Home Drug Guide Amantadine Hydrochloride

Drug Guide

Generic Name

Amantadine Hydrochloride

Brand Names Symmetrel, Symadine, Gocovri, Osmolex Er

Classification

Therapeutic: Antiviral and antiparkinsonian agent

Pharmacological: NPDA (N-methyl-D-aspartate) receptor antagonist, Dopamine releaser

FDA Approved Indications

  • Prevention and treatment of influenza A virus infections
  • Parkinson's disease (adjunct therapy)
  • Drug-induced extrapyramidal symptoms

Mechanism of Action

Amantadine inhibits viral replication by blocking the M2 protein of the influenza A virus, impairing uncoating of viral RNA. In Parkinson's disease, it increases dopamine release and blocks dopamine reuptake, providing antiparkinsonian effects.

Dosage and Administration

Adult: 200 mg per day in divided doses (e.g., 100 mg twice daily); adjust based on response and tolerance

Pediatric: Typically 3-12 years old: 7 mg/kg/day in divided doses (maximum 200 mg/day); use with caution

Geriatric: Start at lower doses (e.g., 100 mg once daily), increase gradually based on response and tolerability

Renal Impairment: Adjust dose according to renal function; e.g., for creatinine clearance <50 mL/min, dose reduction recommended

Hepatic Impairment: No specific adjustments; caution advised

Pharmacokinetics

Absorption: Well absorbed from gastrointestinal tract

Distribution: Widely distributed; crosses blood-brain barrier

Metabolism: Minimal hepatic metabolism

Excretion: Primarily renal excretion unchanged in urine

Half Life: 15-20 hours in healthy adults; longer in renal impairment

Contraindications

  • Hypersensitivity to amantadine
  • History of seizure disorder

Precautions

  • Use with caution in patients with renal impairment, history of psychiatric disorders, or cardiovascular disease. Monitor for confusion, hallucinations, and orthostatic hypotension. Caution during pregnancy and lactation; consult risk-benefit ratio.

Adverse Reactions - Common

  • Nausea (Most common)
  • Insomnia (Common)
  • Dizziness (Common)
  • Constipation (Common)

Adverse Reactions - Serious

  • Livedo reticularis (skin discoloration) (Rare)
  • Neuropsychiatric effects (hallucinations, agitation, confusion) (Rare)
  • Seizures (Rare)
  • Anaphylaxis (Rare)

Drug-Drug Interactions

  • Anticholinergics (may enhance anticholinergic side effects)
  • centrally acting agents (additive CNS effects)
  • Other drugs affecting renal function

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor renal function, neurological status, and mental health status regularly.

Diagnoses:

  • Risk for falls related to dizziness or orthostatic hypotension
  • Risk for confusion or altered mental status

Implementation: Administer with food to reduce gastrointestinal upset. Educate patients about potential neuropsychiatric side effects.

Evaluation: Assess therapeutic response (e.g., symptom control in Parkinson's), monitor for adverse effects, and adjust dose accordingly.

Patient/Family Teaching

  • Take medication exactly as prescribed.
  • Report any neuropsychiatric symptoms or skin discoloration.
  • Do not stop medication abruptly without consulting your healthcare provider.
  • Maintain adequate hydration and report any signs of urinary retention or hallucinations.

Special Considerations

Black Box Warnings:

  • Neuropsychiatric adverse reactions, including hallucinations, agitation, and depression, may occur, particularly in elderly patients or those with preexisting psychiatric conditions.

Genetic Factors: None specifically identified.

Lab Test Interference: May cause false positives in certain laboratory tests (e.g., urinary catecholamine tests).

Overdose Management

Signs/Symptoms: CNS stimulation (agitation, hallucinations), orthostatic hypotension, urinary retention, seizures in severe cases.

Treatment: Supportive care, activated charcoal if within 1 hour of ingestion, and symptomatic treatment. Hemodialysis may be considered in severe cases, especially with renal failure.

Storage and Handling

Storage: Store at room temperature, away from moisture and light.

Stability: Stable under recommended conditions; check manufacturer’s instructions for expiration date.

🛡️ 5 Critical Medication Safety Tips for Nurses

1

Triple-Check High-Risk Medications

Always have another nurse verify insulin, heparin, warfarin, and chemotherapy drugs. These "high-alert" medications cause the most serious errors. Check concentration, dose calculation, and pump settings twice.

2

Know Look-Alike, Sound-Alike Drugs

Common mix-ups: hydromorphone/morphine, Celebrex/Celexa, Zyprexa/Zyrtec. Always use BOTH generic and brand names, read labels twice, and use barcode scanning when available. One wrong letter can be fatal.

3

Assess Before AND After Giving Meds

Check vitals before cardiac meds, pain levels before analgesics, and blood glucose before insulin. Always reassess within 30 minutes to evaluate effectiveness and watch for adverse reactions.

4

Watch for Drug Interactions

Common dangerous combinations: warfarin + aspirin (bleeding), ACE inhibitors + potassium (hyperkalemia), digoxin + diuretics (toxicity). Always check drug interactions before administering new medications.

5

Educate Your Patients

Teach patients medication names, purposes, major side effects, and what to report. Informed patients catch errors and improve compliance. Always encourage questions - an educated patient is a safer patient.

⚡ Remember: When in doubt, don't give it out! It's always safer to double-check than regret later.

⚠️ Medical Disclaimer

This drug guide is for educational purposes only and is NOT intended for clinical use. Always consult current prescribing information, healthcare providers, and institutional protocols before administering any medication. Do not use this information for patient care decisions.