Pharmacological Drugs

Chapter Overview

Pharmacology is the branch of medicine concerned with the uses, effects, and modes of action of drugs. The pathway to bringing a new therapeutic drug to market is highly structured, beginning with drug discovery (identifying target molecules and lead compounds) and preclinical development (testing in vitro and in vivo on animals for basic safety and efficacy). This is followed by clinical development in human subjects across Phase 1, Phase 2, and Phase 3 trials. Successful candidates undergo rigorous regulatory review by agencies like the FDA before approval, followed by Phase 4 post-marketing surveillance to monitor long-term safety in the general population.

Antibiotics are chemical substances that kill or inhibit the growth of bacteria. Their modes of action are highly selective, targeting bacterial structures that differ from human cells. These include inhibiting cell wall synthesis (e.g., penicillins), disrupting cell membrane function, inhibiting protein synthesis (e.g., tetracyclines by binding to ribosomes), or interfering with nucleic acid synthesis. Because viruses lack their own cellular machinery and replicate inside host cells, treating viral infections requires antivirals and antiretrovirals that selectively inhibit viral replication cycles without damaging host tissue.

Monoclonal antibodies (mAbs) represent a major advancement in targeted therapy. These are laboratory-engineered proteins designed to bind to specific antigens on pathogens or diseased cells. The primary advantages of monoclonal antibodies include high target specificity, lower off-target toxicity, and long half-lives in the bloodstream. When compared to traditional small-molecule drugs, monoclonal antibodies offer unmatched precision in treating cancers, autoimmune diseases, and chronic infections. Mastering these pharmacological concepts is essential for HSSC-II SLO-based assessments.