Rimantadine

Systematic (IUPAC) name
(RS)-1-(1-adamantyl)ethanamine
Clinical data
Trade names	Flumadine
AHFS/Drugs.com	monograph
MedlinePlus	a698029
Pregnancy cat.	C (United States)
Legal status	℞-only (U.S.)
Routes	Oral
Pharmacokinetic data
Bioavailability	well absorbed
Protein binding	40%
Metabolism	Hepatic hydroxylation and glucuronidation
Half-life	25.4 ± 6.3 hours
Excretion	Renal
Identifiers
CAS number	13392-28-4
ATC code	J05AC02
PubChem	CID 5071
DrugBank	DB00478
ChemSpider	4893 Y
UNII	0T2EF4JQTU Y
KEGG	D08483 Y
ChEMBL	CHEMBL959 Y
Chemical data
Formula	C12H21N
Mol. mass	179.302 g/mol
SMILES	eMolecules & PubChem
InChI InChI=1S/C12H21N/c1-8(13)12-5-9-2-10(6-12)4-11(3-9)7-12/h8-11H,2-7,13H2,1H3 Y Key:UBCHPRBFMUDMNC-UHFFFAOYSA-N Y
Y (what is this?)  (verify)

Rimantadine (INN, sold under the trade name Flumadine) is an orally administered antiviral drug^[1] used to treat, and in rare cases prevent, influenzavirus A infection. When taken within one to two days of developing symptoms, rimantadine can shorten the duration and moderate the severity of influenza. Both rimantadine and the similar drug amantadine are derivates of adamantane. Rimantadine was approved by the Food and Drug Administration (FDA) in 1994.

According to the CDC, 100% of seasonal H3N2 and 2009 pandemic flu samples tested have shown resistance to rimantadine and it is no longer recommended to prescribe for treatment of the flu.^[2]

History[link]

Rimantadine was discovered in 1963^[3][4][5] and patented in 1965 in the USA by William W. Prichard in Du Pont & Co., Wilmington, Delaware (US patent on new chemical compound № 3352912, 1965 and on the first method of synthesis № 3592934, 1967).^[5][6][7] Prichard's methods of synthesis of rimantadine from the corresponding ketone oxime were based on its reduction with lithium aluminum hydride.

Clinical usage[link]

Rimantadine is believed to inhibit influenza's viral replication, possibly by preventing the uncoating of the virus's protective shells, which are the envelope and capsid. Genetic studies suggest that the virus M2 protein, an ion channel specified by virion M2 gene, plays an important role in the susceptibility of influenza A virus to inhibition by rimantadine. Resistance to rimantadine can occur as a result of an amino acid substitutions at certain locations in the transmembrane region of M2. This prevents binding of the antiviral to the channel.^[8]

Rimantadine, like its antiviral cousin amantadine, possesses some NMDA antagonistic properties and is used as an antiparkinsonic drug (i.e., in the treatment of Parkinson's disease). However, neither rimantadine nor amantadine are preferred agents for this therapy and are generally reserved for cases of the disease which are less responsive to front-line treatments.

Drug interactions[link]

Taking paracetamol (acetaminophen e.g. Tylenol) or acetylsalicylic acid (aspirin) while taking rimantadine is known to reduce the body's uptake of rimantadine by approximately 12%.^[9] Cimetidine also affects the body's uptake of rimantadine.

Possible side effects[link]

Rimantadine can produce gastrointestinal and central nervous system adverse effects. Approximately 6% of patients (compared to 4% of patients taking a placebo) reported side effects at a dosage of 200 mg/d.^[10] Common side effects include:

• nausea
• upset stomach
• nervousness
• tiredness
• lightheadedness
• trouble sleeping
• difficulty concentrating

References[link]

External links[link]

• U.S. FDA press release announcing rimantadine's approval
• U.S. Center for Drug Evaluation and Research rimantadine description
• U.S. NIH rimantadine description
• U.S. CDC flu anti-viral treatment information
• Rimantadine bound to proteins in the PDB