TABLE 15. Empiric* postexposure prophylaxis for preterm and full-term neonates 32–44 weeks’ postmenstrual age (gestational age plus chronologic age) after exposure to Bacillus anthracis, by descending order preference — CDC recommendations, 2023.

Treatment	32 to <34 weeks’ gestational age		34 to <37 weeks’ gestational age		Full-term infant
	0 to <1 week	1–4 weeks	0 to <1 week	1–4 weeks	0 to <1 week	1–4 weeks
	Dosage	Dosage	Dosage	Dosage	Dosage	Dosage
First-line antimicrobial drug
PCN-S only†:
Amoxicillin§,¶	25 mg/kg every 12 hours orally	25 mg/kg every 8 hours orally	25 mg/kg every 8 hours orally	25 mg/kg every 8 hours orally	25 mg/kg every 8 hours orally	25 mg/kg every 8 hours orally
Penicillin VK§	25 mg/kg every 12 hours orally	25 mg/kg every 8 hours orally	25 mg/kg every 12 hours orally	25 mg/kg every 8 hours orally	25 mg/kg every 8 hours orally	25 mg/kg every 6 hours orally
Penicillin G** aqueous	25,000 units/kg every 12 hours IM	25,000 units/kg every 12 hours IM	25,000 units/kg every 12 hours IM	25,000 units/kg every 12 hours IM	25,000 units/kg every 12 hours IM	25,000 units/kg every 12 hours IM
Amoxicillin/clavulanate§	25 mg amoxicillin/kg every 12 hours orally	25 mg amoxicillin/kg every 8 hours orally	25 mg amoxicillin/kg every 8 hours orally	25 mg amoxicillin/kg every 8 hours orally	25 mg amoxicillin/kg every 8 hours orally	25 mg amoxicillin/kg every 8 hours orally
Ciprofloxacin**	7.5 mg/kg every 12 hours orally	12.5 mg/kg every 12 hours orally	12.5 mg/kg every 12 hours orally	12.5 mg/kg every 12 hours orally	12.5 mg/kg every 12 hours orally	12.5 mg/kg every 12 hours orally
Clindamycin§	7 mg/kg every 8 hours orally	7 mg/kg every 8 hours orally	7 mg/kg every 8 hours orally	7 mg/kg every 8 hours orally	9 mg/kg every 8 hours orally	9 mg/kg every 8 hours orally
Doxycycline**,††, §§	5 mg/kg every 12 hours orally	5 mg/kg every 12 hours orally	5 mg/kg every 12 hours orally	5 mg/kg every 12 hours orally	5 mg/kg x 1dose orally, then 2.5 mg/kg every 12 hours orally	5 mg/kg x 1 dose orally, then 2.5 mg/kg every 12 hours orally
Levofloxacin**	10 mg/kg every 12 hours orally	10 mg/kg every 8 hours orally	10 mg/kg every 12 hours orally	10 mg/kg every 8 hours orally	10 mg/kg every 12 hours orally	10 mg/kg every 8 hours orally
Alternative antimicrobial drug ¶¶
Moxifloxacin††,***	10 mg/kg every 24 hours orally	10 mg/kg every 24 hours orally	10 mg/kg every 24 hours orally	10 mg/kg every 24 hours orally	10 mg/kg every 24 hours orally	10 mg/kg every 24 hours orally
Linezolid§,†††	10 mg/kg every 12 hours orally	10 mg/kg every 8 hours orally	10 mg/kg every 12 hours orally	10 mg/kg every 8 hours orally	10 mg/kg every 12 hours orally	10 mg/kg every 8 hours orally
Antitoxin (only to be used if antimicrobial drugs are not available or not appropriate; listed antitoxins joined by “or” are considered equivalent)
Raxibacumab§§§	55 mg/kg as a single dose IV	55 mg/kg as a single dose IV	55 mg/kg as a single dose IV	55 mg/kg as a single dose IV	55 mg/kg as a single dose IV	55 mg/kg as a single dose IV
or
Obiltoxaximab§§§	16 mg/kg as a single dose IV	16 mg/kg as a single dose IV	16 mg/kg as a single dose IV	16 mg/kg as a single dose IV	16 mg/kg as a single dose IV	16 mg/kg as a single dose IV

Abbreviations: FDA = Food and Drug Administration; IM = intramuscular; IV = intravenous; PCN-S = penicillin-susceptible strains; PEP = postexposure prophylaxis; PEPAbx = antimicrobial postexposure prophylaxis for anthrax.

* Definitive therapy should be directed by antibiotic susceptibility test results, when available.

^† Up to 10% of naturally occurring strains of anthrax are penicillin- and amoxicillin-resistant; bioterror strains might be engineered to generate resistance to multiple antibiotics. Susceptibility results reported from CDC within 48–72 hours of initial isolation of anthrax.

^§ Not approved by FDA for anthrax PEPAbx or treatment.

^¶ Ampicillin can be used as an alternative to amoxicillin, if available.

** Approved by FDA for anthrax PEPAbx, treatment, or both, but specific uses (e.g., doses, dosing schedules, and patient populations) recommended in this report might differ from the FDA-approved labeling.

^†† Instructions are available for preparing oral suspensions of moxifloxacin (Source: Hutchinson DJ, Johnson CE, Klein KC. Stability of extemporaneously prepared moxifloxacin oral suspensions. Am J Health Syst Pharm 2009;66:665–7.121) and doxycycline (Source: CDC. In an anthrax emergency: how to prepare doxycycline hyclate for children and adults who cannot swallow pills. Atlanta, GA: US Department of Health and Human Services, CDC; 2020. https://www.cdc.gov/anthrax/public-health/doxy-crushing-instruction-pamphlet.html).

^§§ The use of tetracycline-class antibiotics during tooth development (i.e., last half of pregnancy, infancy, and childhood up to age 8 years) might cause permanent discoloration of the teeth (yellow, gray, or brown) and enamel hypoplasia. This adverse effect appears to occur less often with doxycycline but might occur more with longer durations of therapy.

^¶¶ Alternative selections are for patients who have contraindications to or cannot tolerate first-line antimicrobial drugs or if first-line antimicrobial drugs are not available.

*** Not approved by FDA for any pediatric indications. Not approved by FDA for anthrax PEPAbx or treatment.

^††† Linezolid can be considered for PEP in scenarios when patients can receive regular monitoring for myelosuppression or neurotoxicity, which might occur within 14–28 days of use. If possible, switch to a different drug when available.

^§§§ Premedicate with IV or oral diphenhydramine within 1 hour before administration. Hypersensitivity and anaphylaxis have been reported after raxibacumab and obiltoxaximab administration.