Fundamentals of Pharmacology

Pharmacology is the science of drugs. It encompasses drug composition, interactions, therapeutic uses, and the effects on biological systems. It's divided into pharmacodynamics and pharmacokinetics, detailing how the body affects drugs and vice versa.

Drugs interact with cellular receptors to elicit responses. The 'Lock and Key' model illustrates this specificity. Agonists activate receptors, while antagonists block them. This interaction's strength, known as affinity, significantly impacts drug efficacy and dosage.

Pharmacokinetics involves four phases: Absorption, Distribution, Metabolism, and Excretion (ADME). Oral drugs dissolve in the stomach, enter the bloodstream, distribute to tissues, metabolize mainly in the liver, and excrete through the kidneys or feces.

Drug metabolism often involves the cytochrome P450 enzyme family, which can be inhibited or induced by other drugs, leading to altered effects. This can cause unexpected drug interactions, emphasizing the need for personalized medication management.

Pharmacogenomics studies how genes affect individual responses to drugs. It's the cornerstone of personalized medicine, allowing tailored drug therapy based on genetic makeup, thus maximizing efficacy while minimizing adverse effects.

Developing a new drug can take over a decade and cost billions. It requires discovery, preclinical testing, clinical trials, and regulatory approval. Less than 10% of candidate drugs make it from phase I trials to approval.

Adverse drug reactions (ADRs) are unwanted effects causing significant morbidity and mortality. ADRs can be dose-related or patient-specific. Recognizing and reporting ADRs is crucial for improving drug safety and patient care.