Memantinol Coated 10mg N30 Tablets
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Active ingredients
Memantine
Release form
Pills
Composition
One vial contains the active substance - Retinalamin 5 mg (a complex of water-soluble polypeptide fractions), the excipient - glycine 17 mg (stabilizer).
Pharmacological effect
Memantine is a potential-dependent noncompetitive NMDA receptor inhibitor with moderate affinity for it. It modulates the action of pathologically elevated tonic glutamate content, which can lead to neuronal dysfunction.
Pharmacokinetics
After ingestion is quickly and completely absorbed. Cmax in plasma is 3–8 h after administration. Pharmacokinetics is linear in the dose range from 10 to 40 mg. A daily intake of a daily dose of 20 mg leads to plasma Css from 70 to 150 ng / ml (0.5–1 mcmol) with pronounced individual variations. Vd is about 10 l / kg. About 45% of memantine is bound to plasma proteins. In normal renal function, cumulation of the drug is not observed. About 80% of memantine is present in the circulating blood as an unchanged compound. The main metabolites are N-3,5-dimethylgludantan, a mixture of 4- and 6-hydroxy-memantine isomers and 1-nitroso-3,5-dimethyl-adamantane. None of these metabolites has antagonistic activity towards NMDA receptors. The involvement of cytochrome P450 in metabolism in in vitro studies was not identified. In studies with the admission of 14C-memantine, it was orally detected that, on average, 84% of the dose was eliminated within 20 days, with more than 99% of the drug excreted by the kidneys. Memantine is excreted primarily by the kidneys. Withdrawal occurs mono-exponentially, T1 / 2 ranges from 60 to 100 hours. In studies in volunteers with normal renal function, total clearance was 170 ml / min / 1.73 m2, part of the total renal clearance was achieved due to secretion by the renal tubules. Renal excretion also includes tubular reabsorption, which may be accomplished through cationic transport proteins. The rate of renal elimination under alkaline conditions of urine may decrease by a factor of 7–9. Alkalization of urine can be a consequence of a drastic change in nutrition, for example, a transition from the use of predominantly meat products to vegetarianism, or the intensive use of alkaline gastric buffers. The relationship of pharmacokinetics and pharmacodynamics.When receiving a maintenance dose of 20 mg / day, the level of concentration of memantine in the cerebrospinal fluid corresponds to the value of Ki (inhibition constant), which for memantine is 0.5 μmol in the area of the frontal cortex of the brain in humans.
Indications
Dementia is moderate to severe in Alzheimer's disease.
Contraindications
Individual hypersensitivity to memantine or any of the components that make up the drug; pregnancy and breastfeeding; age up to 18 years; lactase deficiency, lactose intolerance, glucose-galactose malabsorption syndrome.
Use during pregnancy and lactation
Contraindicated in pregnancy, because There are no clinical data on the effect of memantine on the course of pregnancy. Studies conducted on animals indicate the possibility of the drug to cause intrauterine growth retardation at the level of exposure to identical or slightly superior concentrations of memantine compared with those in humans. The potential risk to humans is unknown. It is not known whether memantine is excreted into breast milk, so women who take memantine should refrain from breastfeeding.
Dosage and administration
The drug should be taken orally once a day and always at the same time, regardless of the meal. Adults: Titration. Maximum daily dose of 20 mg / day. In order to reduce the risk of adverse reactions, the dose of the drug is titrated by successively increasing by 5 mg every week for the first three weeks. Starting from the 4th week, the patient is prescribed memantine intake in a dose of 20 mg / day (two pills of 10 mg). The recommended maintenance dose of 20 mg per day.
Side effects
In clinical studies with moderate to severe dementia, the overall incidence of adverse reactions when taking memantine was not different from that of taking placebo. Very rarely: Convulsions Infrequently: Fungal infections, Confusion of consciousness, hallucinations (in patients with Alzheimer's disease at the stage of severe dementia), gait disturbance, Venous thrombosis / thromboembolism, Nausea, vomiting, Fatigue; often - hypersensitivity to the components of the drug, drowsiness, dizziness, imbalance, high blood pressure, shortness of breath, constipation, elevated liver function tests, headache; frequency not established - Psychotic reactions (in the period of post-registration experience of using memantine), Pancreatitis, Hepatitis.
