Normokinesin pills 25mg, 112pcs

Composition

of 1 tab. : tetrabenazine 25 mg. Auxiliary substances: pre-gelatinized corn starch-33 mg, lactose monohydrate-64.05 mg, talc (micronized) – 2 mg, iron oxide yellow dye (E172) – 0.2 mg, magnesium stearate-0.75 mg

Pharmacological action

A synthetic derivative of benzoquinolysine, it has a specific effect on the central nervous system similar to reserpine, but unlike the latter, tetrabenazine has insignificant peripheral activity and a shorter duration of action. Tetrabenazine disrupts the metabolism of biogenic amines such as serotonin and norepinephrine in the brain. Inhibits the reuptake of monoamines in the nerve endings of presynaptic neurons of the central nervous system, which leads to a decrease in the amount of monoamines, including dopamine in the brain. Dopamine depletion leads to hypokinesia, which reduces the severity of chorea. In synaptic nerve endings, tetrabenazine inhibits monoamine reuptake by reversible and short-term binding of the vesicular monoamine transporter (VMAT). VMAT 2 transports monoamines to peripheral and central neurons, while VMAT 1 regulates transport in peripheral chromaffin tissues. Tetrabenazine has a higher affinity for VMAT 2 than for VMAT 1, so the drug has a short-term insignificant peripheral effect. Pharmacokineticatetrabenazine has a low and unstable bioavailability, is actively metabolized during the first passage through the liver. The main metabolite is hydroxytetrabenazine, which is formed by reduction. A small amount of tetrabenazine in unchanged form is excreted in the urine. Since hydroxytetrabenazine is as active as tetrabenazine in the release of cerebral amines, it is presumably the dominant drug. In patients with mild to moderate hepatic impairment, exposure to both T1/2 tetrabenazine and hydroxytetrabenazine increases (from 5 to 9 points on the Child-Pugh scale). The use of tetrabenazine in patients with severe hepatic impairment has not been studied.

Indications

Hyperkinetic motor disorders in Huntington’s chorea.

Contraindications

Hypersensitivity to tetrabenazine or other components of the drug; concomitant use with reserpine; concomitant use of MAO inhibitors; presence of hypokinetic / rigid syndrome (Parkinsonism); depression; pregnancy and lactation; pheochromocytoma; prolactin-dependent tumors, such as pituitary tumors or breast cancer; children under 18 years of age (due to the lack of proven efficacy and safety of use). With caution: impaired liver function; impaired renal function.

Side effects

Determination of the frequency of adverse reactions: very common (≥1/10), common (≥1/100 to <1/10), infrequent (≥1/1000 to <1/100), rare (≥1/10,000 to <1/1000), very rare (Mental disorders: very often – depression; often-anxiety, insomnia, confusion; frequency not established-disorientation, increased nervous excitability. From the nervous system: very often – drowsiness (when taken in high doses), Parkinsonism (when taken in high doses); infrequently-changes in the level of consciousness; rarely-NMS; frequency is not established – ataxia, akathisia, dystopia, dizziness, amnesia. From the cardiovascular system: often-arterial hypotension; frequency not established-bradycardia. From the digestive system: often-dysphagia, nausea, vomiting, diarrhea, constipation; frequency not established-epigastric pain, dry mouth. Musculoskeletal disorders: infrequently – severe extrapyramidal symptoms, including muscle rigidity, autonomic dysfunction; very rarely-skeletal muscle damage. General reactions: infrequently-hyperthermia. Overdose: drowsiness, sweating, hypotension, hypothermia.

