“My child is on Sulfatrim.  I need some info, please?!”  emailed to us by concerned mama.

Here ya go 🙂

Trimethoprim-sulfamethoxazole (Bactrim, Septra, Sulfatrim) is a sulfa antibiotic combo that has been around since the 1960s. It is used in kids most commonly to treat urinary tract infections (UTIs), otitis media, chronic bronchitis, acne and typhoid fever.

Bactrim belongs to the class of drugs called sulfonamides. Bactrim is the most well-known of the group. Others include dapsone (Alczone), sulfadiazine and sulfasalazine (Azulfidine). These are the antibiotics that should be avoided if your child has a sulfa allergy.

Bactrim is available in IV formula, oral suspension (Sulfatrim) and tablets. It is approved for kids 2 months and older. Bactrim is dosed on the trimethoprim portion of the combo. Typical dosing for treating kids ranges from 6-20mg trimethoprim/kg divided into two to four doses a day. Dosing for UTI prophylaxis 2mg trimethoprim/kg once daily or 5mg/kg twice weekly.

Bactrim has an interesting way of fighting bacteria. It uses sequential inhibition. Which means it inhibits two enzymes necessary in the step by step process for bacteria to make folic acid. The sulfamethoxazole inhibits the first enzyme and the trimethoprim inhibits the second. Alone these antibiotics would be bacteriostatic but together they can actually kill the bacteria. On occasion, when taken for a prolonged period of time, this can actually decrease folic acid in humans.  However, this is rare for two reasons –human folic acid enzymes are less sensitive to Bactrim and humans can ingest folic acid.

Common side effects include belly upset, diarrhea, lack of appetite, headache, dry eyes and bladder stones. There are more serious side effects, mostly associated with an allergic reaction – the dreaded sulfa allergy.  An allergic reaction can create joint swelling and liver and kidney issues. Bactrim can also cause Stevens-Johnson syndrome, which includes a blistering rash and flu-like symptoms. Stevens-Johnson syndrome is scary but extremely rare with only about 300 new cases in the States a year and mostly in adult women. To avoid these severe side effects, Bactrim should not be given to patients with a known sulfa allergy or G-6-PD deficiency. If the child develops problems breathing or a rash, stop the antibiotic right away.

If taking the suspension, it can be stored at room temperature.  Be sure to shake the suspension well before giving dose. If taking the tablets, drink it with a full glass of water to avoid the risk of bladder stones. The medicine can be taken with food if it causes belly upset. Bactrim can interact with quite a few other medications, so check with your child’s physician or pharmacist.

Bactrim is available in generic so it is reasonably priced. It is a good first line choice for treatment of UTIs and a great option for kids with an allergy to penicillins.

Whadyathink?  Please leave a comment/question!