Last updated: October 6, 2026
Bactrim DS is the branded 800 mg sulfamethoxazole/160 mg trimethoprim tablet. Its commercial profile is that of a mature, low-cost anti-infective rather than an innovative branded product. U.S. patent and regulatory exclusivity have expired, generic competition is established, and no public company reports Bactrim DS revenue as a standalone product line. Financial performance is therefore driven by prescription volume, generic pricing, supply availability, and channel share rather than brand-led price growth.
What is Bactrim DS and how is it used?
Bactrim DS combines sulfamethoxazole and trimethoprim in a fixed-dose oral tablet. Each double-strength tablet contains 800 mg of sulfamethoxazole and 160 mg of trimethoprim.
FDA-approved and established clinical uses include:
- Urinary tract infections
- Acute exacerbations of chronic bronchitis
- Shigellosis
- Traveler's diarrhea caused by susceptible organisms
- Pneumocystis jirovecii pneumonia treatment and prophylaxis
- Selected skin and soft-tissue infections
- Certain opportunistic infections in immunocompromised patients
The product has been marketed in the United States for decades. Its clinical value depends on the combination's activity against susceptible organisms, oral bioavailability, low acquisition cost, and broad familiarity among prescribers. The label also carries important warnings involving severe cutaneous reactions, blood dyscrasias, hyperkalemia, renal impairment, and interactions with drugs such as warfarin and certain renin-angiotensin system inhibitors (FDA, 2023).
What is the Orange Book status of Bactrim DS?
Bactrim DS has no remaining meaningful branded patent or regulatory exclusivity protection in the United States.
| Item |
Status |
| Active ingredient |
Sulfamethoxazole/trimethoprim |
| Dosage form |
Oral tablet |
| Strength |
800 mg/160 mg |
| Original U.S. approval |
1970s |
| Reference product |
Bactrim/Bactrim DS |
| New chemical entity exclusivity |
Expired |
| Brand patent exclusivity |
Expired |
| Orange Book commercial position |
Legacy reference product with generic competition |
| Paragraph IV exposure |
Commercially immaterial because core protection expired decades ago |
| Generic substitution |
Widely available |
The FDA Orange Book lists approved generic versions through abbreviated new drug applications. The commercial issue is therefore not whether a generic can enter after challenging a current Bactrim DS patent. The issue is price, supply, manufacturing economics, and distribution access (FDA, 2024a).
What patents protect Bactrim DS?
No active composition-of-matter patent protects the sulfamethoxazole/trimethoprim combination in the U.S. market. The original combination and tablet technology are long past normal patent terms.
Formulation patents
Bactrim DS is a conventional immediate-release tablet. Publicly available regulatory records do not indicate an active, commercially significant formulation patent that blocks generic immediate-release tablets.
Potential differences among products can involve:
- Excipients
- Tablet shape and color
- Scoring
- Packaging
- Manufacturing controls
- Dissolution specifications
These differences do not create a meaningful patent barrier when an ANDA applicant demonstrates pharmaceutical equivalence and bioequivalence.
Method-of-use patents
The core uses of Bactrim DS are established anti-infective indications. No current method-of-use patent appears to control the principal U.S. indications for the product. Physicians may prescribe the combination for clinically accepted uses beyond the original label, but those uses generally do not create enforceable exclusivity for the brand.
Manufacturing and supply-chain barriers
The relevant barriers are operational rather than patent-based. They include:
- Reliable production of both active ingredients
- Quality control for combination content uniformity
- FDA compliance at API and finished-dose facilities
- Capacity allocation for low-margin tablets
- Inventory management during seasonal infection peaks
- Procurement contracts with wholesalers, hospitals, and government buyers
These constraints can temporarily affect availability without changing the long-term competitive structure.
When does Bactrim DS lose exclusivity?
