Infectotrimet 50 Saft (Trimethoprim)

Trimethoprim is an antibacterial agent that works against susceptible urinary pathogens and related infections.

• Uncomplicated urinary tract infection: helps eradicate causative bacteria and relieve symptoms.
• Recurrent urinary tract infection prophylaxis: reduces the frequency of infection episodes when taken regularly.
• Travelers' diarrhea caused by susceptible bacteria: may be used as part of combination therapy to treat acute diarrheal illness.

• Trimethoprim selectively inhibits bacterial dihydrofolate reductase, an enzyme required for the conversion of dihydrofolic acid to tetrahydrofolic acid. By blocking this step, the drug impairs bacterial synthesis of nucleic acids and proteins, leading to inhibition of bacterial growth and replication.

Trimethoprim may cause a range of adverse reactions, from mild to severe. Patients should be aware of both common and rare events.

Common Side Effects

• Nausea or vomiting.
• Loss of appetite.
• Mild diarrhea.
• Headache.
• Skin rash or itching.
• Mild dizziness.

Serious or Rare Side Effects

• Severe allergic reactions such as anaphylaxis.
• Stevens‑Johnson syndrome or toxic epidermal necrolysis.
• Blood dyscrasias including agranulocytosis, aplastic anemia, or leukopenia.
• Hepatotoxicity or elevated liver enzymes.
• Acute kidney injury or interstitial nephritis.
• Hyperkalemia, especially when combined with other potassium‑sparing agents.

Before initiating therapy, clinicians should evaluate patient‑specific factors and monitor for potential complications.

• Renal function: assess and adjust dosing in severe renal impairment.
• Hepatic function: monitor liver enzymes during prolonged therapy.
• Pregnancy: use only if clearly needed after risk‑benefit assessment.
• Breastfeeding: caution, as drug may be excreted in milk.
• Drug interactions: review concomitant medications for additive effects.
• Store at ambient temperature: keep in the original container, protect from moisture and light.

Trimethoprim can affect the pharmacokinetics or pharmacodynamics of several medicines. Interactions are grouped by clinical significance.

Major Interactions (Avoid)

• Methotrexate: increased toxicity due to additive folate antagonism.
• Warfarin: enhanced anticoagulant effect, raising bleeding risk.
• Phenytoin: reduced efficacy of trimethoprim, potentially leading to treatment failure.

Moderate Interactions (Monitor Closely)

• Loop diuretics: heightened risk of hyperkalemia.
• ACE inhibitors or ARBs: additive effect on serum potassium levels.
• Sulfonamides: combined folate antagonism may increase toxicity.
• Oral contraceptives: possible reduction in contraceptive effectiveness.