Chemical properties
This drug is an antiviral and at the same time antiparkinsonian drug. According to its chemical structure, the substance is tricyclic aminoadamantane .
Amantadine is available as a sulfate , glucuronide , or hydrochloride . The hydrochloride is a white or white with a yellow tint, a coarse crystalline powder. The compound is highly soluble in water and alcohols, and practically insoluble in ether .
Amantadine was first used as an antiviral drug in 67 of the 20th century. of Parkinson's disease was discovered . rabies was cured using this drug ( Milwaukee protocol ). The patient was put into an induced coma and 7 days later tests showed the absence of the virus.
Pharmacodynamics and pharmacokinetics
The mechanism of action of Amantadine is not fully understood. It is assumed that the drug stimulates the processes of removing dopamine from its neuronal depots, thereby increasing the degree of sensitivity of specific receptors to this neurotransmitter . As a result, if there is a decrease in the intensity of dopamine in the basal ganglia , the drug creates conditions that normalize neurophysiological processes . There is an opinion that additional lek. the drug can inhibit the generation of nerve impulses in motor neurons of the central nervous system, acting as a weak antagonist of NMDA receptors .
The antiviral effect of the drug is explained by its ability to block the penetration of virus A into a living cell.
After oral administration, the active substance is well and quickly absorbed in the gastrointestinal tract. The maximum concentration of Amantadine in the blood plasma can be noted within 4 hours after administration. The drug overcomes the blood-brain and placental barriers and is excreted in breast milk. The half-life of the drug is about 15 hours. The substance is excreted unchanged through the kidneys.
Features of application
Pregnant
Amantadine is contraindicated for pregnant women and women planning pregnancy. The drug is contraindicated during breastfeeding as it passes into breast milk. If it is necessary to use the drug, breastfeeding should be discontinued.
Children
There is insufficient experience with the use of amantadine in children, so the drug is not used in this age category.
Drivers
Amantadine may reduce concentration and reaction speed, cause dizziness, and decreased visual acuity, so patients should be warned about the potential danger when driving or operating other machinery.
Indications for use
The drug is prescribed:
- for Parkinson's disease ;
- for the treatment of rigid and akinetic forms of parkinsonism ;
- in case of loss of consciousness as a result of TBI;
- to eliminate extrapyramidal disorders associated with taking medications (for example, antipsychotics );
- with neuralgia accompanying herpes zoster ;
- if the patient needs to be slowly brought out of anesthesia;
- as a prophylactic against influenza A ;
- for the treatment of influenza A as part of complex therapy.
Contraindications
The medicine is contraindicated:
- in the presence of allergic reactions to the active substance;
- if the patient has previously experienced psychosis ;
- patients with epilepsy ;
- with thyrotoxicosis ;
- patients with glaucoma ;
- for prostatic hyperplasia ;
- pregnant women;
- for severe liver and kidney diseases;
- while breastfeeding.
Caution is recommended:
- in the treatment of patients with congestive heart failure ;
- patients with allergic dermatitis ;
- with strong psychomotor agitation;
- patients with renal and liver failure ;
- for hallucinations and confusion .
Amantadine
Treatment with amantadine should not be stopped suddenly, as this may worsen the course of the disease.
Patients with cardiovascular diseases should be under constant medical supervision if amantadine is prescribed.
Before starting, as well as after 1 and 3 weeks of treatment, an ECG should be monitored, and in the future, an ECG should be carried out at least once a year. Treatment should not be started or should be stopped if the initial QTc value is >420 ms, if the QT increases by >60 ms during treatment with the drug, or if the QTc value is >480 ms, as well as in patients with visible waves on the ECG.
Patients at risk of electrolyte imbalance, particularly those on diuretic therapy, with frequent vomiting and/or diarrhea, patients using insulin, or those with renal or anorexic disorders should have laboratory parameters monitored and, if necessary, appropriate replacement of electrolytes, especially potassium and magnesium. If symptoms such as palpitations, dizziness, or fainting occur, treatment with amantadine should be stopped immediately and the patient should be monitored for 24 hours for QT prolongation. In individuals with a pacemaker, accurate determination of QT time is not possible, so the decision to use amantadine should be made individually after consultation with a cardiologist. Treatment with amantadine should not be stopped suddenly, as this may lead to a worsening of Parkinson's disease and the appearance of symptoms. characteristic of neuroleptic malignant syndrome, as well as the development of cognitive impairment, such as catatonia, confusion, disorientation, deterioration of mental state, delirium.
Individuals taking antipsychotics and amantadine concomitantly are at risk of developing neuroleptic malignant syndrome if amantadine is suddenly stopped.
In some patients, with prolonged use of the drug, peripheral edema may occur. This should be considered for persons with chronic heart failure.
Suicide attempts and suicidal ideation have been reported in patients while using amantadine. In order to prevent the occurrence of suicidal thoughts and intentions, the drug must be prescribed in minimal effective doses.
Side effects
During treatment with Amantadine, the following may occur:
- headache, hallucinations , convulsions , depression , psychomotor agitation;
- dizziness, insomnia , tremor , blurred vision, increased irritability and sensitivity;
- decreased blood pressure, heart failure;
- constipation, nausea, dry oral mucosa;
- nocturia , retention and difficulty urinating, polyuria (with prostatic hyperplasia);
- dermatosis , a blue tint to the skin on the extremities;
- rarely – anorexia , tachycardia , cardiac arrhythmia .
