Nitrofurantoin

General

• Type: Antibiotic
• Dosage Forms: oral
• Common Trade Names: Macrobid

Adult Dosing

• Monohydrate/macrocrystals (Macrobid): 100mg PO q12h
• Macrocrystals: 50-100mg PO 4 times daily

Pediatric Dosing

• >12yo: same as adult dosing

Special Populations

• Pregnancy Rating: B
• Lactation Risk: Infant risk minimal
• Renal Dosing: Contraindicated if CrCl <60
• Hepatic dosing:

Contraindications

• Allergy to class/drug
• Neonates, pregnant women at term or when delivery imminent
• Renal failure due to accumulation of metabolites that may cause peripheral neuropathy
• Cholestatic jaundice history
• CrCL < 60
• Oliguria
• Anuria

Adverse Reactions

Serious

• Hemolytic anemia can occur in patients with G6PD deficiency and in infants less than 1 month old
• Hepatic necrosis
• Hepatitis
• Cholestatic jaundice syndrome
• Erythema multiforme/SJS
• Pancreatitis
• Peripheral neuropathy
• Pulmonary hypersensitivity
• Agranulocytosis
• Leukopenia
• Thrombocytopenia
• Pneumonitis
• Pulmonary fibrosis
• Cyanosis
• ECG abnormality
• C. difficle associated diarrhea
• Optic neuritis
• Pseudotumor cerebri
• Psychosis
• Vasculitis

Common

• Nausea
• Headache
• Anorexia
• Abdominal pain
• Diarrhea
• Flatulence
• Asthenia
• Vertigo
• Nystagmus
• Dizziness
• Confusion
• Depression
• Alopecia
• Yellow/brown urine
• Sialadenitis
• Fever
• Prutitus
• Urticaria
• Arthralgia
• Myalgia
• Rigors

Pharmacology

• Half-life: 45-60min
• Metabolism: Hepatic
• Excretion: Urine primarily (30-40% unchanged); Bile
• Mechanism of Action: Inactivates bacterial ribosomal proteins

Antibiotic Sensitivities

Group	Organism	Sensitivity
Gram Positive	Strep. Group A, B, C, G	S
	Strep. Pneumoniae	S
	Viridans strep	X1
	Strep. anginosus gp	X1
	Enterococcus faecalis	S
	Enterococcus faecium	S
	MSSA	S
	MRSA	S
	CA-MRSA	S
	Staph. Epidermidis	X1
	C. jeikeium	R
	L. monocytogenes	X1
Gram Negatives	N. gonorrhoeae	S
	N. meningitidis	X1
	Moraxella catarrhalis	X1
	H. influenzae	X1
	E. coli	S
	Klebsiella sp	I
	E. coli/Klebsiella ESBL+	X1
	E coli/Klebsiella KPC+	R
	Enterobacter sp, AmpC neg	I
	Enterobacter sp, AmpC pos	I
	Serratia sp	X1
	Serratia marcescens	R
	Salmonella sp	S
	Shigella sp	S
	Proteus mirabilis	X1
	Proteus vulgaris	R
	Providencia sp.	X1
	Morganella sp.	X1
	Citrobacter freundii	X1
	Citrobacter diversus	X1
	Citrobacter sp.	X1
	Aeromonas sp	X1
	Acinetobacter sp.	X1
	Pseudomonas aeruginosa	R
	Burkholderia cepacia	R
	Stenotrophomonas maltophilia	R
	Yersinia enterocolitica	X1
	Francisella tularensis	X1
	Brucella sp.	X1
	Legionella sp.	X1
	Pasteurella multocida	X1
	Haemophilus ducreyi	X1
	Vibrio vulnificus	X1
Misc	Chlamydophila sp	R
	Mycoplasm pneumoniae	X1
	Rickettsia sp	X1
	Mycobacterium avium	X1
Anaerobes	Actinomyces	X1
	Bacteroides fragilis	X1
	Prevotella melaninogenica	X1
	Clostridium difficile	X1
	Clostridium (not difficile)	X1
	Fusobacterium necrophorum	X1
	Peptostreptococcus sp.	X1

Key

• S susceptible/sensitive (usually)
• I intermediate (variably susceptible/resistant)
• R resistant (or not effective clinically)
• S+ synergistic with cell wall antibiotics
• U sensitive for UTI only (non systemic infection)
• X1 no data
• X2 active in vitro, but not used clinically
• X3 active in vitro, but not clinically effective for Group A strep pharyngitis or infections due to E. faecalis
• X4 active in vitro, but not clinically effective for strep pneumonia