Amantadine Hydrochloride

Amantadine hydrochloride is an antiviral drug used to treat Influenza A and Parkinson’s disease. It is an antiviral drug used to prevent or treat influenza A virus infections. It is also used to treat the symptoms of Parkinson’s disease, such as shakiness, difficulty speaking, and stiffness of muscles. Amantadine hydrochloride is also used to treat or prevent extreme drowsiness caused by certain drugs used to treat mental illnesses.

Uses For

Amantadine hydrochloride is used to treat or prevent viral infections caused by the Influenza A virus. It is also used to reduce extreme drowsiness caused by certain drugs used to treat mental illnesses. Amantadine hydrochloride is also used to reduce the symptoms of Parkinson's disease, such as difficulty speaking, shaking, and stiffness of muscles.

Mechanism Of Action

Amantadine hydrochloride inhibits the replication of the influenza A virus. The drug works by enhancing neuromuscular transmission, reducing synaptic transmission, and regulating calcium channels and dopamine transport. It also acts as an antagonist for voltage-gated calcium channels.

How Long Does It Take To Work

Amantadine hydrochloride works very quickly. When taken to treat influenza A, it begins to work within 24 hours after taking it. It can help reduce the severity and duration of the virus. When taken to treat the symptoms of Parkinson's disease, it can take several weeks to months to see improvement in symptoms.

Absorption

Amantadine hydrochloride is rapidly absorbed after oral administration. Peak plasma concentrations occur within one to two hours. The drug is well-distributed throughout the body, with concentrations in the brain and spinal fluid being five- to seven-times that of the plasma concentrations.

Route of Elimination

Amantadine hydrochloride is rapidly eliminated from the body, with 80% of the dose being excreted within 24 hours. Most of the drug is eliminated via the kidney, through active reabsorption and tubular secretion. It is also metabolized in the liver by the cytochrome P450 enzyme system.

Dosage

Parkinson's disease-

Adults: The usual dose is 100 mg twice a day when used alone.
The initial dose of Amantadine is 100 mg daily for patients with serious associated medical illnesses or who are receiving high doses of other antiparkinson drugs. After one to several weeks at 100 mg once daily, the dose may be increased to 100 mg twice daily, if necessary.
Occasionally, patients whose responses are not optimal with Amantadine at 200 mg daily may benefit from an increase up to 400 mg daily in divided doses.
Dosage for Concomitant Therapy: Some patients who do not respond to anticholinergic antiparkinson drugs may respond to Amantadine.
When Amantadine or anticholinergic antiparkinson drugs are each used with marginal benefit, concomitant use may produce additional benefit. When Amantadine and levodopa therapy are initiated concurrently, the patient can exhibit rapid therapeutic benefits. Amantadine dose, should be held constant at 100 mg daily or twice daily while the daily dose of levodopa is gradually increased to optimal benefit.
When Amantadine is added to optimal well-tolerated doses of levodopa, additional benefit may result, including smoothing out the fluctuations in improvement which sometimes occur in patients on levodopa alone. Patients who require a reduction in their usual dose of levodopa because of development of side effects may possibly regain lost benefit with the addition of Amantadine.

Drug-induced extrapyramidal reactions-

Adults: The usual dose is 100 mg twice a day.
Occasionally, patients whose responses are not optimal with Amantadine at 200 mg daily may benefit from an increase up to 300 mg daily in divided doses.

Prophylaxis and treatment of Influenza A virus illness-

Adults: 200 mg/day as single dose or 100 mg twice daily. If CNS effects develop on a once- daily dosage, split dosage schedule may reduce complaints.
Elderly over 65 years of age: 100 mg every day.
Children: 1 to 9 years of age: 4.4 to 8.8 mg/kg/day; not to exceed 150 mg/day. 9 to 12 years of age: 100 mg twice daily

Method of administration: Each capsule is to be taken orally either with or without food.

Patients with renal impairment: The dose should be reduced. This can be achieved by either reducing the total daily dose, or by increasing the dosage interval in accordance with the creatinine clearance.

Patients with hepatic impairment: Use with caution.