Amantadine, instructions for use (Method and dosage)
The drug is prescribed orally. After eating.
The initial daily dosage for adults is 0.1 grams. If indicated, 7 days after the start of treatment, the dosage can be increased to 0.2 g per day. The maximum amount of the drug that can be taken during the day is 0.4 grams.
Due to the fact that the medicine can stimulate the central nervous system, it is not recommended to use it later than 4 pm. In case of renal failure, the dosage should be reduced and the interval between doses increased.
Most often, therapy is carried out in combination with other medications ( alpha-dopa and anticholinergics ). The duration of treatment is determined by the doctor.
For the prevention or treatment of influenza, 0.2 mg of the drug is prescribed for 10 days.
The substance is administered intravenously at 0.2 grams several times a day. The infusion rate is low, no more than 50-60 drops per minute, the procedure is carried out over 3 hours.
To treat viral eye diseases, a 0.5% aqueous solution is instilled into the conjunctival sac 5 times a day, gradually reducing the dose to 1-2 times a day. The course of treatment ranges from 5 to 15 days.
Mode of application
Tablets should be taken by adults orally, with a small amount of liquid, after meals, preferably in the morning and/or afternoon. Due to the possible activating effect on the central nervous system (CNS), it is recommended to take the last dose no later than the sixteenth hour.
Single and daily dose
By following the above measures and taking into account contraindications, you can prevent a life-threatening adverse reaction - chaotic polymorphic ventricular tachycardia.
Treatment of patients with Parkinson's syndrome and motor activity disorders caused by the use of drugs should be carried out gradually, observing the dosage in accordance with the therapeutic effect.
Treatment should begin with taking one tablet (100 mg of amantadine sulfate) of the drug "Amantin" per day in the first 4-7 days, followed by increasing the daily dose by one tablet once a week until an effective therapeutic dose is achieved.
The usually effective dose is 1-3 tablets twice a day (200-600 mg amantadine sulfate).
For elderly patients, in particular in states of agitation, confusion or delirium syndromes, a daily dose of 100 mg (one tablet) is recommended. If this dose is not effective, it can be carefully increased to 200 mg per day under the supervision of a physician.
When combined with other antiparkinsonian drugs, the dose should be selected individually.
For patients previously treated with amantadine injection, the initial dose should be higher.
If parkinsonian symptoms sharply worsen during an akinetic crisis, it is necessary to prescribe the administration of amantadine sulfate solution.
The duration of treatment depends on the nature and severity of the disease and is determined by the doctor. Patients should not interrupt treatment on their own.
Abrupt discontinuation of treatment should be avoided as it may result in increased extrapyramidal symptoms in patients with Parkinson's disease, which sometimes include an akinetic crisis, and the effect of discontinuation may sometimes manifest as delirium.
Interaction
When combined with the drug, side effects may increase when using other drugs for parkinsonism .
The simultaneous use of the drug and thiazide diuretics can lead to a decrease in the renal clearance of Amantadine and the development of toxic effects, hallucinations , ataxia , and severe psychomotor agitation.
Quinidine and quinine can slow down the process of excretion of the drug in the urine.
Isolated cases of confusion in elderly patients have been described when combining the drug with co-trimoxazole .
Overdose
The possibility of multiple intoxication, such as taking more than one drug for suicide purposes, should always be considered.
Symptoms
A significant place in an overdose of amantadine is occupied by the symptoms of acute toxic psychosis in the form of confusion with visual hallucinations, which sometimes include coma and myoclonus and can be observed after the simultaneous use of amantadine and other antiparkinsonian drugs. Excessive agitation, tremor, ataxia, blurred vision, lethargy, depression, dysarthria, neuromuscular disorders, hyperreflexia, motor restlessness, convulsions, extrapyramidal phenomena, torsion spasms, dilated pupils, dysphagia, confusion, disorientation, delirium, myoclonus, nausea, vomiting, dry mouth, hyperventilation, pulmonary edema, respiratory failure, respiratory distress syndrome, hypertension, cardiac arrhythmia, tachycardia, angina attacks, cardiac arrest. Possible renal dysfunction, including increased urea nitrogen and decreased creatinine clearance, urinary retention.
Treatment
No specific drug treatment or antidote is known. To prevent absorption of the drug, it is necessary to induce vomiting and/or lavage the stomach (if the patient is conscious), and use activated charcoal. In case of life-threatening intoxication, resuscitation measures are necessary. It is necessary to take therapeutic measures, ensure the maintenance of vital body functions, adequate hydration, possibly sedation, measures against seizures and arrhythmias.
Reviews
Reviews of the drug are mostly positive; adverse reactions develop infrequently. Some reviews about the drug:
- “... I am 49 years old and suffer from parkinsonism. The doctor prescribed me to take the medicine twice a day, I have been taking it for 2 months. Now I feel better, the tremors have decreased, I have increased strength and confidence, I haven’t noticed any side effects yet”;
- “... This drug helps me well against Parkinson’s disease. I take it in combination with madopar. My gait has become more stable, I stopped constantly falling, and now I can almost completely take care of myself.”
Note!
Description of the drug Amantin table. p/o 100 mg No. 60 on this page is a simplified author’s version of the apteka911 website, created on the basis of the instructions for use.
Before purchasing or using the drug, you should consult your doctor and read the manufacturer's original instructions (attached to each package of the drug). Information about the drug is provided for informational purposes only and should not be used as a guide to self-medication. Only a doctor can decide to prescribe the drug, as well as determine the dose and methods of its use.
