Healthy Living

What Does Bactrim Treat?

What Does Bactrim Treat


Bactrim is a combination of antibiotics called trimethoprim and sulfamethoxazole, which help treat different types of bacterial infections. Bactrim can be used for the treatment of urinary tract infections (UTIs), ear infections, bronchitis, shigellosis, traveler's diarrhea, and Pneumocystis pneumonia (PCP).

  • Sulfamethoxazole - This antibiotic is very effective against gram-positive and gram-negative bacteria.  Sulfamethoxazole can be given alone or in combination with other antibiotics. This drug is commonly used to treat bacterial infections in the urinary and respiratory tract. 
  • Trimethoprim - This drug is used to treat middle ear infections, traveler’s diarrhea, and bladder infections. 

What conditions does Bactrim treat?

Bactrim can treat a wide variety of conditions. This antibiotic can be used for the treatment of the following conditions:

  • Chronic bronchitis caused by Streptococcus pneumoniae and Haemophilus influenzae
  • Middle ear infection caused by Streptococcus and Haemophilus influenzae
  • Intestinal infections caused by Shigella 
  • Short-term diarrhea
  • Diverticulitis
  • Whipple's Disease
  • Urinary tract infections caused by Klebsiella, Morganella morganii, Proteus organisms, Enterobacter cloacae, or E. coli
  • UTI prevention
  • Prevention of plague 
  • Toxoplasmosis prevention
  • AIDS with toxoplasmosis
  • Pneumocystis jirovecii pneumonia and its prevention
  • Bacterial pneumonia
  • Whooping Cough
  • Sinus irritation and congestion
  • Bone and skin infections
  • Typhoid Fever
  • Sexually transmitted disease (STD) due to Chlamydia
  • Chronic bacterial prostatitis
  • Salmonella paratyphi infection
  • Coxiella burnetii infection
  • Nocardia infection
  • Colonization with Menigococcus without symptoms of infection
  • Diabetic foot infection
  • Chronic fungal infections
  • Brucellosis 
  • CNS infection with Listeria monocytogenes
  • Bacterial endocarditis
  • Vibrio cholerae infection
  • Chronic granulomatous disease (CGD)

How does Bactrim work?

In 1973, Bactrim was approved by the FDA. Bactrim consists of two antibiotics: sulfamethoxazole and trimethoprim. Bacteria need folic acid to grow, and these two synthetic antibiotics impair the ability of bacteria to utilize folic acid. Sulfamethoxazole is a sulfa drug, which can interrupt dihydrofolic acid production. Trimethoprim, on the other hand, disrupts tetrahydrofolic acid production. These forms of folic acid are needed by human cells and bacteria for the production of proteins. Trimethoprim interrupts tetrahydrofolic acid production by disabling the enzyme that is responsible for the production of tetrahydrofolic acid from dihydrofolic acid.

The combination of sulfamethoxazole and trimethoprim inhibits bacterial protein production. Such antibiotic combination is also more effective than using each drug alone. 

Bactrim and Alcohol

Alcohol and Bactrim may cause certain side effects, such as drowsiness, stomach upset, and dizziness. The severity of the side effects also increases when alcohol is consumed. Other side effects may include:

  • Headache
  • Flushing
  • Nausea
  • Vomiting
  • Rapid heart rate

When buying products, always check their labels if they contain some amount of alcohol to avoid experiencing side effects. Examples of products are mouthwashes and cold medicines. Moreover, alcohol taken in moderate amounts also reduces or delays the recovery time of people. 


Most adults with urinary tract infections are treated with one double-strength tablet or two single strength tablets twice a day for 10-14 days. Flare-ups of chronic bronchitis symptoms are often treated using the same treatment regimen for two weeks. 

This antibiotic should also be taken with 6-8 ounces of liquid to avoid the formation of crystals in the urine. People with advanced kidney damage may need a lower dosage. 

Side Effects of Bactrim 

Some of the side effects of sulfamethoxazole/trimethoprim may not require medical attention since they may resolve on their own as the body adjusts to the medicine. Healthcare providers may also inform you on how to reduce or prevent the drug's side effects. Speak with your doctor if you continue to experience the following common side effects:

Nausea and Vomiting

Initially, the drug causes nausea and vomiting, but as the body adjusts with the medication, these side effects also go away. Stomach discomfort can be reduced if Bactrim is taken with food. Consuming a bland diet may also help relieve gastrointestinal discomfort along with avoiding the consumption of fatty and spicy foods. 

Vaginal Infection

A vaginal infection may develop in some women who have taken Bactrim DS since the level of good bacteria in the body tends to decrease when antibiotics are taken. However, this infection can be prevented in many ways, such as the daily supplementation of probiotics or including foods high in probiotics in the diet. 

The symptoms that are associated with vaginal infection include increased vaginal discharge, redness and burning sensation in the vagina, and itching after sexual intercourse. Consult a gynecologist to undergo vaginal examination and to have proper diagnosis and treatment for your condition. 

Increased Sensitivity to Sunlight

An increased sensitivity to sunlight may be experienced by people who take Bactrim DS. Such people may also easily develop sunburn. If you are taking this medication, and you are not sure how this medication will affect you, then make sure that you avoid direct sunlight and do not spend much time in tanning beds and sunlamps. To prevent sunburn, it is important to use clothes that will protect you. You can also use sunblocks.


People who are taking Bactrim and experience insomnia should consult a doctor. A sleep aid may be prescribed for people who have insomnia while being treated with Bactrim. 

Possible Interactions 

Aside from alcohol, Bactrim can also have possible interactions with the following:

  • Nervous system medications such as Dilantin 
  • Antidepressants and other mood stabilizers
  • Drugs that suppress the immune system
  • Blood pressure drugs
  • Nonsteroidal anti-inflammatory drugs (NSAIDs)

Consuming alcohol while taking Bactrim can lead to serious reactions. The risk of developing serious reactions are often increased when people have kidney disease. The combination of Bactrim and alcohol is dangerous since Bactrim interacts with acetaldehyde dehydrogenase, an enzyme that breaks down alcohol in the body for metabolism. When Bactrim and alcohol are mixed, acetaldehyde tends to accumulate, which then leads to breathing problems, headache, flushing, and nausea. 

The same reaction may also occur when Antabuse is taken along with alcohol. Antabuse is a drug that is specifically used to treat alcoholism. People with impaired liver or kidney function as well as folate deficiency should be cautious when taking Bactrim. 

Bactrim Safety

Bactrim is a combination antibiotic, and an effective one. However, it may not be recommended for people who have problems with their liver, kidney, or folate levels. The risk of Bactrim side effects may also increase in older people.

Bactrim is also not suitable for nursing mothers and children under the age of two months. Before taking this antibiotic, pregnant women should exercise caution. Bactrim should not be taken by those who are allergic to drugs, such as thiazide diuretics, diabetes medications, and sulfa drugs.