Nonsteroidal

Nonsteroidal refers to substances that do not possess the steroid nucleus or are not derived from steroids. In chemistry, steroids are characterized by a four-ring cyclopentanoperhydrophenanthrene structure, and nonsteroidal compounds lack this core. The term is used across disciplines to contrast compounds with different structural classes and receptor interactions.

In pharmacology, nonsteroidal drugs include a broad range of agents that act through diverse mechanisms. A prominent subgroup is nonsteroidal anti-inflammatory drugs (NSAIDs), which reduce inflammation, pain, and fever by inhibiting cyclooxygenase enzymes (COX-1 and COX-2) and lowering prostaglandin synthesis. Examples include ibuprofen, naproxen, diclofenac, and ketorolac; aspirin is also commonly categorized with NSAIDs. NSAIDs are effective but can cause gastrointestinal irritation, ulcers, bleeding, and renal or cardiovascular risks with prolonged use.

The nonsteroidal descriptor also appears in endocrine and cancer therapies. Nonsteroidal selective estrogen receptor modulators (SERMs) such as tamoxifen and raloxifene bind to estrogen receptors without being steroids, offering tissue-specific effects. Nonsteroidal antiandrogens, like bicalutamide and enzalutamide, block androgen receptors without steroidal structure and are used in prostate cancer treatment. These examples illustrate how nonsteroidal compounds can achieve therapeutic goals through targeted receptor modulation rather than steroid receptor pathways.

Overall, nonsteroidal is a structural classification distinguishing compounds from steroids, while encompassing a wide range of therapeutic agents and research tools with varied mechanisms and safety profiles.