This page contains brief details about the drug , it's indication, dosage & administaration, mechanism of action, related brands with strength, warnings and common side effects.

Background and Date of Approval

The U.S. FDA-approved Sulfamethoxazole + Trimethoprim for bacterial infection on June 26, 2001. Sulfamethoxazole + Trimethoprim belongs to the medication class known as an Anti-infective, which inhibits the production of Folic acid in bacteria. 

Mechanism of Action of undefined

Sulfamethoxazole, Trimethoprim inhibits the production of Folic acid in bacteria which is essential for the growth and multiplication of bacteria and produces an antibacterial effect.

Uses of undefined

Sulfamethoxazole + Trimethoprim treats various bacterial infections such as It treats various bacterial infections, including pneumonia, bronchitis, urinary tract infections, ear infections, and abdominal infections. 

undefined Drug administaration and Dosage available

Take the Sulfamethoxazole + Trimethoprim as your physician advises. Usually, the tablets will be taken with or without food. Do not crush, chew, or open the medicine. Your physician will decide the correct dosage and duration based on age, body weight, and disease condition. Only stop taking the tablet if your doctor advises you to stop.

Warnings, Precautions and Side Effects of undefined


This medicine should not be consumed if you are allergic to Sulfamethoxazole + Trimethoprim or any of its ingredients in the medication. Also, it is contraindicated for individuals with severe liver or kidney problems and infants within the first six weeks of life. Inform your doctor if you have a history of blood disorders that increase the risk of bleeding or bruising (thrombocytopenia) or the rare blood disorder known as porphyria. Do not get pregnant or breastfeed during the treatment. Talk to your doctor for more information. Before starting the treatment, inform your doctor if you have a bacterial infection (group A beta-hemolytic streptococci infection), severe hyperkalemia (serum or plasma potassium level), or risk of hyponatremia (abnormally low levels of sodium in the blood). This medicine is not advised to use in children under 12 years old. 


Notify your doctor if you are pregnant, planning to get pregnant, or think you may be pregnant or breastfeeding. Before taking Sulfamethoxazole + Trimethoprim, inform your doctor if you are experiencing severe skin rash or blood disorders, have a history of allergies or asthma, insufficient folic acid levels, glucose-6-phosphate dehydrogenase deficiency (a genetic disorder that affects red blood cells), phenylketonuria (inherited disorder). It is advised to check regular blood counts. 

Side Effects

The most common side effects of Sulfamethoxazole + Trimethoprim are sleepiness, trouble concentrating, dry mouth, dizziness, increase in appetite, drowsiness, and headache. Serious side effects while taking Sulfamethoxazole + Trimethoprim are serious allergic reactions (swelling of the mouth, lips, gums, throat, tongue, troubled breathing, rash, raised bumps, and blisters), sudden changes in mood, behaviors, thoughts, or feelings, swelling of hands, feet, and legs, weight gain, muscle problems, muscle pain, soreness, or weakness, problems with eyesight, including blurry vision.

Word Of Advice

Liver, heart, and kidney patients should take Sulfamethoxazole + Trimethoprim cautiously and inform their doctor about all the underlying medical conditions. Do not stop the medicine until your doctor advises. Do not double-dose the medicine to make up for a forgotten dose. Do not breastfeed while taking Sulfamethoxazole + Trimethoprim unless your doctor advises. 

Notify your doctor if you experience any serious side effects. Your medical professional will inform you if you need any dose adjustments. Contact your doctor for more information. Keep out of sight and reach of pets and children. Do not freeze the medicine. Do not store above 30°C. Always check the expiry date before consuming it.

Frequently Asked Question


  1. KD Tripathi, Essentials of Medical Pharmacology, Sulfonamides, Cotrimoxazole, and Quinolones, 7th edition, 2013, 706-708.
  2. Goodman & Gilman’s, The Pharmacological Basis of Therapeutics, Sulfonamides, Trimethoprim-Sulfamethoxazole, Quinolones, and Agents for urinary tract infections, 12th edition, 2011, 1468-1470.
  3. Tillomed Laboratories Ltd, Electronic medicines compendium (emc), [ Revised on Feb 2023] [ Accessed on 20th June 2023], pil.11466.pdf (
  4. AR Scientific, Inc, US Food and Drug Administration, [ Revised on June 2010] [ Accessed on 20th June 2023,


The drug information on this page is not a substitute for medical advice. It is meant for educational purposes only. For further details, consult your doctor about your medical condition to know if you are eligible to receive this treatment.