AMANTADINE

Antimicrobial activity

Amantadine inhibits the replication of influenza A virus isolates from each of the subtypes, i.e., H1N1, H2N2 and H3N2.

Pregnancy Risk Factor

Class C

Contraindication/Precaution

Hypersensitivity to amantadine,  or any component
Not recommended with nursing mothers
Use caution if heart failure or cardio-vascular disease
Use caution if seizure disorder
Use caution if renal/liver dysfunction
The safety and efficacy of amantadine in newborn infants and infants below the age of 1 year have not been established.

Mechanism of Action

Not clearly understood. Prevent the release of infectious viral nucleic acid into the host cell by interfering with the function of the transmembrane domain of the viral M2 protein. In certain cases, prevent virus assembly during virus replication.

Pharmacodynamics

Metabolism: N/A
Half-life: 10-28 hours, changes with renal function
Elimination: excreted in urine

Dosage

Children:

>1 to 9 years old: 
4.4-8.8 mg/kg/day (max: 150 mg/ day)
9-12 years old:
200 mg PO qd

Adults:

Influenza treatment/prophylaxis:
200 mg PO qd or 100 mg PO bid

Dose VS renal function

Cr. clearance (ml/min):
<10: give q7days 10-50: q48-72h >50-90:  q24-48h
>90: unchanged

Dialysis
Hemo: 200 mg q7days
CAPD: none