Test: General Pharmacology - 7 - NEET PG MCQ

The medication that elicits the same effect at a reduced dosage is considered more potent. In this scenario, drug A is ten times more potent than drug B. This information does not provide any insights regarding efficacy, safety, or the duration of action.

Monitoring of therapeutic drugs is unnecessary for oral anticoagulants such as warfarin. The impact of warfarin is assessed through the measurement of prothrombin time or the INR (International Normalised Ratio).

Therapeutic Drug Monitoring (TDM) is a method that involves adjusting a drug's dosage based on its plasma concentration.

Effective TDM requires a strong correlation between drug concentration and therapeutic response. However, it is important to note that there might not be a reliable relationship between the dose administered and plasma concentration.

• TDM is particularly useful for drugs that exhibit significant variability in pharmacokinetics, including absorption, metabolism, and excretion, both within and between individuals.
• This approach is typically applied to medications with a low therapeutic index, such as theophylline, lithium, antiepileptics, immunomodulators, and antiarrhythmics.

TDM is conducted for drugs whose effects are challenging to quantify. For example, the impact of antihypertensive medications can be readily assessed through blood pressure monitoring, making TDM unnecessary in such cases.

Conversely, TDM is not performed for drugs that undergo activation within the body or generate active metabolites, nor is it used when pharmacological tolerance is suspected or when there is a weak correlation between drug concentration and therapeutic effect.

The therapeutic index is an indication of the safety margin of a medication. It is calculated as the ratio of the median lethal dose to the median effective dose:

• T.I. = LD₅₀ / ED₅₀

We can readily track blood glucose levels due to the impact of metformin, meaning that TDM is unnecessary.

TDM is essential for:

• lithium
• digitalis
• phenytoin
• immunosuppressants
• anti-arrhythmics

Therapeutic drug monitoring (TDM) is performed for medications that have a narrow therapeutic index and whose effects cannot be assessed through clinical examination.

Since the antihypertensive effect can be readily evaluated, TDM is not necessary in this case.