Pharmacology and Therapeutics

Scientific interest in pharmacology and therapeutic research.

Pharmacology and therapeutics examines what an active substance does in the body and what the body does to that substance. Therapeutic decisions rest on reading both alongside the clinical evidence.

Two underlying axes

• Pharmacokinetics — absorption, distribution, metabolism and excretion: the path a substance follows through the body. It underlies the determination of dose range and frequency.
• Pharmacodynamics — the effect of the substance on its target; the dose-response relationship and the size of the effect.

Read together, these two make it intelligible why the same dose can produce different results in different patients.

Variation between patients

Factors that alter drug response include renal and hepatic function, age, body composition, pregnancy and comorbidities. Such groups are often only sparsely represented in pre-authorisation studies, so uncertainty grows with distance from the population studied.

Drug interactions

Interactions arise both pharmacokinetically — through shared metabolic pathways — and pharmacodynamically, through effects acting in the same or opposing directions. Where several medicines are taken together, the likelihood of interaction rises steeply with their number.

The benefit-risk balance

No effective medicine carries zero risk. Therapeutic assessment weighs the size of the expected benefit, the frequency and seriousness of possible harm, the availability of alternatives and the patient's own context. That balance is not fixed: it is reassessed as new data is published.

Post-authorisation surveillance

Adverse effects that are rare, that emerge late or that belong to particular subgroups usually become visible only in wide use. A safety profile is therefore not complete at authorisation; it continues to be monitored through pharmacovigilance.