What it's used for
Sulfamethoxazole and trimethoprim is used to treat or prevent infections proven or strongly suspected to be caused by susceptible bacteria.
Source: U.S. FDA-approved prescribing information (openFDA).
Typical dosing
For urinary tract infections in adults, the usual dosage is 1 double-strength tablet or 2 regular tablets every 12 hours for 10 to 14 days, and it is contraindicated in children under 2 months old.
Dosing shown here is the general FDA-labeled range. Your prescribing clinician determines the exact dose, form, and schedule for you — this is not a substitute for medical advice.
Boxed warning / key safety info
Exposure to this medication during pregnancy may be associated with an increased risk of congenital malformations.
Common side effects
The most common side effects include gastrointestinal disturbances like nausea and vomiting, as well as allergic skin reactions such as rash and hives.
Covered strengths on the Tab $0 list
Covered at $0 with an active Tab membership when filled at a participating pharmacy nationwide or through mail order. A licensed clinician must prescribe the medication.
Related medications
Other antibiotics & antivirals medications covered at $0 with an active Tab membership.
Sulfamethoxazole/Trimethoprim cost without insurance
Cash prices for Sulfamethoxazole/Trimethoprim without insurance vary widely by pharmacy, strength and quantity — the same prescription can cost very different amounts at two pharmacies in the same town. That is the problem a membership solves.
Sulfamethoxazole/Trimethoprim is on Tab's covered $0 generic list. With an active Tab membership, every covered strength is $0 — not a percentage off, not a coupon that changes month to month — at participating pharmacies nationwide or through mail order. You do not need insurance, and Tab works whether or not you have a health plan.
Tab is a membership, not insurance. Covered medications require a prescription from a licensed clinician.
Sulfamethoxazole/Trimethoprim dosage and administration
Sulfamethoxazole and trimethoprim tablets are contraindicated in pediatric patients less than 2 months of age. Urinary Tract Infections and Shigellosis in Adults and Pediatric Patients, and Acute Otitis Media in Children Adults: The usual adult dosage in the treatment of urinary tract infections is 1 sulfamethoxazole and trimethoprim DS (double strength) tablet or 2 sulfamethoxazole and trimethoprim tablets every 12 hours for 10 to 14 days. An identical daily dosage is used for 5 days in the treatment of shigellosis. Children: The recommended dose for children with urinary tract infections or acute otitis media is 40 mg/kg sulfamethoxazole and 8 mg/kg trimethoprim per 24 hours, given in two divided doses every 12 hours for 10 days. An identical daily dosage is used for 5 days in the treatment of shigellosis.
Excerpt from the FDA-approved prescribing information (openFDA), retrieved 2026-09-15. Your prescribing clinician decides the exact dose, form and schedule for you — this is not medical advice.
Sulfamethoxazole/Trimethoprim side effects
The most common adverse effects are gastrointestinal disturbances (nausea, vomiting, anorexia) and allergic skin reactions (such as rash and urticaria). FATALITIES ASSOCIATED WITH THE ADMINISTRATION OF SULFONAMIDES, ALTHOUGH RARE, HAVE OCCURRED DUE TO SEVERE REACTIONS, INCLUDING STEVENS-JOHNSON SYNDROME, TOXIC EPIDERMAL NECROLYSIS, FULMINANT HEPATIC NECROSIS, AGRANULOCYTOSIS, APLASTIC ANEMIA AND OTHER BLOOD DYSCRASIAS (SEE WARNINGS SECTION). Hematologic : Agranulocytosis, aplastic anemia, thrombocytopenia, leukopenia, neutropenia, hemolytic anemia, megaloblastic anemia, hypoprothrombinemia, methemoglobinemia, eosinophilia.
Excerpt from the FDA-approved prescribing information (openFDA), retrieved 2026-09-15. This is not a complete list. Report side effects to your clinician, and seek care for anything severe or unexpected.
Who should not take sulfamethoxazole/trimethoprim
Sulfamethoxazole and trimethoprim is contraindicated in patients with a known hypersensitivity to trimethoprim or sulfonamides, in patients with a history of drug-induced immune thrombocytopenia with use of trimethoprim and/or sulfonamides, and in patients with documented megaloblastic anemia due to folate deficiency. Sulfamethoxazole and trimethoprim is contraindicated in pediatric patients less than 2 months of age. Sulfamethoxazole and trimethoprim is also contraindicated in patients with marked hepatic damage or with severe renal insufficiency when renal function status cannot be monitored.
Excerpt from the FDA-approved prescribing information (openFDA), retrieved 2026-09-15. Whether this medication is appropriate for you is a clinical decision made by your prescribing clinician.
Common questions
Is sulfamethoxazole/Trimethoprim covered at $0 with Tab?
Yes. Sulfamethoxazole/Trimethoprim is on Tab's covered $0 generic list — every covered strength is $0 with an active membership, at participating pharmacies nationwide or by mail order.
Do I need insurance to get sulfamethoxazole/Trimethoprim through Tab?
No. Tab is a membership, not insurance. Covered medications are $0 with an active membership whether or not you have a health plan.
How do I get a sulfamethoxazole/Trimethoprim prescription with Tab?
Book a video visit with a licensed Tab clinician (unlimited visits are included with membership). If it's clinically appropriate, they send the prescription to your chosen participating pharmacy or by mail order.
How much does sulfamethoxazole/trimethoprim cost without insurance?
Without insurance, retail cash prices for sulfamethoxazole/trimethoprim vary by pharmacy, strength and quantity. Sulfamethoxazole/Trimethoprim is on Tab's covered $0 generic list, so every covered strength is $0 with an active Tab membership at participating pharmacies nationwide or by mail order.
What is the cheapest way to get sulfamethoxazole/trimethoprim?
For medications on Tab's covered list, a Tab membership is the cheapest route: covered strengths of sulfamethoxazole/trimethoprim are $0 with an active membership, and unlimited video visits with a licensed clinician are included, so the visit that produces the prescription is covered too.
What is the usual dose of sulfamethoxazole/trimethoprim?
Sulfamethoxazole and trimethoprim tablets are contraindicated in pediatric patients less than 2 months of age. (FDA-approved label, retrieved 2026-09-15. Your clinician sets your dose.)
What are the side effects of sulfamethoxazole/trimethoprim?
The most common adverse effects are gastrointestinal disturbances (nausea, vomiting, anorexia) and allergic skin reactions (such as rash and urticaria). (FDA-approved label, retrieved 2026-09-15.)
Sulfamethoxazole/Trimethoprim is $0 on the covered list
Members pay $0 for covered generics at participating pharmacies nationwide or by mail order — plus unlimited virtual primary care, urgent care and dermatology visits. No insurance needed.
Solo $49/mo · Family $119/mo for up to 4 people · Family+ $149/mo for up to 8
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