Bactrim DS lost practical exclusivity many years ago. The product is not approaching a future loss-of-exclusivity event.
| Exclusivity category |
Bactrim DS position |
| Patent term |
Expired |
| Orphan exclusivity |
None for the legacy product |
| Pediatric exclusivity |
Not commercially relevant to current competition |
| New clinical investigation exclusivity |
None controlling the core product |
| Generic entry |
Already established |
| Brand protection outlook |
No material renewal event |
This makes Bactrim DS different from newer branded antibiotics, where patent expiry, pediatric extensions, or formulation patents can determine launch timing. For Bactrim DS, generic supply is already the market standard.
How many manufacturers compete with Bactrim DS?
The U.S. market includes the reference product and multiple generic suppliers. The exact supplier count changes as products are approved, discontinued, acquired, or removed from distribution.
Generic manufacturers and distributors active in the broader sulfamethoxazole/trimethoprim market have included large generic companies, specialty suppliers, and contract manufacturing organizations. FDA product databases identify multiple approved ANDAs for the 800 mg/160 mg tablet presentation (FDA, 2024b).
Competition occurs at several levels:
- National retail pharmacies and wholesalers
- Hospital and health-system purchasing contracts
- Medicaid and managed-care formularies
- Government procurement
- Mail-order and specialty pharmacy channels
The reference brand generally has limited leverage where pharmacists can substitute an approved generic and payers impose generic-first policies.
What drives Bactrim DS market demand?
Demand is stable but clinically selective. The product is not a high-growth anti-infective, yet it retains recurring use in several segments.
Urinary tract infections
Trimethoprim-sulfamethoxazole remains an option for uncomplicated urinary tract infections when local resistance is acceptable and the pathogen is susceptible. The Infectious Diseases Society of America has recognized resistance thresholds and patient-specific factors that limit empiric use in some settings (Gupta et al., 2011).
Nitrofurantoin and fosfomycin compete directly in uncomplicated cystitis. Local resistance patterns, renal function, allergy history, pregnancy status, prior culture results, and treatment setting determine product selection.
Skin and soft-tissue infections
Bactrim DS remains widely used against community-associated methicillin-resistant Staphylococcus aureus in selected patients. Doxycycline, clindamycin, and other agents compete in this segment. Bactrim DS has less reliable coverage for some streptococcal infections, which can affect combination therapy or product selection.
Pneumocystis pneumonia
The combination remains a standard treatment and prophylaxis option for Pneumocystis jirovecii pneumonia. This use creates a more specialized demand base than routine outpatient infections and supports continued institutional purchasing (NIH, 2024).
Antimicrobial stewardship
Stewardship programs can restrain inappropriate prescribing, but they do not eliminate demand. They favor culture-directed therapy and narrower-spectrum use where appropriate. Bactrim DS can benefit when susceptibility is documented because it is inexpensive and orally administered.
How does Bactrim DS compare with competing antibiotics?
| Clinical segment |
Bactrim DS position |
Main competitors |
Commercial implication |
| Uncomplicated UTI |
Useful when local resistance and susceptibility support use |
Nitrofurantoin, fosfomycin, selected beta-lactams |
Price is low, but resistance limits share |
| MRSA skin infection |
Common oral option in selected cases |
Doxycycline, clindamycin |
Demand varies with local MRSA prevalence |
| Pneumocystis pneumonia |
Established treatment and prophylaxis option |
Atovaquone, dapsone-based regimens, pentamidine |
Institutional and immunocompromised-patient demand |
| Shigellosis and enteric infections |
Selective use based on susceptibility |
Azithromycin, ceftriaxone, fluoroquinolones |
Resistance and guideline changes reduce predictability |
| Nocardia and other opportunistic infections |
Important in selected cases |
Imipenem, amikacin, linezolid and other agents |
Specialist-driven demand |
Bactrim DS has a cost advantage over many branded or newer anti-infectives. Its main commercial weakness is that clinical utility depends heavily on resistance and patient safety factors.
What is the financial trajectory for Bactrim DS?
Bactrim DS does not have a publicly reported standalone revenue trajectory. The original brand owner and generic manufacturers generally report products within broader portfolios, making product-level sales, gross margin, and market share unavailable in public filings.
