- Bacterial Infections 101 Pictures Slideshow
- Take the Tummy Trouble Quiz
- Hepatitis C Slideshow Pictures
- What is sulfamethoxazole, and how does it work (mechanism of action)?
- Is sulfamethoxazole available as a generic drug?
- Do I need a prescription for sulfamethoxazole?
- What are the side effects of sulfamethoxazole?
- What is the dosage for sulfamethoxazole?
- Which drugs or supplements interact with sulfamethoxazole?
- Is sulfamethoxazole safe to take if I'm pregnant or breastfeeding?
- What else should I know about sulfamethoxazole?
What is sulfamethoxazole, and how does it work (mechanism of action)?
Sulfamethoxazole is an anti- bacterial sulfonamide. It prevents the formation of dihydrofolic acid, a compound that bacteria must be able to make in order to survive. Although it was once a very useful antibiotic, it is almost obsolete as a single agent today due to the development of bacterial resistance to its effects. Sulfamethoxazole is now used primarily in combination with trimethoprim, a combination product known as Bactrim or Septra. Sulfamethoxazole was approved by the FDA in 1961. According to the FDA database, all brand and generic formulations of sulfamethoxazole have been discontinued.
What are the side effects of sulfamethoxazole?
: Common side effects of sulfamethoxazole are:
Sulfamethoxazole should be stopped at the first appearance of a skin rash since the rash may become severe. Serious rashes include Stevens-Johnson syndrome (aching joints and muscles; redness, blistering, and peeling of the skin); toxic epidermal necrolysis (difficulty in swallowing; peeling, redness, loosening, and blistering of the skin). Sulfamethoxazole therapy also can cause extensive sunburn, following exposure to sunlight. Patients receiving sulfamethoxazole should avoid excessive exposure to sunlight and should wear sunscreen.
Other important rare side effects include:
Sulfamethoxazole may form crystals in the urine which may damage the kidney and cause bleeding into the urine. It is important to drink additional liquids during sulfonamide therapy to prevent these side effects.
What is the dosage for sulfamethoxazole?
Sulfamethoxazole usually is taken two or three times daily, with or without meals. It should be taken with 6 to 8 ounces of liquid to prevent crystals from forming in the urine. Persons with advanced kidney diseases may require lower doses.
Which drugs or supplements interact with sulfamethoxazole?
Sulfamethoxazole can enhance the blood-thinning effects of warfarin (Coumadin), possibly leading to bleeding. Sulfonamides such as sulfamethoxazole can increase the metabolism (break-down and elimination) of cyclosporine (causing loss of effectiveness of cyclosporine), and can add to the kidney damage caused by cyclosporine. All sulfonamides can crystallize in urine when the urine is acidic. Since methenamine (Hiprex, Urex, Mandelamine) causes an acidic urine, it should not be used with sulfonamides.
Is sulfamethoxazole safe to take if I'm pregnant or breastfeeding?
The effects of the sulfonamide class of antibiotics on the fetus have not been adequately studied. Therefore, physicians may use them if the benefits are deemed to outweigh potential risks. On the other hand, use of sulfonamides near term (that is, near the ninth month of pregnancy) may cause bilirubin to be displaced from proteins in the infant's blood. Displacement of bilirubin can lead to a dangerous condition called kernicterus in which the bilirubin damages the brain. For this reason, sulfonamides should not be used near term birth.
What else should I know about sulfamethoxazole?
What preparations of sulfamethoxazole are available?
Tablets: 500 mg and 1 gm.
How should I keep sulfamethoxazole stored?
The tablets should be kept at room temperature, 15 C - 30 C (59 F - 86 F).
Quick GuideSymptoms of Mono: Infectious Mononucleosis Treatment
Sulfamethoxazole (Gantanol, Gantanol DS) is an antibiotic prescribed for the treatment of malaria, pinkeye due to chlamydia, toxoplasmosis, and urinary tract infections. According to the FDA database, all brand and generic formulations of sulfamethoxazole have been discontinued. Side effects, drug interactions, warnings and precautions, and patient safety information should be reviewed prior to taking any medication.
Multimedia: Slideshows, Images & Quizzes
MRSA Quiz: Infection Symptoms & Treatment
It's the MRSA Quiz! For the carriers among us, you'd be surprised that the infectious superbug is lurking on this body part! Take...
Do I Have Pneumonia? Symptoms & Signs
Pneumonia can be deadly. Take the Pneumonia Quiz on MedicineNet to learn more about this highly contagious, infectious disease....
Picture of Bacterial Conjunctivitis (Pink Eye)
Pink eye, or conjunctivitis, is redness and inflammation of the membranes (conjuctiva) covering the whites of the eyes and the...
Related Disease Conditions
Malaria is a disease that is spread by the bite of an infected Anopheles mosquito. Malaria symptoms include fever, chills,...
Pinkeye, also called conjunctivitis, is redness or irritation of the conjunctivae, the membranes on the inner part of the eyelids...
Sexually Transmitted Diseases in Women (STD)
Sexually transmitted diseases (STDs) are among the most common infectious diseases in the United States. STDs can be spread...
Urinary Tract Infections (UTIs)
A urinary tract infection (UTI) is an infection of the bladder, kidneys, ureters, or urethra. E. coli, a type of bacteria that...
Whooping Cough (Pertussis)
Whooping cough (pertussis) is highly contagious respiratory infection that is caused by the bacteria Bordetella pertussis. There...
Chlamydia in Women (Symptoms and Cures)
Chlamydia is the most common sexually transmitted disease in the U.S. Signs and symptoms of chlamydia, a bacterial infection,...
Toxoplasmosis (toxo) is a parasitic infection that causes flu-like symptoms, swollen lymph nodes, and muscle aches and pains that...
STDs in Men
Sexually transmitted diseases (STDs) are infections transmitted during sexual contact. They may be caused by viruses, bacteria,...
Treatment & Diagnosis
- Pneumonia FAQs
- MRSA FAQs
- Medication Disposal
- Dangers of Mixing Medications
- How To Reduce Your Medication Costs
- Pharmacy Visit, How To Get The Most Out of Your Visit
- Indications for Drugs: Approved vs. Non-approved
- Drugs: Buying Prescription Drugs Online Safely
- Drugs: The Most Common Medication Errors
- Generic Drugs, Are They as Good as Brand-Names?
Medications & Supplements
Prevention & Wellness
Infectious Disease Resources
Health Solutions From Our Sponsors
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.