Bactrim® DS (Trimethoprim / Sulfamethoxazole 160 mg / 800 mg)
Compared with: Blackmores Conceive Well Gold 28 Tablets + 28 Capsules
Bactrim DS (Trimethoprim 160 mg / Sulfamethoxazole 800 mg) is a fixed‑dose antibiotic combination that inhibits sequential steps in bacterial folate synthesis. Indicated for urinary tract infections, Pneumocystis jirovecii pneumonia prophylaxis, and certain skin infections, Bactrim DS offers broad‑spectrum coverage with established efficacy and safety when used as directed.
Trimethoprim – 160 mg

Sulfamethoxazole – 800 mg

Other Popular and Common Names
Co‑trimoxazole DS

Septrin DS (alternate brand)

TMP/SMX 160/800 mg

Sulfamethoxazole–Trimethoprim
Sulfamethoxazole competitively inhibits dihydropteroate synthase, blocking conversion of para-aminobenzoic acid to dihydropteroate.

Trimethoprim selectively inhibits bacterial dihydrofolate reductase, preventing tetrahydrofolate formation.

This sequential blockade of folate synthesis is bactericidal against susceptible organisms.
Acute Uncomplicated Urinary Tract Infections (UTIs)

Pneumocystis jirovecii Pneumonia (PCP): Treatment and prophylaxis in HIV/AIDS

Acute Otitis Media and Sinusitis (when first‑line agents unsuitable)

Traveler’s Diarrhea (enterotoxigenic E. coli)

Skin and Soft Tissue Infections: Community‑acquired MRSA in mild cases
Indication Adult Dose Frequency Duration
Uncomplicated UTI 1 DS tablet (160/800 mg) Twice daily 3 days (women); 7 days (men)*
Acute PCP Treatment 15–20 mg/kg trimethoprim component per day Divided 3–4 times daily 21 days
PCP Prophylaxis 1 DS tablet Once daily Ongoing per risk
Traveler’s Diarrhea 1 DS tablet Twice daily 3–5 days

*Per IDSA guidelines for uncomplicated UTIs .

Administration: Take with full glass of water; can be taken with or without food to reduce GI upset.

Missed Dose: Take as soon as remembered; if within 4 hours of next dose, skip the missed dose—do not double.
Formulation: Film‑coated tablet

Strength: 160 mg trimethoprim / 800 mg sulfamethoxazole

Route: Oral

Legal Status: Prescription Only Medicine
Pregnancy: Category C – Avoid in first trimester; in late pregnancy associated with neonatal kernicterus risk.

Breastfeeding: Small amounts excreted in milk; monitor infant for hyperbilirubinemia.

Pediatric Use: Approved ≥2 months; weight‑based dosing required.

Renal Impairment: Adjust dose or extend interval if creatinine clearance <30 mL/min.

Nausea, vomiting, anorexia

Rash, pruritus

Elevated serum creatinine (reversible)

Serious (rare):

Stevens–Johnson Syndrome / Toxic Epidermal Necrolysis

Aplastic anemia, agranulocytosis, thrombocytopenia

Hyperkalemia, hyponatremia

Interstitial nephritis
Hypersensitivity: Contraindicated in patients with sulfonamide allergy or history of severe cutaneous reactions.

Blood Dyscrasias: Monitor complete blood count for long‑term therapy.

Electrolyte Monitoring: Check serum potassium and sodium in at‑risk patients.

Folate Deficiency: Caution in patients with megaloblastic anemia—supplement folinic acid if indicated.

Drug–Drug Reaction: May potentiate warfarin anticoagulation—monitor INR closely .
Therapeutic Class: Antibiotic Combination

Pharmacologic Class: Sulfonamide + Dihydrofolate Reductase Inhibitor

Legal Category: Prescription Only
Warfarin: Increases INR and bleeding risk—monitor coagulation.

Phenytoin: Inhibits phenytoin metabolism; monitor levels.

Methotrexate: Reduced clearance—monitor for toxicity.

ACE Inhibitors / ARBs: Increased risk of hyperkalemia.

Trimethoprim Alone: Similar interaction profile; rifampin reduces component levels—avoid combination.
Meta‑analysis shows TMP/SMX efficacy in uncomplicated UTIs with clinical cure rates >85 % versus fluoroquinolones .

PCP prophylaxis in HIV reduces incidence by >90 % compared to placebo .

FAQs – Bactrim DS
Q1. Can Bactrim DS treat sinus infections?
A: It is a second‑line option when first‑line (amoxicillin) fails or in penicillin allergy.

Q2. Is monitoring required during long‑term use?
A: Yes—CBC, renal function, and electrolytes every 1–3 months.

Q3. Can it cause sun sensitivity?
A: Yes. Advise photoprotection to prevent photosensitivity rash.

Q4. What if my child vomits after a dose?
A: If within 30 minutes, repeat dose; otherwise continue scheduled dosing.

Q5. Is Bactrim DS safe in G6PD deficiency?
A: Use with caution; risk of hemolysis. Monitor hematologic parameters.

Q6. Can I take it with food?
A: Yes. Food reduces GI upset without affecting absorption.

Q7. How should I store the tablets?
A: Store at room temperature away from moisture and light.
Bactrim DS, Co‑trimoxazole 160/800, TMP/SMX DS, UTI Antibiotic, PCP Prophylaxis, Sulfamethoxazole / Trimethoprim, EZ Chemist, Resistant UTIs, Antibiotic Dosing Guide