Therapeutic Drug Monitoring:
01) What is the definition of therapeutic drug monitoring?
Therapeutic drug monitoring is a means of measuring the
concentration of a drug in a biological fluid or sample most
commonly this is conducted in plasma, serum or blood.
• The measurement obtained by conducting drug therapeutic
monitoring help us to visualise the dosage regime for specific
patients and by doing this helps us to maintain that drug in a target
range
• Drug therapeutic monitoring is a means of sampling that
concentration of drug to make sure that it’s within the therapeutic
window
02) What are the 6 most common reasons why Therapy Drug
Monitoring is required?
1. Monitoring patient compliance and adherence to medication
2. Individualise patient therapy = we would want to do that early on
as we are putting on a new drug towards a patient and pulling
towards that steady state level to make sure the balance is right. And
also when we want to make dosage changes to keep the
concentration within the steady state
3. Suspected or avoiding any form of toxicity in the patient = we may
want to rule out or understand if that’s being caused by an elevated
level of drug
4. Diagnosing under treatment = this is where we may be noticing
that there is an increase in symptoms in the patients. This tells us if
there’s sufficient amount of drug to remove the symptoms the
patients are experiencing
5. Monitoring and detecting drug interactions = being able to
understand the influence of these drug-drug interactions which may
be sinister as it can be toxic or generate specific symptoms
6. Guiding withdrawal of therapy
, 03) Explain the process for reading dosage decision?
• First a diagnosis is made and then based on that diagnosis a
particular drug is selected for that patient. Then a dosage schedule
is designed to reach a target plasma concentration and then the
drug is administered
• Then there are 2 key aspects that we can do to understand the
efficacy of the medications on the patient
• Patient assessment e.g ask about the symptoms to look for positive
changes, measure other biochemical markers e.g blood pressure
• Measuring drug concentrations are determined e.g we can see if
the concentration of the drug is within the therapeutic window
• Once we sequester both of these sets of information, we can gain a
pharmacokinetic model which we can use and apply to
understand the behaviour of the drug within a particular patient
• If the pharmacist feels that the drug concentration is not in the right
range or going into the toxic range/sub-therapeutic area
appropriate dosage adjustment can be made
• This cycle can be continuous until we reach a real steady state
concentration of the drug
• Therapeutic drug monitoring comes at the point where we take a
sample from the patient to measure. That sample is take for
analysis where it’s processed and measured by array of different
techniques e.g sensors/wearables, immunoassays or
chromatography
• Then the data that’s generated provides a concentration that we
can return back to the clinical stand in order to use for clinical
decision making
• Based on the data that’s provided by therapeutic drug monitoring,
the clinician or the clinical team can make a medical judgement
on whether the dosing is correct or not. If the dosing is not correct,
they can again personalise the dose to that particular patient
01) What is the definition of therapeutic drug monitoring?
Therapeutic drug monitoring is a means of measuring the
concentration of a drug in a biological fluid or sample most
commonly this is conducted in plasma, serum or blood.
• The measurement obtained by conducting drug therapeutic
monitoring help us to visualise the dosage regime for specific
patients and by doing this helps us to maintain that drug in a target
range
• Drug therapeutic monitoring is a means of sampling that
concentration of drug to make sure that it’s within the therapeutic
window
02) What are the 6 most common reasons why Therapy Drug
Monitoring is required?
1. Monitoring patient compliance and adherence to medication
2. Individualise patient therapy = we would want to do that early on
as we are putting on a new drug towards a patient and pulling
towards that steady state level to make sure the balance is right. And
also when we want to make dosage changes to keep the
concentration within the steady state
3. Suspected or avoiding any form of toxicity in the patient = we may
want to rule out or understand if that’s being caused by an elevated
level of drug
4. Diagnosing under treatment = this is where we may be noticing
that there is an increase in symptoms in the patients. This tells us if
there’s sufficient amount of drug to remove the symptoms the
patients are experiencing
5. Monitoring and detecting drug interactions = being able to
understand the influence of these drug-drug interactions which may
be sinister as it can be toxic or generate specific symptoms
6. Guiding withdrawal of therapy
, 03) Explain the process for reading dosage decision?
• First a diagnosis is made and then based on that diagnosis a
particular drug is selected for that patient. Then a dosage schedule
is designed to reach a target plasma concentration and then the
drug is administered
• Then there are 2 key aspects that we can do to understand the
efficacy of the medications on the patient
• Patient assessment e.g ask about the symptoms to look for positive
changes, measure other biochemical markers e.g blood pressure
• Measuring drug concentrations are determined e.g we can see if
the concentration of the drug is within the therapeutic window
• Once we sequester both of these sets of information, we can gain a
pharmacokinetic model which we can use and apply to
understand the behaviour of the drug within a particular patient
• If the pharmacist feels that the drug concentration is not in the right
range or going into the toxic range/sub-therapeutic area
appropriate dosage adjustment can be made
• This cycle can be continuous until we reach a real steady state
concentration of the drug
• Therapeutic drug monitoring comes at the point where we take a
sample from the patient to measure. That sample is take for
analysis where it’s processed and measured by array of different
techniques e.g sensors/wearables, immunoassays or
chromatography
• Then the data that’s generated provides a concentration that we
can return back to the clinical stand in order to use for clinical
decision making
• Based on the data that’s provided by therapeutic drug monitoring,
the clinician or the clinical team can make a medical judgement
on whether the dosing is correct or not. If the dosing is not correct,
they can again personalise the dose to that particular patient
