science

Rimantadine

Rimantadine is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Rimantadine rather than just read about it. In short: Rimantadine (INN, sold under the trade name Flumadine) is an orally administered antiviral drug 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.

Key takeaways

Rimantadine belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Rimantadine to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Rimantadine from memory before moving on to harder problems.

Reference excerpt

Rimantadine (INN, sold under the trade name Flumadine) is an orally administered antiviral drug 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. Rimantadine can mitigate symptoms, including fever. Both rimantadine and the similar drug amantadine are derivates of adamantane. Rimantadine is found to be more effective than amantadine because when used the patient displays fewer symptoms. Rimantadine was approved by the Food and Drug Administration (FDA) in 1994. Rimantadine was approved for medical use in 1993. 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.

Medical uses

Influenza A Rimantadine inhibits influenza activity by binding to amino acids in the M2 transmembrane channel and blocking proton transport across the M2 channel. 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. The M2 channel is known to be responsible for viral replication in the influenza virus. 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. Rimantadine is bound inside the pore to amantadine specific amino acid binding sites with hydrogen binding and van der Waals interactions. The ammonium group (with neighboring water molecules) is positioned towards the C terminus with the amantadane group is positioned towards the N-terminus when bound inside the M2 pore.

Influenza resistance Resistance to rimantadine can occur as a result of amino acid substitutions at certain locations in the transmembrane region of M2. This prevents binding of the antiviral to the channel. The mutation S31N binding site with rimantadine is shown in the image to the left. It shows rimantadine binding into lumenal (top) or peripheral (bottom) binding sites with influenza M2 channel Serine 31 (gold) or Asparagine 31 (blue).

Rimantadine enantiomers interactions with M2 Rimantadine, when sold as flumadine, is present as a racemic mixture; the R and S states are both present in the drug. Solid state NMR studies have shown that the R enantiomer has a stronger binding affinity to the M2 channel pore than the S-enantiomer of rimantadine. Antiviral assay and electrophysiology studies show that there is no significant difference between the R and S enantiomers in binding affinity to amino acids in the M2 channel. Since the enantiomers have similar binding affinity, they also have similar ability to block the channel pore and work as an effective antiviral. Rimantadine enantiomers R and S are pictured interacting with the M2 pore below to the right. This image shows that there is not a significant modeled difference between the R and S enantiomers.

Parkinson's disease Rimantadine, like its antiviral cousin amantadine, possesses antiparkinsonian activity and can be used in the treatment of Parkinson's disease. However, in general, neither rimantadine nor amantadine is a preferred agent for this therapy and would be reserved for cases of the disease that are less responsive to front-line treatments.

Others Rimantadine is shown to be effective against other RNA-containing viruses. It can treat arboviruses like Saint Louis encephalitis and Sindbis. Other viruses that can be treated with Rimantadine include respiratory syncytial and parainfluenza viruses. Rimantadine has also been shown to treat chronic hepatitis C.

Side effects 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. Common side effects include:

Nausea Upset stomach Nervousness Tiredness Lightheadedness Trouble sleeping (insomnia) Difficulty concentrating Confusion Rimantadine shows fewer CNS symptoms than its sister drug amantadine.

Interactions Taking paracetamol (acetaminophen, Tylenol) or acetylsalicylic acid (aspirin) while taking rimantadine is known to reduce the body's uptake of rimantadine by approximately 12%. Cimetidine also affects the body's uptake of rimantadine. Taking anticholinergic drugs with amantadine may increase underlying seizure disorders and aggravate congestive heart failure.

Pharmacology

Pharmacodynamics The related drugs memantine and to a much lesser extent amantadine are known to act as NMDA receptor antagonists. The affinity of rimantadine for the NMDA receptor does not seem to have been reported. Analogues of rimantadine are known to act as NMDA receptor antagonists.

Chemistry

Synthesis

1-carboxyadamatanones are reduced with sodium borohydride to create racemic hydroxy acid. Excess methyllithium is then added to create methyl ketones which when reduced with lithium aluminum hydride gives the amine group. The synthesis pictured to the left is a synthesis of rimantadine as synthesized in Europe.

History Rimantadine was discovered in 1963 and patented in 1965 in the US by William W. Prichard in Du Pont & Co., Wilmington, Delaware (patent on new chemical compound U.S. patent 3,352,912, 1965 and on the first method of synthesis U.S. patent 3,592,934, 1967). Prichard's methods of synthesis of rimantadine from the corresponding ketone oxime were based on its reduction with lithium aluminum hydride.

See also Adapromine Bromantane Memantine Tromantadine

References

External links 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

Illustrations

Worked examples

Example 1 — a first encounter with Rimantadine

Start with the simplest possible case. Write down what Rimantadine claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Rimantadine before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Rimantadine ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Rimantadine

In research: Rimantadine appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Rimantadine in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Rimantadine is common in secondary-school and first-year university syllabi. It links to neighbouring topics Adamantanes, Amines, Anti-influenza agents, so understanding it makes those chapters shorter.
In everyday life: Look for Rimantadine outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Rimantadine in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Rimantadine means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Rimantadine out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Rimantadine in simple terms?

Why does Rimantadine matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Rimantadine?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Rimantadine.