A Comprehensive Clinical and Pharmacological Review of Sulfadoxine-Pyrimethamine

Section 1: Introduction and Pharmacological Profile

1.1. Overview and Drug Classification

Sulfadoxine-Pyrimethamine (SP) is a fixed-dose combination medication that has played a pivotal and evolving role in the global fight against malaria and other protozoal infections.[1] It is broadly classified as an anti-infective and antiprotozoal agent, with its primary application being the treatment and, more significantly in the modern era, the prevention of malaria caused by the parasite

Plasmodium falciparum.[2] The combination consists of two distinct active pharmaceutical ingredients, each with a specific mechanism of action that contributes to a potent synergistic effect.

The first component, Sulfadoxine, is a long-acting sulfonamide antibiotic.[1] As a member of the sulfonamide class, its primary pharmacological roles are as an antibacterial and antimalarial drug.[2] The United States Food and Drug Administration (FDA) formally categorizes sulfadoxine within the Established Pharmacologic Class [EPC] of Sulfonamides.[2] Its prolonged duration of action is a key feature that makes it suitable for intermittent preventive therapies.

The second component, Pyrimethamine, is an antiprotozoal agent belonging to the diaminopyrimidine class of drugs.[1] It functions as an antifolate compound, with a structure and mechanism of action similar to that of another antimalarial, proguanil.[3] Pyrimethamine is also indicated for the treatment of other parasitic diseases, including toxoplasmosis and cystoisosporiasis, often in combination with other agents.[6]