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Drug handling: Suggested questions

Last updated: Thursday, November 22, 2018


They may not apply to every situation you come across, but these are some of the questions you should be thinking about in practice:

The Medicine


  • When was the medicine started, and was a loading dose given? If started very recently, then there may not have been time for the drug to reach steady state. 
  • What is the current dose, and have there been any recent changes in the dose? You need to know if the levels represent a long-term stable dosing regimen or a changing one that might not be at steady state. 
  • Check if any previous drug levels have been taken and if so, check the time they were taken in relation to dosing. This allows you to see any patterns in levels related to dose and whether they reflect peak levels. Be careful to confirm the units of measurement.
  • Are there any drug interactions that might affect clearance? A key factor that can cause drug levels to fall or increase.

The Patient


  • What is the patient's age and weight? To help in determining suitable dosage on the basis of body size and age. Age may  affect clearance or response.
  • Any medical conditions that may affect levels? Does the patient have kidney or liver dysfunction that might affect the clearance of the medicine? Are there any other medical conditions that might affect levels or drug response (e.g. low albumin levels may increase the amount of free phenytoin in the plasma)?
  • Is the patient responding well to their treatment? Suggests that levels may be therapeutically adequate.
  • Do they have potential signs of toxicity? Suggests that levels may be too high. The nature and severity of any reactions will help determine if a dose reduction is a suitable way forward or if treatment must be stopped (temporarily or permanently).

Going Forward


  • What will be done if the patient's drug levels are too high or too low? Have the probable reasons been ascertained, is there a plan to manage the situation, and how will this be prevented in future?
  • Who will monitor drug response and any drug levels after today? Maybe this is a junior doctor over the weekend, or a GP after discharge. Has this responsibility been communicated properly, and does the person know what they must do?