Rimantadine (Flumadine®)


Rimantadine is a semisynthetic petroleum hydrocarbon derivative.

Antiviral Activity:

Rimantadine has activity against influenza A with little or no activity against influenza B.

Mechanism of Action:

The mechanism of action may involve inhibitors of the uncoating of the virus.

Mechanism of Resistance:

Resistance occurs due to point mutations in the M gene of viruses which leads to single amino acid substitutions in the transmembrane domain of the M2 protein. This allows the virus to uncoat in the presence of rimantadine. Resistant variants show cross-resistance to amantadine, rimantadine, and related compounds. Consequently, higher drug doses or alternative drugs with the same antiviral target are unable to overcome this problem.


Rimantadine oral absorption ranges from 75 to 93% and plasma protein binding is approximately 40%. It undergoes extensive metabolism by hydroxylation, conjugation and glucuronidation prior to renal elimination by glomerular filtration.

Adverse Effects:

Relatively common adverse events include nervousness, lightheadedness, difficulty concentrating, insomnia, fatigue, slurred speech, loss of appetite, and nausea. More serious CNS adverse effects include hyperexcitability, confusion, depression, tremors, mood disturbance, ataxia and gait disturbance, hallucinations, psychosis, and coma. Rimantadine has a lower risk of CNS reactions than amantadine.


100 mg tablets (100 tablet bottle)

Syrup 50mg/5ml (240ml bottle)


            18-64 years old – 100mg twice daily

            Frail elderly – 100mg daily


            < 10 years old – 5mg/kg once daily (max. 150mg)

            10-17 years old – 100mg twice daily

Disease state based dosing:

Renal Impairment (CrCl < 10 mL/min) – 100mg daily

Hepatic Dysfunction – 100mg daily       

Contraindications/Warnings/ Precautions:

Influenza A virus strains resistant to rimantadine can emerge during treatment and such resistant strains have been shown to be transmissible and to cause typical influenza illness.

Drug Interactions:

Antihistamines, antidepressants, and anticholinergic drugs increase the risk of CNS side effects when combined with rimantadine.


Category C: Risk unknown. Human studies inadequate.

Monitoring Requirements:

Renal function, liver function, neurologic exam

Brand names/Manufacturer:

Flumadine®/Forest Pharmaceuticals Inc.

Rimantadine/Global Pharmaceuticals Div of Impax Labs.,Inc., Inwood Laboratories Inc Sub Forest Laboratories Inc., Sandoz Pharmaceuticals