Pharmacology
Antivirals, antifungals and antiparasitics
These medicines complete the anti-infective story the antibiotics section begins. They are separated from antibacterials because the targets differ fundamentally: viruses replicate inside host cells, fungi and parasites are eukaryotes, and the selective margin is narrower in every case.
8 classes across 4 mechanism families.
1. Antifungal agents
These medicines exploit differences between fungal and human cell membranes and cell walls, chiefly through ergosterol synthesis, membrane binding or glucan synthesis.
- Azole antifungals — Ergosterol synthesis inhibitors; hepatic and cytochrome interactions are the defining problem.
- Other antifungals: polyenes, echinocandins and allylamines — Membrane-binding, glucan synthesis and squalene epoxidase inhibitors.
3. Antimycobacterial agents
These medicines treat tuberculosis and related mycobacterial infection, where combination therapy and long duration are dictated by the organism's biology.
- Antimycobacterials — Combination regimens for tuberculosis and leprosy; hepatotoxicity and adherence dominate.
4. Antiparasitic and anthelmintic agents
These medicines act against protozoa and helminths, organisms whose eukaryotic biology leaves a narrower selective margin than bacteria do.
- Antiparasitics and anthelmintics — Antimalarials, antiprotozoals and anthelmintics grouped by target organism.
Studying this the efficient way
Learn the mechanism family first, then the classes inside it. Almost every exam question about spectrum, adverse effects or resistance is really a question about which mechanism a drug belongs to. Each class page ends with a 60-second revision block and the traps students most often fall for.