DUE DATE: 21 APRIL 2026
QUESTION 1 [25]
1.1 Define the therapeutic index and explain its significance in pharmacology. (5)
The therapeutic index (TI) is a pharmacological measure used to assess the relative safety
of a drug. It represents the ratio between a drug’s toxic dose and its effective dose,
essentially comparing the dose required to produce a harmful effect with the dose required
to achieve the desired therapeutic effect. A high therapeutic index indicates that there is a
wide margin between the dose that is effective and the dose that could be toxic, which
implies that the drug can be administered with a lower risk of adverse effects. Conversely, a
low therapeutic index suggests a narrow safety margin, requiring precise dosing, careful
monitoring, and often individualized adjustments to avoid toxicity. Clinically, the
therapeutic index is significant because it guides healthcare providers in determining safe
dosing regimens, monitoring patient responses, and preventing overdose or underdose.
Drugs with a narrow therapeutic index, such as certain anticoagulants or antiepileptics,
demand particularly vigilant therapeutic monitoring, while drugs with a wide therapeutic
index, like many antibiotics, provide more flexibility in dosing without immediate risk of
severe toxicity. Therefore, understanding the therapeutic index is crucial for maximizing
therapeutic benefit while minimizing the risk of harm, making it a fundamental concept in
both clinical and pharmacological decision-making.
1.2 What is the difference between potency and efficacy in drug action? (5)
Potency and efficacy are two core concepts in pharmacology that describe different aspects
of a drug’s effect. Potency refers to the amount of a drug required to produce a given effect;