FDCs

Fixed-dose combinations (FDCs) are pharmaceutical products that combine two or more active ingredients in a single dosage form at a fixed ratio. They are designed to simplify regimens, improve patient adherence, and ensure that complementary pharmacologic effects are delivered together. In infectious disease care and chronic disease management, FDCs are widely used to promote adherence and therapeutic outcomes.

Common contexts include HIV antiretroviral therapy and tuberculosis treatment, where standardized multi-drug tablets or capsules are routinely prescribed. FDCs are also used in cardiovascular and respiratory conditions, such as combinations of antihypertensives or inhaled therapies in a single dose.

Regulatory evaluation requires demonstration that the fixed combination provides a clinical benefit beyond the individual components and that safety, efficacy, and quality are maintained. Dosing flexibility is restricted, raising concerns when one component is poorly tolerated or when a dose adjustment is needed. Manufacturing must ensure stability of all constituents, consistent delivery of each API, and robust pharmacovigilance.

Advantages include reduced pill burden, improved adherence, simplified supply chains, and potential cost savings. Limitations include the risk of unnecessary exposure if an unnecessary component is included, reduced ability to tailor doses, and potential for unfavorable drug interactions. Some fixed-dose combinations have been withdrawn or restricted due to safety concerns or irrational drug pairing.

In other fields, FDC can stand for First Day Cover in philately, but in pharmacology the term most commonly refers to fixed-dose combinations.