Clinical Care of Naegleria fowleri Infection

Key points

  • Primary amebic meningoencephalitis (PAM) caused by Naegleria fowleri is treated with a combination of medications.
  • There have been five well-documented survivors of PAM in North America.
Healthcare provider wearing gloves hooks up an IV

Medication options

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Clinicians: For 24/7 diagnostic assistance, specimen collection guidance, shipping instructions, and treatment recommendations, please contact the CDC Emergency Operations Center at 770-488-7100.

A combination of medications is recommended for treatment of Naegleria fowleri infections. These drugs have been used in PAM survivors. Many have been found to have antiamebic activity against Naegleria fowleri in the laboratory.

Drug Dose Route Maximum Dose Duration Comments
Amphotericin B* 1.5 mg/kg/day in 2 divided doses, THEN IV 1.5 mg/kg/day 3 days
1 mg/kg/day once daily IV 11 days 14-day course
Amphotericin B 1.5 mg once daily, THEN Intrathecal 1.5 mg/day 2 days
1 mg/day every other day Intrathecal 8 days 10-day course
Azithromycin 10 mg/kg/day once daily IV/PO 500 mg/day 28 days
Fluconazole 10 mg/kg/day once daily IV/PO 600 mg/day 28 days
Rifampin 10 mg/kg/day once daily IV/PO 600 mg/day 28 days
Miltefosine** Weight<45 kg 50 mg BID
Weight>45kg 50 mg TID		 PO 2.5 mg/kg/day 28 days 50 mg tablets
Dexamethasone 0.6 mg/kg/day in 4 divided doses IV 0.6 mg/kg/day 4 days

*Conventional amphotericin (AMB) is preferred. When AMB was compared with liposomal AMB against Naegleria fowleri, the minimum inhibitory concentration (MIC) for AMB was 0.1 µg/mL, while that of liposomal AMB was 10x higher at 1 µg/ml. Liposomal AMB was found to be less effective in the mouse model and in in vitro testing than the more toxic form of AMB. AMB methyl ester was also found to be less effective in the mouse model. Because the prognosis of Naegleria fowleri infection is extremely poor, consider aggressive treatment.

**The table lists the standard miltefosine dose in adults. A higher dose leads to increased nausea, vomiting, or diarrhea. Miltefosine is mildly nephrotoxic and the dosing may need to be adjusted for patients with impaired kidney function. However, few data are available about the effective dose for amebic infection. The risk of nephrotoxicity should be balanced with the risk for death from PAM. Miltefosine is now commercially available. Please visit impavido.com for more information.

Survivor medications

Although most people who get PAM caused by a Naegleria fowleri infection don't survive, there have been five documented cases of survivors in North America.

U.S. Survivor
(1978)		 Mexico Survivor
(2003)		 U.S. Female Survivor
(2013)		 U.S. Male Survivor
(2013)		 U.S. Survivor
(2016)
Amphotericin B
(IV and intrathecal)		 Amphotericin B
(IV)		 Amphotericin B
(IV and intrathecal)		 Amphotericin B
(IV and intrathecal)		 Amphotericin B
(IV and intrathecal)
Rifampin
(oral)		 Rifampin
(oral)		 Rifampin
(IV/oral)		 Rifampin
(oral)		 Rifampin
(IV/oral)
Miconazole
(IV and intrathecal) No longer available in the U.S.		 Fluconazole
(IV and oral)		 Fluconazole
(IV/oral)		 Fluconazole
(IV)		 Fluconazole
(IV/oral)
Sulfisoxazole
(IV)
Discontinued after Naegleria fowleri infection diagnosed		 Ceftriaxone
(IV)		 Azithromycin (IV/oral) Azithromycin
(IV/oral)		 Azithromycin (IV/oral)
Phenytoin Miltefosine
(oral)		 Miltefosine
(oral)		 Miltefosine
(oral)
Dexamethasone Dexamethasone (IV) Dexamethasone (IV) Dexamethasone (IV) Dexamethasone (IV)
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Content Source:
National Center for Emerging and Zoonotic Infectious Diseases (NCEZID)