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Sulfamethoxazole; Trimethoprim



What is sulfamethoxazole?

What is sulfamethoxazole? Sulfamethoxazole 800 mg is a combination of two antibiotics sulfamethoxazole and trimethoprim. Sulfamethoxazole is used for treating a wide variety of bacterial infections (such as middle ear, urine, respiratory, and intestinal infections). Moreover, It is also used to prevent and treat a certain type of pneumonia (pneumocystis-type). Sulfamethoxazole trimethoprim dose should not be used in children less than 2 months of age due to the risk of serious side effects.

Sulfamethoxazole is used for treating only certain types of infections. It will not work for viral infections (such as flu). Unnecessary use or misuse of any antibiotic can lead to its decreased effectiveness.

How to use Sulfamethoxazole 800 mg

  • Take Sulfamethoxazole trimethoprim dose by mouth, as directed by your doctor with a full glass of water (8 ounces / 240 milliliters).
  • If a stomach upset occurs, take it with food or milk.
  • Drink plenty of fluids while taking this medication to lower the unlikely risk of kidney stones forming, unless your doctor advises you otherwise.
  • Dosage is based on your medical condition and response to treatment.

For the best effect, take this antibiotic at evenly spaced times. To help you remember, take this medication at the same time(s) every day. Moreover, If you have any questions about what sulfamethoxazole is used for? ask your doctor.

Continue to take the Sulfamethoxazole trimethoprim dose until the full prescribed amount is finished, even if symptoms disappear after a few days. Stopping it too early may allow bacteria to continue to grow, which may result in a relapse of the infection.

Tell your doctor if your condition persists or worsens.

Side effects

  • Nausea
  • vomiting
  • diarrhea
  • loss of appetite

However, If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including

  • muscle weakness
  • mental/mood changes
  • signs of kidney problems
  • extreme drowsiness
  • signs of low blood sugar

Get medical help right away if you have any very serious side effects, including

  • persistent headache
  • neck stiffness
  • seizures
  • slow/irregular heartbeat
Some rare and serious side effects

Sulfamethoxazole 800 mg may rarely cause serious (possibly fatal) allergic reactions and other side effects such as

  • severe peeling skin rash
  • blood disorders
  • liver damage
  • lung injury.

If you notice any of the following, get medical help right away:

  • skin rash/blisters
  • itching/swelling
  • persistent sore throat or fever
  • paleness
  • joint pain/aches
  • persistent cough
  • trouble breathing
  • easy bleeding/bruising
  • yellowing eyes or skin
  • persistent nausea/vomiting
  • unusual fatigue
  • dark urine

Sulfamethoxazole trimethoprim dose may rarely cause a severe intestinal condition (Clostridium difficile-associated diarrhea) due to a type of resistant bacteria. However, This condition may occur during treatment or weeks to months after treatment has stopped. Tell your doctor right away if you develop: persistent diarrhea, abdominal or stomach pain/cramping, blood/mucus in your stool.

Do not use anti-diarrhea or opioid medications if you have any of these symptoms because these products may make them worse.

Use of this medication for prolonged or repeated periods may result in oral thrush or a new yeast infection. Contact your doctor if you notice white patches in your mouth, a change in vaginal discharge, or other new symptoms.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

Warnings & Precautions

  1. Before taking sulfamethoxazole with trimethoprim, tell your doctor or pharmacist if you are allergic to sulfa medications or trimethoprim.
  2. Before using the Sulfamethoxazole trimethoprim dose, tell your doctor or pharmacist your medical history.
  3. Do not have any immunizations/vaccinations while using this medication unless your doctor tells you to.
  4. Before having surgery, tell your doctor or dentist about all the products you use.
  5. Limit your time in the sun.

If you have diabetes, Sulfamethoxazole 800 mg may affect your blood sugar. Check your blood sugar regularly as directed and share the results with your doctor. Tell your doctor right away if you have symptoms of low blood sugar. Your doctor may need to adjust your diabetes medication, exercise program, or diet.

Older adults may be more sensitive to the side effects of this drug, especially skin reactions, blood disorders, easy bleeding/bruising, and a high potassium blood level.

Patients with AIDS may be more sensitive to the side effects of this drug, especially skin reactions, fever, and blood disorders.

Sulfamethoxazole 800 mg is not recommended for use during pregnancy especially near the expected delivery date because of possible harm to the unborn baby. Consult your doctor for more details.

Sulfamethoxazole trimethoprim dose passes into breast milk. While there have been no reports of harm to healthy infants, this drug may have undesirable effects on infants who are ill or premature or have certain disorders (jaundice, high blood levels of bilirubin, G6PD deficiency). Consult your doctor before breastfeeding.


Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

Drug interactions

Drug interactions may change how your medications work or increase your risk for serious side effects. Moreover, This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Moreover, Do not start, stop, or change the dosage of any medicines without your doctor’s approval.

Some products that may interact with this drug include: “blood thinners” (such as warfarin), dofetilide, methenamine, methotrexate.

What is Canada Drugs’ online pharmacy?

Sulfamethoxazole 800 mg with or without a prescription from us. Moreover, Consult your doctor if you have been exposed to an infection or for more details.

For the safety and health of our clients, Canada Drugs employs dedicated, professional certified pharmacists to guarantee that every order is examined before it is dispensed. Your health is our main priority at



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