Pediatric Imperforate Anus (Anorectal Malformation) Medication

Updated: Dec 30, 2019
  • Author: Nelson G Rosen, MD, FACS, FAAP; Chief Editor: Carmen Cuffari, MD  more...
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Medication Summary

Many children with anorectal malformations require medications for various reasons. Beyond perioperative medications, maintenance medications often include urinary antibiotic prophylaxis or treatment and/or laxatives.

Urinary prophylaxis is used to mitigate the risk of urinary infection and urosepsis in children with risk factors for urinary infection such as urinary fistula, vesicoureteral reflux, or continent diversion. Common agents include oral amoxicillin, oral trimethoprim/sulfamethoxazole, and gentamicin bladder irrigations. Comprehensive information on all these medications and others is available in the eMedicine pediatric topic Urinary Tract Infection.

Common laxatives include senna products, milk of magnesia, and propylene glycol solutions (eg, MiraLax, GlycoLax).

Perioperative medications

Routine pain medications for surgical procedures are warranted. Acetaminophen (15 mg/kg every 4 h) or morphine sulfate (0.05-0.1 mg/kg intravenously every 2-4 h) usually suffices.

The usual perioperative antibiotics include ampicillin (50 mg/kg every 6 h), gentamicin (2 mg/kg every 8-12 h), and clindamycin (10 mg/kg every 8 h).

Many laxatives have been used to control constipation in these patients. Senna comes in various forms and can be highly effective, although dosage must be individualized. The clinician must be personally engaged and must establish an effective dose response for each patient on a case-by-case basis.

Balanced electrolyte solutions have been used for years as a bowel preparation for surgical procedures. These solutions have only recently been made available in powdered form for mixing at home and for use as a laxative (under the name MiraLax or GlycoLax). These nonstimulant laxatives are very palatable to children because they dissolve in any beverage with minimal impact on taste.

In children who require urinary prophylaxis, standard medications include amoxicillin (first-line medication in newborns), nitrofurantoin, and trimethoprim/sulfamethoxazole (not used in babies aged < 2 mo). To ascertain a prophylaxis dose for one of these antibiotics, calculate a treatment dose based on the normal administration interval (2, 3, or 4 times per day) and then administer that same dose once per day. For example, if the amoxicillin treatment dose is 20-50 mg/kg/d divided every 8 hours and a patient weighs 10 kg, the normal dose may be 30 mg/kg/d (which falls within the recommended range). Because the patient weighs 10 kg, the dose is 100 mg every 8 hours. The prophylaxis dose would then be a once-daily dose of 100 mg.