An 8 month pregnant female arrives to the ED complaining about dysuria. She is nontoxic appearing, afebrile. Exam significant for +suprapubic tenderness, -CVA tenderness. UA +leuks, +nitrates.
1) What antibiotic regimen should she be started on as an outpatient?
2) What if she had fever, +CVA tenderness, or systemic findings consistent with pyelonephritis?
1) 1st line: Amoxicillin; 2nd line: Cephalexin.
Amoxicillin is considered safe during all stages of pregnancy is the first line agent for UTI during pregnancy. Cephalexin is a first generation cephalosporin which has limited activity against gram negatives making it a suboptimal agent but is considered safe during pregnancy. However, depending on local bacterial resistance profiles cephalexin may be appropriate.
Macrobid can be used during early pregnancy but not in late third trimester. Macrobid may cause hemolytic anemia in infants <1 month and in near-term infants. Nitrofurantoin is ineffective in upper UTI since it is not well systemically absorbed and is excreted unchanged in the urine reaching concentrations effective in cystitis only.Bactrim may cause hyperbilirubinemia in at term infants or near-term infants, also it can cause congenital malformations during early pregnancy. Fluroquinolones may cause cartilage damage in fetuses and infants.
2) 1st line: Ampicillin/Gentamycin or third generation cephalosporin
Ampicillin with gentamycin provides dual gram negative coverage and should be used instead of amoxicillin alone during pyelonephritis in pregnancy. Third generation cephalosporins are preferred over first or second generation cephalosporins for the empiric treatment of acute pyelonephritis due to concerns of antibiotic resistance. Cefazolin and ceftriaxone had been found to have equivalent efficacy to intravenous ampicillin plus gentamicin in a randomized trial of 179 pregnant patients.
2) Ban KM, Easter JS: Selected Urologic Problems; in Marx JA, Hockberger RS, Walls RM, et al (eds): Rosen’s Emergency Medicine: Concepts and Clinical Practice, ed 8. St. Louis, Mosby, Inc., 2014, (Ch) 99: p 1326-1356.