal therapeutic effects without risking toxicity. Understanding this concept is vital for monitoring drug therapy, especially for medications that have narrow therapeutic ranges or require precise dosing intervals.