Generic Symmetrel is an antiparkinsonian and antiviral agent. This drug belongs to tricyclic symmetric adamantanamine. It blocks glutamate NMDA receptors and thereby reduces the excessive stimulating effect of cortical glutamate neurons on the neostriatum, which develops on the background of dopamine deficiency. Amantadine, the main component, inhibits the NMDA receptors of the substantia nigra neurons, reduces the intake of Ca2 + in them, which reduces the possibility of destruction of these neurons. It mostly affects stiffness (rigidity and bradykinesia).
- Parkinson’s disease, parkinsonism syndrome (rigidity, tremor, hypokinesia);
- Shingles neuralgia caused by the Varicella zoster virus;
- Prevention (including in combination with vaccination) and treatment of influenza A.
How to take this medicine?
- For oral administration, a single dose is 100-200 mg. In the form of infusion, 200 mg for 3 hours is enough.
- The frequency and duration of use depend on the indications, the patient’s response to treatment, and the epidemiological situation.
- Maximum dose: oral administration – 600 mg/day.
Are there any side effects of Symmetrel?
- The central nervous system: headaches, depression, visual hallucinations, motor or mental agitation, convulsions, irritability, dizziness, sleep disorders, tremors, mental disorders accompanied by visual hallucinations, decreased visual acuity.
- The cardiovascular system: development or worsening of heart failure, orthostatic hypotension; rarely – arrhythmia, tachycardia.
- The digestive system: rarely – anorexia, nausea, constipation, dry mouth.
- The urinary system: in patients with prostatic hyperplasia – difficulty urinating; polyuria, nocturia.
- Dermatological reactions: dermatosis, the appearance of a bluish color of the skin of the upper and lower extremities (livedo reticularis).
Contraindications – what to tell your doctor?
There are the following contraindications: hepatic failure, chronic renal failure, psychosis (including history), thyrotoxicosis, epilepsy, angle-closure glaucoma, prostatic hyperplasia, arterial hypotension, chronic heart failure stage II-III, state of agitation, preddelirium, delirious psychosis, I trimester pregnancy, lactation, concomitant administration of triamterene and hydrochlorothiazide, hypersensitivity to amantadine. If you have some of these conditions, inform your doctor as fast as possible. Otherwise, there may appear severe health problems.
Is it possible to take Symmentrel during pregnancy and lactation?
During pregnancy, the use of amantadine is possible only under strict indications and medical supervision. It is contraindicated in the first trimester of pregnancy. If necessary, when lactating, better to stop breastfeeding.
Possible or impossible drug interactions
- This drug is possible to increase the side effects of antiparkinsonian drugs when taking with Symmetrel.
- The simultaneous use with thiazide diuretics may provoke the development of toxic effects of amantadine (ataxia, agitation, hallucinations), probably due to a decrease in its renal clearance.
- A case of acute confusion of consciousness in an elderly patient with simultaneous use with co-trimoxazole is described.
- The simultaneous use with quinine, quinidine may reduce the excretion of amantadine in the urine.
What more I need to know about this medicine?
This medicine is used in combination with levodopa, benzohexol for Parkinson’s disease. In terms of effectiveness, it is comparable to biperiden, trihexyphenidil in extrapyramidal disorders caused by neuroleptics in schizophrenic patients. For the prevention and treatment of influenza A, it is comparable in effectiveness to rimantadine, but causes more side effects.
Influence on the ability to drive vehicles and control mechanisms: during the period of treatment, one should not engage in activities that require a high concentration of attention and quick psychomotor reactions.
Abrupt withdrawal of the drug should be avoided.