Amantril 100 mg

Description

Indications

Amantril is prescribed for the following conditions:

• Management of Parkinson’s disease
• Treatment of drug-induced extrapyramidal reactions
• Prevention and treatment of infections caused by various strains of the influenza A virus

Take this medication as per the advice of a registered physician.

Pharmacology Amantadine Hydrochloride exerts both direct and indirect effects on dopamine neurons. It enhances dopamine release and inhibits its reuptake at the pre-synaptic level. Post-synaptically, it acts directly on dopamine receptors, leading to upregulation of D2 receptors, potentially due to receptor hypersensitivity. Additionally, Amantadine possesses antimuscarinic properties and exerts antiglutamatergic effects by non-competitively antagonizing NMDA receptors. This mechanism plays a role in reducing levodopa-induced dyskinesias. NMDA receptor sensitization is believed to be a key factor in the development of such dyskinesias.

Amantadine also exhibits immunomodulatory properties by restoring interleukin-2 (IL-2) production, which is often deficient in Parkinson’s disease patients. While the exact mechanism of its antiviral action remains unclear, it primarily inhibits the release of infectious viral nucleic acid into host cells by interfering with the function of the transmembrane domain of the viral M2 protein. Additionally, it prevents virus assembly during replication. Importantly, Amantadine does not compromise the immunogenicity of inactivated influenza A virus vaccines.

Dosage & Administration

Parkinson’s Disease:

• Adults: The typical starting dose is 100 mg twice daily when used as monotherapy.
• In patients with severe medical conditions or those receiving high doses of other antiparkinsonian medications, an initial dose of 100 mg once daily is recommended. This can be increased to 100 mg twice daily if needed after a few weeks.
• Some patients who do not achieve optimal response at 200 mg daily may benefit from doses up to 400 mg daily, administered in divided doses.
• Concomitant Therapy: Patients who do not respond to anticholinergic antiparkinson drugs may benefit from Amantadine. When used in combination with levodopa, it may enhance therapeutic benefits and help stabilize fluctuations in symptom relief. If levodopa side effects necessitate dose reduction, adding Amantadine may help compensate for lost efficacy.

Drug-Induced Extrapyramidal Reactions:

• Adults: Typically, 100 mg twice daily.
• In cases where 200 mg daily does not provide sufficient benefit, the dose may be increased up to 300 mg daily in divided doses.

Influenza A Virus Prophylaxis and Treatment:

• Adults: 200 mg/day, either as a single dose or in two divided doses of 100 mg each. If central nervous system (CNS) side effects occur, splitting the dose may alleviate symptoms.
• Elderly (over 65 years): 100 mg once daily.
• Children:
  • Ages 1 to 9 years: 4.4 to 8.8 mg/kg/day, not exceeding 150 mg per day.
  • Ages 9 to 12 years: 100 mg twice daily.

Administration Method: Capsules should be taken orally, with or without food.

Patients with Renal Impairment: Dosage adjustments are necessary, either by reducing the daily dose or increasing the dosing interval based on creatinine clearance levels.

Patients with Hepatic Impairment: Use with caution.

Take this medication as per the advice of a registered physician.

Drug Interactions

• Co-administration with anticholinergic agents or levodopa may increase the risk of confusion, hallucinations, nightmares, or other atropine-like side effects.
• Psychotic reactions have been observed in patients taking Amantadine and levodopa together.
• Combined use with CNS-active substances, including alcohol, may lead to additive CNS toxicity. Close monitoring is recommended.

Contraindications

• Hypersensitivity to Amantadine or any of its components.

Side Effects Most adverse effects are mild and may diminish over time. Common side effects include:

• Nausea
• Dizziness or lightheadedness
• Insomnia Other possible side effects:
• Swelling of ankles
• Livedo reticularis
• Anxiety, mood elevation, headache, lethargy, hallucinations, ataxia, slurred speech, blurred vision, nervousness, and depression
• Myalgia, palpitations, orthostatic hypotension
• Dry mouth, anorexia, constipation, and excessive sweating

Pregnancy & Lactation

• Pregnancy (Category C): There are no well-controlled studies on Amantadine use in pregnant women. It should only be used if the potential benefits outweigh the potential risks to the fetus.
• Lactation: Amantadine is excreted in breast milk in low concentrations. Its effects on infants are unknown; therefore, caution is advised when prescribing to breastfeeding women.

Precautions & Warnings

• Sudden discontinuation in Parkinson’s disease patients may lead to severe deterioration (parkinsonian crisis). The dose should be tapered gradually.
• If atropine-like effects occur when used with anticholinergic drugs, dosage adjustments may be necessary.
• Abrupt discontinuation can trigger symptoms such as delirium, hallucinations, paranoia, agitation, depression, slurred speech, and stupor.

Overdose Effects Amantadine overdose can be fatal. The lowest reported lethal dose is 1 gram. Some cases of overdose have been linked to suicide attempts.

Toxicity Symptoms:

• Cardiac issues: Arrhythmias, tachycardia, hypertension
• Respiratory complications: Pulmonary edema, respiratory distress
• Renal dysfunction: Elevated BUN, reduced creatinine clearance, renal insufficiency
• CNS effects: Insomnia, anxiety, agitation, hypertonia, tremors, confusion, hallucinations, psychosis, seizures, lethargy, coma, hyperthermia

Management of Overdose:

• No specific antidote exists. Intravenous physostigmine (1–2 mg in adults, 0.5 mg in children) at regular intervals has been reported to counter CNS toxicity.
• Supportive treatment includes gastric lavage, forced diuresis, and pH modulation to enhance drug excretion.
• Continuous monitoring of vital signs, including ECG, is essential.
• Sedation and anticonvulsant therapy may be required in cases of severe agitation or seizures.

Therapeutic Class Respiratory viral infections (Influenza)

Storage Conditions

• Keep out of reach of children.
• Store in a cool, dry place, protected from light.