Overdose
There are limited data on overdose obtained during clinical trials and post-registration experience in the use of memantine. Symptoms: with a relatively large overdose (200 mg once or 105 mg / day for 3 days) fatigue, weakness and / or diarrhea or symptoms were absent. In case of overdose in a dose of less than 140 mg once or receiving an unknown dose, patients experienced adverse reactions from the CNS - confusion, hypersomnia, drowsiness, dizziness, agitation, aggression, hallucinations, gait disturbance and / or from the digestive system - vomiting, diarrhea . In the most severe case of overdose, the patient survived after taking a dose of 2000 mg of memantine, he had adverse reactions from the central nervous system (coma for 10 days, then diplopia and agitation). The patient received symptomatic treatment and plasmapheresis. The patient recovered without further complications. In another case of severe overdose, the patient survived and recovered after taking memantine at a dose of 400 mg once. The patient had adverse reactions from the central nervous system - anxiety, psychosis, visual hallucinations, lowering the threshold of convulsive readiness, drowsiness, stupor and loss of consciousness. Treatment: symptomatic. It is necessary to conduct standard therapeutic measures aimed at removing substances from the stomach, such as washing the stomach, the appointment of activated carbon, acidification of urine, it is possible to conduct forced diuresis. There is no specific antidote.
Interaction with other drugs
With simultaneous use with levodopa preparations, dopamine receptor agonists, anticholinergic drugs, the action of the latter can be enhanced. With simultaneous use with barbiturates, neuroleptics, the effect of the latter may be reduced. With simultaneous use with dantrolen or baclofen, as well as with antispasmodics, their effect may change (increase or decrease), therefore the doses of drugs should be adjusted. The simultaneous use of memantine with amantadine due to the risk of developing psychosis should be avoided. Memantine and amantadine belong to the group of NMDA receptor antagonists. The risk of developing psychosis is also increased when used simultaneously with ketamine, dextromethorphan and phenytoin.When taken simultaneously with cimetidine, ranitidine, procainamide, quinidine, quinine and nicotine, plasma memantine concentrations may increase. It is possible to reduce the level of hydrochlorothiazide while taking it with memantine by increasing its elimination from the body. Perhaps an increase in INR in patients who simultaneously take oral indirect anticoagulants (warfarin). It is recommended to constantly monitor the MF or INR Simultaneous use with antidepressants, SSRIs and MAO inhibitors requires careful monitoring of patients. According to pharmacokinetic studies, in young healthy volunteers with a single simultaneous intake of memantine with glyburide / metformin or donepezil, the effects of drug interactions were not identified. Clinical studies also did not reveal the effect of memantine on the pharmacokinetics of galantamine in young healthy volunteers. In in vitro studies, memantine did not inhibit the isoenzymes of CYP1A2, CYP2A6, CYP2C9, CYP2D6, CYP2E1, CYP3A, monooxygenase, containing flavin, epoxyhydrolase, or sulfation.
special instructions
It is recommended to be used with caution in patients with thyrotoxicosis, epilepsy, convulsions (including history), as well as in patients with a predisposition to epilepsy. The simultaneous use of antagonists of NMDA receptors (amantadine, ketamine, dextromethorphan) and memantine should be avoided. These compounds act on the same receptor system as memantine, in connection with which side reactions (mainly from the CNS) can occur more often and be more pronounced. Taking into account the slowing down of memantine in patients with alkaline urine conditions, patients with factors that influence the increase in urine pH need to be more closely monitored (abrupt diet change, for example, when switching from predominantly meat products to vegetarianism, intensive consumption of alkaline gastric buffers), as well as in cases of renal tubular acidosis or severe urinary tract infection caused by bacteria of the genus Proteus. The data on the administration of memantine in patients with myocardial infarction (in history), with chronic heart failure of the III – IV functional class (according to the NYHA classification) and uncontrolled arterial hypertension are limited, therefore careful medical monitoring of such patients is necessary. The influence of the drug for medical use on the ability to drive vehicles, mechanisms.In patients with Alzheimer's disease at the stage of moderate and severe dementia, the ability to drive vehicles and manage complex mechanisms is usually impaired. In addition, memantine can cause a change in the reaction rate, so patients should refrain from driving or working with complex mechanisms.