Trimethoprim*

Trimethoprim/sulfamethoxazole (TMP/SMX)

Infections caused by susceptible bacteria that are resistant to other antibiotics, including methicillin-resistant Staphylococcus aureus (MRSA Methicillin-resistant Staphylococcus aureus (MRSA) Staphylococcus aureus is the most dangerous of all of the many common staphylococcal bacteria. These gram-positive, sphere-shaped (coccal) bacteria (see figure How Bacteria Shape Up) often cause... read more )

Chronic infection of the prostate (prostatitis Prostatitis Prostatitis is pain and swelling, inflammation, or both of the prostate gland. The cause is sometimes a bacterial infection. Pain can occur in the area between the scrotum and anus or in the... read more )

Bladder infections in women

Prevention of recurring urinary tract infections (UTIs) Overview of Urinary Tract Infections (UTIs) In healthy people, urine in the bladder is sterile—no bacteria or other infectious organisms are present. The tube that carries urine from the bladder out of the body (urethra) contains no bacteria... read more in women Overview of Urinary Tract Infections (UTIs) In healthy people, urine in the bladder is sterile—no bacteria or other infectious organisms are present. The tube that carries urine from the bladder out of the body (urethra) contains no bacteria... read more and children Treatment A urinary tract infection is a bacterial infection of the urinary bladder (cystitis), the kidneys (pyelonephritis), or both. Urinary tract infections are caused by bacteria. Infants and younger... read more

Intestinal infections due to various bacteria, such as Escherichia coli Escherichia coli Infections Escherichia coli (E. coli) are a group of gram-negative bacteria that normally reside in the intestine of healthy people, but some strains can cause infection in the digestive tract, urinary... read more (E. coli)

Treatment and prevention of pneumonia due to Pneumocystis jirovecii Causes Pneumonia is infection of the lungs. Pneumonia in people whose immune system is weakened or impaired (for example, by acquired immunodeficiency syndrome [AIDS], cancer, organ transplantation... read more (a fungus)

Nausea, vomiting, and diarrhea

Allergy Allergies to Drugs People sometimes mistake many adverse drug reactions for allergies. For example, people who experience stomach discomfort after taking aspirin (a common adverse reaction) often say they are... read more (including rashes)

Crystals in urine (rare)

A decrease in white blood cell and platelet counts

Sensitivity to sunlight

Possibly increased tendency to bleed if used with warfarin

Kidney failure in people who have kidneys that are not functioning well