Uncomplicated urinary tract infections (your garden variety cystitis) is a common ED diagnosis. For most patients there is a wide variety of potentially effective treatment options. The purpose of this post is to caution you against the use of fluoroquinolones (like ciprofloxacin) to treat uncomplicated UTIs in children.

Why is this the case? Well, fluoroquinolones are known to be one of the best options for treating Pseudomonas aeruginosa. But resistance is also an emerging problem. In fact, per Zervos et al, rampant use in adults has increased resistance prevalence. In fact, Fridkin et al noted that resistant P. aeruginosa is #2 only to MRSA in the US. Fluoroquinolone resistant species can also spread from person to person in the community, which is where you will be sending patients with uncomplicated UTI. To make matters worse, cross-resistance to Streptococcus pneumoniae, E. coli, Neisseria, Salmonella and Mycobacterium may develop as well if we keep using Cipro. Additionally, MIC concentrations seem to be increasing significantly – thus requiring more drug to kill the same bacteria. There’s also the issue of tendon rupture. Fortunately (or unfortunately depending on how you look at it) that is more of an issue for our canine friends… So right now approved indications for systemic fluoroquinolone use in kids is limited to Ciprofloxacin for complicated urinary tract infections, pyelonephritis, and inhalational anthrax.

OK, we got it, don’t prescribe Cipro… So now what?

Fortunately, there are a lot of great options out there. Let me highlight four.

Nitrofurantoin

Infants >1 month and Children: 5-7 mg/kg/day divided every 6 hours; maximum dose: 400 mg/day

Children >12 years: 100 mg every 12 hours for 7 days

Great agent, because it really doesn’t concentrate outside of the urinary tract. This does mean however, that it doesn’t concentrate in the blood, and thus can’t penetrate tissues well. It is for that reason that Nitrofurantoin is not a good choice for pyelo. So, in kids with febrile UTIs in which you can’t rule out pyelo – don’t use it.

Trimethoprim/Sulfamethoxazole

Infants and Children 2-24 months: 6-12 mg TMP/kg/day in divided doses every 12 hours for 7-14 days

Children >24 months and Adolescents: 8 mg TMP/kg/day in divided doses every 12 hours for 3 days; longer duration may be required in some patients; maximum single dose: 160 mg TMP

Another good choice – as long as you don’t have a high prevalence of resistance in your area. You must also consider a potential history of sulfa allergies.

Amoxicillin/Clavulante

Infants and Children 2-24 months: 20-40 mg/kg/day in divided doses 3 times daily using the 125 mg/5 mL or 250 mg/5 mL oral suspension; maximum single dose: 500 mg amoxicillin (AAP, 2011)

Again, an example of scaling your drug to the bacteria at hand (on in this case in the bladder)

Cephalexin

Children: 25-50 mg/kg/day divided every 6-8 hours; severe infections: 50-100 mg/kg/day divided every 6-8 hours; maximum dose: 4 g/day

Children >15 years: 500 mg every 12 hours for 7-14 days

Just like Nitorfurantoin, cephalexin can concentrate in high levels in the bladder. It can be a surprisingly good choice.

To learn more about this topic on the adult side I recommend you check out the two-parter over at Academic Life in Emergency Medicine (Part 1 and Part 2) on the treatment of uncomplicated UTI in older adults. Pediatricians need not apply.