The recommended dose of Amantadine hydrochloride for treating influenza A virus infections is 100 mg taken twice daily. The recommended dose for treating Parkinson’s disease is 100 mg once daily or 50 mg twice daily. The dosage may be increased up to 200 mg once daily or 100 mg twice daily.

Administration

Amantadine hydrochloride is administered orally with food. Capsules and oral concentrate are available for oral administration. It should be taken as prescribed by the doctor. Avoid taking more or less than the prescribed dose.

Side Effects

Common side effects from Amantadine hydrochloride include nausea, vomiting, constipation, dry mouth, headache, blurred vision, and dizziness. More serious side effects include confusion, agitation, difficulty in breathing, and hallucinations. Other serious side effects include depression, shortness of breath, irregular heartbeat, and hallucinations.

Toxicity

The most common symptom of Amantadine hydrochloride toxicity is nausea and vomiting. Other symptoms may include dizziness, headache, confusion, agitation, and seizures. If the symptoms persist, it is recommended to call a healthcare provider.

Precautions

Patients taking Amantadine hydrochloride should be monitored for side effects such as confusion, agitation, and difficulty breathing. Patients with kidney, liver, or heart disease should use caution when taking the drug. It should be used with caution in pregnant or breastfeeding women.

Interaction

Amantadine hydrochloride can interact with other drugs, such as anticholinergics, antihistamines, antiseizure drugs, and diuretics. It can also interact with certain antibiotics, antipsychotics, and anticonvulsants. Patients should inform their doctor of all medications they are taking before taking Amantadine hydrochloride.

Disease Interaction

Amantadine hydrochloride may interact with certain conditions, including kidney disease, liver disease, seizure disorders, and heart disease. It should also be used with caution in patients with a history of depression or psychosis.

Drug Interaction

Amantadine hydrochloride may increase the levels of other drugs in the body, such as anticholinergics, antihistamines, antiseizure drugs, diuretics, antibiotics, antipsychotics, and anticonvulsants. It is important to tell your doctor about all medications you are taking before taking Amantadine hydrochloride.

Food Interactions

Amantadine hydrochloride may interact with certain foods, such as alcohol, caffeine, and grapefruit. It is important to tell your doctor about all foods you are taking before taking Amantadine hydrochloride.

Pregnancy and Lactation Use

Amantadine hydrochloride has been classified as category C by the U.S. Food and Drug Administration (FDA), meaning that there is no guarantee of safety for its use during pregnancy. It should only be used if the potential benefit justifies the potential risk to the fetus. As for lactation, there is no evidence of a transfer of Amantadine hydrochloride into breastmilk, but caution should still be used in nursing mothers.

Acute Overdose

Signs and symptoms of an overdose of Amantadine hydrochloride will vary depending on the amount of drug taken and can include symptoms such as confusion, agitation, and seizures. If an overdose is suspected, contact your doctor or Poison Control Center immediately.

Contraindication

Amantadine hydrochloride is contraindicated in patients with symptomatic hypotension, a history of seizures, and hypersensitivity to any component of the drug. It is also not recommended for use in children under 12 years of age.

Use Direction

Amantadine hydrochloride should be taken as prescribed by your doctor. Do not take more or less than the recommended dosage. Do not take the drug for longer than recommended. It is important to take the medication with food and to drink plenty of fluids.

Storage Condition

Amantadine hydrochloride should be stored at room temperature, away from direct sunlight and heat. The medication should be kept in a secure location, out of the reach of children and pets.

Volume of Distribution

The volume of distribution of Amantadine hydrochloride is 0.6–1.2 L/kg. It is rapidly distributed throughout the body, with concentrations in the brain and spinal cord being 5 to 7 times higher than those in the plasma.

Half Life

The half-life of Amantadine hydrochloride is approximately 11 – 19 hours. Most of the drug’s elimination is through the kidney.

Clearance

The clearance of Amantadine hydrochloride is approximately 400 – 800 mL/min. The drug is cleared from the body mainly by renal excretion, but it is also metabolized in the liver by the cytochrome P450 enzyme system.

See in details version Amantadine Hydrochloride also Amantadine Hydrochloride in bangla