Interaction

Tetrabenazine should not be used simultaneously with reserpine, as it may block the action of reserpine. Tetrabenazine should not be used concomitantly with MAO inhibitors. Levodopa should be administered with caution when treated with tetrabenazine, since tetrabenazine suppresses the effect of levodopa and thereby weakens its effectiveness. Concomitant use with tricyclic antidepressants, alcohol, opioids, beta-blockers, antihypertensive drugs, sleeping pills and neuroleptics is not recommended. A targeted study of the interaction of tetrabenazine in vivo has not been conducted, so the enzymes involved in its metabolism are partially unknown. In vitro studies have shown that tetrabenazine can be an inhibitor of the CYP2D6 isoenzyme and, as a result, cause an increase in the plasma concentration of drugs metabolized with the participation of the CYP2D6 isoenzyme. Inhibitors of the CYP2D6 isoenzyme (for example, fluoxetine, paroxetine, terbinafine, moclobemide and quinidine) can lead to an increase in the plasma concentration of the active metabolite of dihydrotetrabenazine, so they should be used with caution when taken together. In this case, it may be necessary to reduce the dose of tetrabenazine. Tetrabenazine should be used with caution with drugs that increase the QTc interval, especially with antipsychotic drugs (for example, chlorpromazine, thioridazine), antibiotics (for example, gatifloxacin, moxifloxacin) and antiarrhythmic drugs of class Ia and III (for example, quinidine, procainamide, amiodarone, sotalol).

How to take, course of use and dosage

Apply inside. Treatment should be carried out under the supervision of a doctor who has experience in the treatment of hyperkinetic disorders. The recommended starting dose for adults with Huntington’s chorea is 12.5 mg 1 to 3 times a day. Further, the dose can be increased once every 3-4 days by 12.5 mg until the optimal therapeutic effect is achieved or until side effects (sedation, parkinsonism, depression) occur. The maximum dose is 200 mg / day. If there is no therapeutic effect when taking tetrabenazine at the maximum daily dose for 7 days, it is unlikely that an increase in the dose or an extension of the treatment period will have the necessary effect. In elderly patients, tetrabenazine is recommended to be used at a standard dose. It is possible to limit the dose taken by the appearance of symptoms of Parkinsonism. Patients with mild to moderate hepatic impairment are recommended to take 1/2 of the initial dose with gradual slow titration to the optimal therapeutic dose. The effect of the drug in patients with severe hepatic impairment has not been studied, so in such cases it is recommended to use the drug with caution. Studies in patients with impaired renal function have not been conducted. Treatment of this category of patients should be carried out with caution.

Special instructions

Tetrabenazine should not be used in patients with rare hereditary problems such as galactose intolerance, lactase deficiency, or glucose – galactose malabsorption. Dose-dependent adverse reactions such as sedation, depression, and hypokinetic/rigid syndrome (Parkinsonism) may occur. In this case, the dose should be reduced or treatment with tetrabenazine should be discontinued. MAO inhibitors are contraindicated and should be discontinued 14 days before starting tetrabepazine treatment. Tetrabenazine should be used with caution in patients with impaired liver function. NMS is a rare complication of therapy and most often occurs at the beginning of treatment, in response to changes in the dose or after prolonged treatment, as well as after abrupt withdrawal of tetrabenazine. The main symptoms of this disease are mental changes, rigidity, hyperthermia, autonomic disorders (sweating and fluctuations in blood pressure) and elevated CPK levels. If you suspect the presence of NMS, you should immediately stop using tetrabenazine and prescribe appropriate treatment. Tetrabenazine causes a small increase (up to 8 msec) the QT interval. Tetrabenazine should be used with caution in combination with other medications that prolong the QTc interval, in patients with congenital long QT syndrome and in patients with a history of cardiac arrhythmias. Use in pediatricsclinical studies of the effectiveness and safety of the drug in children have not been conducted. Tetrabenazine is not recommended for children. Effects on the ability to drive vehicles and work with mechanicsmitetrabenazine can cause drowsiness and, therefore, can affect the performance of tasks that require increased attention to varying degrees, depending on the dose and individual tolerance.

Active ingredient

Tetrabenazine

Conditions of release from pharmacies

By prescription

Purpose

Adult Doctor’s prescription