The likely financial trajectory has four phases:
1. Branded growth phase
The product generated branded pharmaceutical revenue when it had limited direct competition and broader use in common infections.
2. Generic erosion phase
After patent and regulatory exclusivity expired, generic entry reduced average selling prices and shifted volume from the brand to lower-cost suppliers. This is the dominant structural event in the product's financial history.
3. Mature-volume phase
The market stabilized around recurring demand from outpatient infections, hospitals, and prophylaxis. Unit volume can remain durable even while revenue declines because price per tablet is low.
4. Supply-sensitive mature phase
Current economics depend on:
- API costs
- Labor and compliance costs
- Wholesale acquisition terms
- Reimbursement rates
- Contract renewals
- Manufacturing disruptions
- Competitor exits
- Temporary shortages
For a mature generic, a competitor's exit can raise market prices temporarily. New entrants or restored supply can reverse the increase quickly. This creates volatility in unit economics without creating durable monopoly pricing.
What is the revenue exposure for manufacturers?
Bactrim DS is unlikely to be a material revenue driver for diversified pharmaceutical companies. It is more relevant as:
- A portfolio filler for generic manufacturers
- A hospital-contract product
- A low-cost oral anti-infective
- A product supporting manufacturing utilization
- A recurring but low-margin item in broad generic portfolios
The financial risk is asymmetric. A company is unlikely to suffer major group-level revenue loss from Bactrim DS alone unless it has unusually concentrated exposure. The greater risk is margin compression, supply disruption, product discontinuation, or regulatory remediation at a manufacturing site.
For the reference brand, the commercial risk is higher because generic substitution limits pricing power. For generic suppliers, the opportunity is volume-based and depends on disciplined cost control.
What is the FDA regulatory status of Bactrim DS?
Bactrim DS remains an FDA-approved prescription product. The FDA-approved label includes dosing, contraindications, warnings, adverse reactions, drug interactions, and use restrictions for specific populations (FDA, 2023).
Regulatory considerations include:
- Renal dose adjustment
- Contraindication or caution in severe sulfonamide hypersensitivity
- Risk of hyperkalemia
- Potential interaction with warfarin
- Risk of serious skin reactions
- Avoidance or careful use in certain pregnancy and neonatal settings
- Monitoring in patients with renal or hematologic risk factors
The regulatory profile is well established. There is no pending innovative approval event that would materially change the product's market structure.
Are there Paragraph IV challenges or Bactrim DS patent lawsuits?
Paragraph IV litigation is not a central commercial issue for Bactrim DS because the underlying product patents expired long ago. Generic applicants did not need to rely on a late-stage patent challenge to create the current market; multiple generic products have already entered.
Publicly significant recent litigation involving the core Bactrim DS tablet is not a primary market variable. Any disputes involving manufacturers are more likely to concern:
- Product liability
- Antitrust allegations
- Supply contracts
- Manufacturing quality
- Distribution
- Regulatory compliance
These issues differ from patent litigation and generally do not restore product exclusivity.
Are there licensing deals for Bactrim DS?
No major current licensing transaction appears to define the Bactrim DS market. The product's economics do not depend on a novel delivery platform, biologic manufacturing technology, or proprietary formulation license.
Commercial arrangements are more likely to involve:
- Generic distribution
- Private-label supply
- Contract manufacturing
- Hospital purchasing
- Wholesaler agreements
- Portfolio acquisitions
Such arrangements can change supplier share without changing the underlying patent position.
What generic launch scenarios exist for Bactrim DS?
Base case: stable generic supply
Multiple suppliers continue to meet routine demand. Prices remain low, and the brand retains limited share.
Upside case for suppliers: competitor withdrawal
A manufacturing problem, compliance action, API shortage, or commercial discontinuation removes one or more suppliers. Remaining manufacturers may gain volume and temporary pricing leverage.
Downside case: demand erosion
Resistance, guideline changes, stewardship restrictions, or substitution by nitrofurantoin, fosfomycin, doxycycline, or other agents reduces prescription volume.
