Use of Anti-Infective Agents During Lactation: Part 2—Aminoglycosides, Macrolides, Quinolones, Sulfonamides, Trimethoprim, Tetracyclines, Chloramphenicol, Clindamycin, and Metronidazole

Abstract

Because many antibiotics are excreted into breast milk, it can be difficult for a practitioner to choose an antibiotic for a lactating patient that will have minimal risks to her nursing infant. This article is the second of a three-part series discussing the use of anti-infective agents during lactation. The authors review general information regarding use and common side effects for several classes of antibiotics. They also summarize information, including documented milk concentrations, milk-to-plasma ratios, and other pharmacokinetic properties, in a table that can help practitioners choose antibiotics that may be considered safe to use in the lactating mother.

Antibiotics and Breastfeeding

“…Because breastmilk has a pH of 7.2, which is slightly lower than the pH of plasma (normal pH range 7.35-7.45), antibiotics with a higher pKa have a greater tendency to accumulate as an ionized form in breast milk [20,21]. …”

“…Unfortunately, this class of drugs is highly associated with the induction and spread of antimicrobial resistance, which has become a major concern as their use has become significantly more frequent in recent years [60][61]. Fluoroquinolones have good oral bioavailability, low protein binding and good tissue penetration, increasing the possibility of the passage of these drugs into breast milk (where they have been detected) [20]. Interestingly, these drugs have great reductions in oral bioavailability when administered with cations (e.g.…”

“…A great concern associated with the use of sulfonamide derivatives in children is the appearance of kernicterus due to the high affinity of these drugs for serum albumin; as a result, these drugs displace bilirubin, increasing the concentration of this molecule in the serum of newborns [20]. Also, there is a risk of hemolytic anemia in infants who have G-6-PD (glucose-6-phosphate-dehydrogenase) deficiency [20]. Despite the potential for the emergence of kernicterus and hemolytic anemia, the risk appears to be small [91].…”

“…Another important factor in the excretion of cotrimoxazole in breast milk is the high degree of plasma protein binding of this drug (table 1). Because only the free fraction can be distributed, the amount that reaches the milk is lower [20]. In 2000, the World Health Organization proposed that all African newborns born to mothers with HIV should receive cotrimoxazole from 6 weeks of age until the end of breastfeeding, as a prophylactic agent to protect against Pneumocystis jirovecii pneumonia.…”

“…Chloramphenicol is an antibiotic with a broad spectrum of activity that acts against Gram-positive and Gram-negative bacteria, rickettsia, chlamydia, mycoplasma and spirochetes [20]. Chloramphenicol inhibits bacterial protein synthesis and exhibits bacteriostatic activity.…”