Halogen-Containing Drugs in 2025: A Record Year for the Therapeutic Use and Synthesis of FDA-Approved Small Molecules

Halogens, particularly fluorine, chlorine, and bromine, play a pivotal role in modern drug discovery and development. Their incorporation into drug molecules significantly influences physicochemical properties, including lipophilicity, metabolic stability, and target binding affinity. Fluorine, the most commonly used halogen, enhances bioavailability and receptor interactions, as seen in several blockbuster drugs. Chlorine and bromine contribute to hydrophobic interactions and modulate pharmacokinetics, while iodine is less frequently utilized due to its larger atomic size and reactivity. The strategic placement of halogens in drug scaffolds has led to the success of numerous FDA-approved pharmaceuticals across therapeutic areas, including oncology, infectious diseases, and central nervous system disorders. This review explores the structure-activity relationships (SAR) of halogen-containing drugs, highlighting recent approvals (2025), their synthesis (with yields, when available), therapeutic use, and, when experimentally available, the interaction with their biological target macromolecules.