Brand downside case: continued substitution
Pharmacy and payer policies continue directing prescriptions to generic suppliers, limiting the reference brand's ability to recover share.
How strong is the Bactrim DS patent estate?
The patent estate is commercially weak because the relevant protection has expired and generic competition is established.
| Patent-estate factor |
Assessment |
| Composition protection |
Expired |
| Core formulation protection |
No material current barrier |
| Method-of-use protection |
No controlling exclusivity identified |
| Generic entry barrier |
Low |
| Patent litigation leverage |
Minimal |
| Manufacturing know-how |
Operational value only |
| Regulatory moat |
Limited to approved-product compliance |
| Long-term pricing power |
Very low |
The product can remain commercially durable without having a strong patent estate. Its durability comes from clinical familiarity, low cost, broad generic availability, and use in several distinct treatment settings.
Key Takeaways
- Bactrim DS is a mature sulfamethoxazole/trimethoprim product with no meaningful remaining U.S. patent exclusivity.
- Generic competition is established, making price and supply more important than patent strategy.
- FDA approval remains active for the established product and generic equivalents.
- No standalone Bactrim DS revenue series is publicly reported by major manufacturers.
- Financial performance is likely stable at the unit level but low-margin at the product level.
- Demand is supported by UTI, MRSA, Pneumocystis, and selected opportunistic-infection uses.
- Resistance, antimicrobial stewardship, renal safety, and adverse-effect concerns constrain growth.
- Nitrofurantoin, fosfomycin, doxycycline, clindamycin, atovaquone, and other agents create clinical competition.
- The principal commercial risks are supply disruption, manufacturing compliance, price erosion, and declining clinical preference.
- Patent litigation and Paragraph IV activity are not material drivers of the current Bactrim DS market.
FAQs
Is Bactrim DS still a branded drug?
Yes. Bactrim DS remains the reference branded product, but generic sulfamethoxazole/trimethoprim tablets dominate many dispensing channels.
Is Bactrim DS more expensive than generic sulfamethoxazole/trimethoprim?
Usually, the brand carries a higher acquisition or reimbursement cost than generic equivalents. Actual patient cost depends on insurance coverage, pharmacy contracts, deductibles, and substitution rules.
Does Bactrim DS have biosimilar competition?
No. Bactrim DS is a small-molecule chemical drug, not a biologic. It competes with generic equivalents approved through the ANDA pathway rather than biosimilars.
Can a pharmacy substitute generic sulfamethoxazole/trimethoprim for Bactrim DS?
In most U.S. dispensing situations, an approved generic equivalent may be substituted subject to state law, prescriber instructions, payer rules, and product availability.
What is the largest long-term threat to Bactrim DS demand?
The largest structural threats are antimicrobial resistance and substitution by other antibiotics, particularly in uncomplicated urinary tract infections and skin infections where guideline preferences and susceptibility patterns can change.
References
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Centers for Disease Control and Prevention. (2024). Antibiotic resistance threats in the United States. U.S. Department of Health and Human Services.
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Gupta, K., Hooton, T. M., Naber, K. G., Wullt, B., Colgan, R., Miller, L. G., Moran, G. J., Nicolle, L. E., Raz, R., Schaeffer, A. J., & Soper, D. E. (2011). International clinical practice guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women. Clinical Infectious Diseases, 52(5), e103-e120.
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National Institutes of Health. (2024). Guidelines for the prevention and treatment of opportunistic infections in adults and adolescents with HIV: Pneumocystis pneumonia. U.S. Department of Health and Human Services.
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U.S. Food and Drug Administration. (2023). BACTRIM and BACTRIM DS prescribing information. U.S. Department of Health and Human Services.
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U.S. Food and Drug Administration. (2024a). Approved drug products with therapeutic equivalence evaluations: Orange Book. U.S. Department of Health and Human Services.
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U.S. Food and Drug Administration. (2024b). Drugs@FDA and Approved Drug Products database. U.S. Department of Health and Human Services.
