Chemoprophylaxis to Influenza A With Amantadine or Ramantadine

 

Patients who may benefit from influenza chemoprophylaxis:

(1) unvaccinated persons who are (a) in contact with persons at high risk for influenza complications or (b) persons at high risk for complications who reside in an institutional setting

(2) unvaccinated persons who wish to avoid influenza A

(3) vaccinated persons exposed to influenza before immunity develops (immunity develops about 14 days after immunization)

(4) immune deficient persons who might not develop protective immunity following vaccination

(5) persons with a contraindication to vaccination, usually hypersensitivity to egg products or vaccine components

 

Patients who would not benefit from influenza chemoprophylaxis

(1) persons exposed to influenza B

(2) persons vaccinated against influenza after immunity develops

 

Dosages

Age	Dose of Amantadine	Dose of Rimantadine
< 1 year of age	use not adequately evaluated	use not adequately evaluated
1-9 years of age	5 mg/kg/day up to 150 mg, divided into 2 doses	5 mg/kg/day up to 150 mg, divided into 2 doses
10-13 years of age weighing < 40 kg	5 mg/kg/day up to 150 mg, divided into 2 doses	5 mg/kg/day up to 150 mg, divided into 2 doses
10-13 years of age weighing >= 40 kg	100 mg twice daily	100 mg twice daily
14-64 years of age	100 mg twice daily	100 mg twice daily
>= 65 years of age	<= 100 mg/day	100 to 200 mg/day

 

 

Special dosage situations:

(1) liver disease

(1a) If the patient has severe liver disease, then reduce dosage of rimantadine to 100 mg/day.

(1b) In patients with moderate liver disease, administer usual dosages but monitor patients closely, being ready to reduce dose to 100 mg/day if adverse effects develop.

(2) kidney disease

(2a) If the creatinine clearance is <= 10 mL/min, then reduce dosage of rimantadine to 100 mg/day. See spreadsheet on amantadine in renal disease (under dosing antibiotics in renal failure).

(2b) In patients with moderate kidney disease, administer usual dosages but monitor patients closely, being ready to reduce dose to 100 mg/day if adverse effects develop.

 

The incidence of CNS side effects is higher in persons taking amantadine than those taking rimantadine.