Question

When are trough levels collected?

1) Before the administration of the drug
2) Immediately after the administration of the drug
3) At the peak of the drug's effect
4) At a specific time interval after the administration of the drug

Answer 1

Trough levels are collected before the administration of the drug to ensure that drug concentrations remain within a therapeutic range without causing toxicity. It is part of therapeutic drug monitoring, especially for drugs with a narrow therapeutic index.

Step-by-step explanation:

Trough levels are typically collected before the administration of the drug (option 1), as they represent the lowest concentration of the drug in the bloodstream before the next dose. This measurement is essential for drugs with a narrow therapeutic range, where maintaining the right balance between efficacy and toxicity is critical. Trough levels help ensure that drug concentrations stay within a safe and effective range.

Therapeutic drug monitoring (TDM) is the practice of measuring drug concentrations in plasma or serum to tailor dosages to individual needs, based on factors such as the drug's half-life, route of administration (oral or intravenous), and the drug’s absorption in the gastrointestinal tract.

The dosage of a drug is determined by considering patient-specific factors like mass, liver or kidney function, and also the pharmacokinetics of the drug, including half-life, peak levels, and whether the drug is time-dependent or dose-dependent in its action.