Rimantadine (Flumadine) has activity against three subtypes of influenza viruses namely H1N1, H2N2, and H3N2. Because of increasing resistance, it is rarely used nowadays for the prophylaxis or treatment of influenza infection.

Rimantadine Uses:

• Prophylaxis of Influenza A virus:

  • It is indicated for the prophylaxis against influenza A virus in adults and children 1 year of age or older.

• Treatment of Influenza A virus:

  • It is indicated for the treatment of illness caused by influenza A virus in adults.

Note: Please refer to the current CDC guidelines regarding the current treatment and prophylaxis of influenza A virus. Rimantadine is no longer recommended for prophylaxis or treatment of influenza A virus because of the high rates of resistance to the drug.

Rimantadine Dose in Adults

Note:

• Please refer to the current CDC guidelines regarding the current treatment and prophylaxis of influenza A virus.
• Rimantadine is no longer recommended for prophylaxis or treatment of influenza A virus because of the high rates of resistance to the drug.

Rimantadine Dose in the prophylaxis of Influenza A virus:

• 100 mg orally two times a day for one week after the last known exposure.
• In institutional outbreaks, the treatment should be given for at least 2 weeks and up to seven days after the last exposure. The treatment after inactivated influenza vaccination should also be continued for two weeks until immunity develops.

Rimantadine Dose in the treatment of Influenza A virus:

• 100 mg orally two times a day for 5 to 7 days.

Note: The treatment should be initiated within 48 hours of symptom onset

Rimantadine Dose in Childrens

Rimantadine Dose in the prophylaxis of Influenza A virus in children:

Note:

• Please refer to the current CDC guidelines regarding the current treatment and prophylaxis of influenza A virus. Rimantadine is no longer recommended for prophylaxis or treatment of influenza A virus because of the high rates of resistance to the drug.
• Monotherapy is not recommended. It may be used in combination with oseltamivir if zanamivir can not be used and virus subtyping is not possible or not available plus oseltamivir-resistant viruses are circulating.
• The treatment should be continued for two weeks or more and for about ten days after the onset of illness in the last patient.

• Children 1 to 9 years:

  • 5 mg/kg/day orally in 1 to 2 divided doses.
  • The maximum daily dose is 150 mg/day.

• Children ≥10 years and Adolescents:

  • 5 mg/kg/day orally in 1 to 2 divided doses.
  • The maximum daily dose is 200 mg/day.

Rimantadine Dose in the treatment of Influenza A infection in Children:

Note: Note: Please refer to the current CDC guidelines regarding the current treatment and prophylaxis of influenza A virus. Rimantadine is no longer recommended for prophylaxis or treatment of influenza A virus because of the high rates of resistance to the drug. The optimal duration of treatment has not been established but may be given for 5 to 7 days. The treatment must be discontinued as soon as possible to reduce the emergence of antiviral drug resistance.

• Children 1 to 9 years:

  • 6.6 mg/kg/day orally in two divided doses.
  • The maximum daily dose is 150 mg/day.

• Children ≥10 years and Adolescents:

  • 5 mg/kg/day orally in 1 to 2 divided doses.
  • The maximum daily dose is 200 mg/day.

Pregnancy Risk Factor C

• Animal reproduction studies have shown adverse pregnancy outcomes. Untreated influenza infection can also increase the risk of adverse maternal and fetal outcomes.
• For the treatment or prophylaxis, neuraminidase inhibitors should be used in pregnant women as well as up to 2 weeks after birth.
• Pregnant women should not receive antiviral drugs as a substitute for vaccination. They should be used as an adjunct to vaccine.

Use during breastfeeding:

• It is unknown if the drug will be excreted into breastmilk.
• The manufacturer suggests that breastfeeding mothers avoid adverse reactions or stop breastfeeding because of the possibility of serious side effects.
• Postpartum women should get influenza checked immediately. This could lead to serious illnesses.

Dose in Kidney Disease:

• CrCl ≥30 mL/minute:
  • There are no dosage adjustments provided in the manufacturer's labeling;
  • Use it with caution.
• CrCl <30 mL/minute:
  • 100 mg once daily
• Hemodialysis:
  • Nondialyzable

Dose in Liver disease:

• Mild to moderate impairment:
  • There are no dosages adjustments provided in the manufacturer's labeling;
  • Use it with caution.
• Severe impairment:
  • 100 mg once daily.

Side Effects of Rimantadine (Flumadine):

• Central Nervous System:

  • Insomnia
  • Lack Of Concentration
  • Dizziness
  • Nervousness
  • Fatigue
  • Headache

• Gastrointestinal:

  • Nausea
  • Anorexia
  • Vomiting
  • Xerostomia
  • Abdominal Pain

• Neuromuscular & skeletal:

  • Weakness

Contraindications to Rimantadine (Flumadine):

Hypersensitivity to rimantadine, other adamantanes such as amantadine, or any component of the formulation.

Warnings and precautions

• Hepatic impairment

  • Patients suffering from liver disease should be cautious when taking the drug.

• Renal impairment

  • It should be used with caution by patients with impaired renal function.

• Seizures:

  • Seizures are more common when the drug is used. 
  • Patients who have had seizure disorders in the past should be warned about this drug. 
  • If seizures occur, the treatment should be stopped.

Rimantadine: Drug Interaction

Monitoring parameters:

Monitor for adverse gastrointestinal and central nervous system-related side effects especially in the elderly and those with liver or renal impairment.

How to administer Rimantadine?

It may be administered orally without regard to meals.

Mechanism of action of Rimantadine (Flumadine):

• It inhibits three types of influenza viruses, H1N1, H2N2, H3N2, and H3N2. 
• It may inhibit the uncoating process, which could inhibit viral replication.
• It has antiviral activity that is 2-8 times greater than amantadine, but has no activity against influenza B virus.

The beginning of action:

• Clinical trials have not shown that the plasma concentrations at which the drug begins to work antivirally are correlated with the drug's antiviral activity.

Absorption:

• It is well absorbed when administered orally.

Protein Binding:

• About 40% is bound to plasma proteins, primarily to albumin.

Metabolism:

• It is extensively metabolized in the liver via hydroxylation and glucuronidation.

Half-life elimination:

• Children 5 to 8 years: 24.8 ± 9.4 hours.
• Adults: 25.4 hours (range: 13 to 65 hours);
• Elderly (71 to 79 years of age): 32 hours (range: 20 to 65 hours)

Time to peak:

• 6 hours

Excretion:

• Urine (Less than 25% is excreted in urine as unchanged drug)

International Brand Names of Rimantadine:

• Flumadine
• Gabirol
• Jin Di Na
• Oclovir
• Remantadin
• Rimantaflu
• Roflual
• Rymanta
• Voctrexed

Rimantadine Brand Names in Pakistan:

No Brands Available in Pakistan.