Trimethoprim

Category: pharmacological

Aliases: Component of Bactrim / Septra

Pharmacological Mechanism

Antifolate — inhibits bacterial dihydrofolate reductase (DHFR), blocking tetrahydrofolate synthesis downstream of sulfamethoxazole's DHPS step. Synergistic when combined. Modest renal tubular K+ secretion blockade → hyperkalemia.

Half-Life (t½)

PO: 7.93h, IV: 7.93h

Dosing Guidelines

• PO: Typical 160mg (Range: 100 - 200 mg)

Target Organ Systems

• renal

Interactions

• Repaglinide
• Rosiglitazone
• Pioglitazone