II. Indications
- Precaution: Do not use for Influenza management as of 2011 CDC Guidelines
- Due to resistance, these agents are not now routinely used for Influenza treatment and prophylaxis (use Neuraminidase Inhibitors)
- CDC no longer recommends Amantadine or Rimantadine for Influenza management
- Use Neuraminidase Inhibitors instead
- Prior indications for Influenza A management (no longer used)
- Influenza Prophylaxis
- Given if Vaccine contraindicated
- Can be given concurrently with Influenza Vaccine
- Covers 2 week period until Immunity established
- Influenza A Treatment
- Shortens course by 1 day and lessens symptoms
- Start within 48 hours to be effective
- Influenza Prophylaxis
-
Influenza B is not covered by these antiviral agents
- See Neraminidase Inhibitors: Oseltamivir (Tamiflu) or Zanamivir (Relenza)
III. Contraindications
- Absolute Contraindications
- Relative Contraindications for Amantadine
- Age over 65 years
- Renal Insufficiency
IV. Supplied
- Tablets: 100 mg
- Syrup: 50 mg/5cc
V. Dosing
- General
- Age 1-9 years old or weight under 40 kg
- Amantadine 5mg/kg/day divided bid (up to 75 mg bid)
- Rimantadine 5mg/kg/day divided bid (up to 75 mg bid)
- Age 10 to 64 years old
- Amantadine 100 mg PO bid
- Rimantadine 100 mg PO bid
- Age over 65 years old
- Rimantadine 100 mg PO qd
- Amantadine 100 mg PO qd (avoid if possible)
- Renal Insufficiency (based on Creatinine Clearance)
VI. Adverse Effects: CNS Side effects
- Consider split dosing especially in elderly
- Rimantadine causes less adverse effects than Amantadine
- Amantadine and Rimantadine cross blood-brain barrier
- Antihistamines may block drugs crossing barrier
- Spector (1988) J Pharmacol Exp Ther 244:516-9 [PubMed]
- Related Symptoms
- Jitteriness
- Anxiety
- Insomnia
- Lightheadedness
- Irritability
- Difficulty concentrating (5-10%)
VII. Adverse Effects: Gastrointestinal
VIII. Precautions
- Adjust dosing in Renal Insufficiency
IX. Resources
- CDC MMWR - ACIP Guidelines on antivirals in Influenza (2011)
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Related Studies
amantadine (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
AMANTADINE 100 MG CAPSULE | Generic | $0.24 each |
AMANTADINE 100 MG TABLET | Generic | $0.64 each |
AMANTADINE 50 MG/5 ML SOLUTION | Generic | $0.02 per ml |