Instruction for use: Topiramate 25mg

International Nonproprietary Name (INN): Topiramate

Pharmaceutic group: Antiepileptic

Presentation:

Tablets, film-coated, 25 mg, 100 mg ¹30.

Available with prescription

Indications for Topiramate

Topiramate is indicated for treatment of epilepsy, seizures or prevention of migraine attacks. The prescriptions are usually available from neurologists or specialists in epileptology or psychiatry.

Topiramate is a novel agent classified as a sulfamate substituted monosaccharide. Three pharmacological properties of topiramate are believed to contribute to its anticonvulsant activity. First, topiramate reduces the frequency at which action potentials are generated when neurons are subjected to a sustained depolarization indicative of a state-dependent blockade of voltagesensitive sodium channels. Second, topiramate markedly enhances the activity of GABA at some types of GABA receptors. Because the antiepileptic profile of topiramate differs markedly from that of the benzodiazepines, it may modulate a benzodiazepine-insensitive subtype of GABAA receptor. Third, topiramate antagonizes the ability of kainate to activate the kainate / AMPA subtype of excitatory amino acid (glutamate) receptors but has no apparent effect on the activity of N-methyl-D-aspartate (NMDA) at the NMDA receptor subtype. There are also alternative explanations of pharmacodynamics of this drug. We should take into account that the mechanism of action for Topiramate is still under discussion and research, in spite of widespread usage of the drug in medical practice (since 24 December 1996 in USA, for example).

Before prescribing this remedy, be sure to read carefully a specialist's leaflet.

Epilepsy - Monotherapy:

The recommended initial target dose for topiramate monotherapy in adults and children 6 years of age and older is 100 mg / day and the maximum recommended dose is 400 mg / day, administered in two divided doses, as needed and tolerated.

The recommended titration rate for topiramate monotherapy to 100 mg/day is:

If doses above 100 mg/day are required, the dose may be increased at weekly intervals in increments of 50 mg/day to a maximum of 400 mg/day. Dose and titration rate should be guided by clinical outcome. Some patients may benefit from a slower titration schedule. Daily doses above 400 mg have not been adequately studied.

Migraine - Adults

The usual total daily dose of Topiramate as treatment for prophylaxis of migraine headache is 100 mg/day administered in two divided doses. Dose and titration rate should be guided by clinical outcome. If required, longer intervals between dose adjustments can be used. No extra benefit has been demonstrated from the administration of doses higher than 100 mg/day and the incidence of some adverse events increases with increasing dose.

More information about Topiramate’s medical usage you can find in the approved leaflet (in Russian language only), which is included in each carton box with the product.

Trade name of the drug – Topiramate

Dosage Form: tablets

One film-coated tablet with a dosage of 25 mg contains:

Active ingredient: topiramate - 25 mg;

Excipients: Microcrystalline cellulose 31.4 mg 23.0 mg pregelatinized starch, colloidal silicon dioxide (Aerosil) 200 g magnesium stearate 0.4 mg Opadry II (1.28 mg of polyvinyl alcohol, 0.65 mg of macrogol, talc 0.47 mg, 0.23 mg of titanium dioxide, quinoline yellow colorant aluminum lake and 0.53 mg of dye sunset yellow aluminum lake 0.04 mg) 3.2 mg.

One film-coated tablet with a dosage of 100 mg contains:

Active ingredient: topiramate - 100 mg;

Excipients: microcrystalline cellulose 125.6 mg, 92.0 mg of pregelatinized starch, colloidal silicon dioxide (Aerosil) 800 mg magnesium stearate 1.6 mg Opadry II (polyvinyl alcohol, 5.12 mg, 2.58 mg macrogol, talc 1.89 mg, 0.93 mg of titanium dioxide, quinoline yellow colorant aluminum lake and 2.10 mg of dye sunset yellow aluminum lake 0.16 mg) 12.8 mg.

Pharmacotherapeutic group: Antiepileptic

ATX code: N03AX11

Pharmacological Properties of Topiramate

Pharmacodynamics

Topiramate is an antiepileptic agent belongs to a class of substituted monosaccharides sulfate. Does sodium channels and suppresses the occurrence of repetitive action potentials on a background of prolonged depolarization of the membrane of the neuron. It increases the activity of gamma-aminobutyric acid (GABA) in respect of certain subtypes of GABA receptors (including GABA receptors), and modulates the activity themselves GABAA receptor activation prevents kainate / AMPA (a-amino-3-hydroxy- 5-methylisoxazole-4-propionic acid) - glutamate receptors do not affect the activity of N-methyl-D-aspartate (NMDA) against NMDA-receptor subtype. These effects are dose-dependent topiramate in plasma concentrations of topiramate 1 to 200 mmol / l, with minimal activity in the range of 1 to 10 mol / l.

Additionally, topiramate inhibits the activity of certain isozymes of carbonic anhydrase (II-IV). According to the severity of the pharmacological effect of topiramate significantly inferior acetazolamide - known carbonic anhydrase inhibitor, so the action of topiramate it is not a major component of its antiepileptic activity.

Pharmacokinetics

After ingestion topiramate rapidly and well absorbed from the gastrointestinal tract. The bioavailability is about 81%. After oral administration of 400 mg of topiramate maximum plasma concentration (Cmax) 1,5 mcg / ml is reached within 2 hours. Food intake has no clinically significant effect on the bioavailability of topiramate. The value of Cmax after repeated oral administration of 100 mg topiramate twice daily averaged 6.76 ug / ml.

The pharmacokinetics of topiramate is linear, plasma clearance remains constant, and the area under the concentration / time curve (AUC) in the dose range from 100 to 400 mg increases proportionally with dose.

Contact with blood plasma proteins for topiramate is 13-17% in the range of plasma concentrations 0,5-250,0 ug / ml. After receiving a single dose of 1200 mg the average volume of distribution is 0,55-0,8 l / kg. The value of volume of distribution depends on gender: women - about 50% of the values observed in men, which is associated with higher levels of body fat women. Equilibrium concentration when taking topiramate in patients with normal renal function of patients achieved after 4-8 days. Penetrates into breast milk and through the placenta.

After oral administration, it is metabolized about 20% of the dose. It is metabolized by hydroxylation, hydrolysis and glyukuronirovaniya. However, in patients receiving concomitant therapy with antiepileptic drugs (AEDs) that are inducers of microsomal enzymes metabolism increased topiramate to 50%. From blood plasma, urine and feces six virtually inactive metabolites have been isolated and identified. At the same time taking inducers of cytochrome P450 isoenzymes level topiramate metabolism up to 50%.

The main route of excretion of unchanged topiramate (about 70%) and its metabolites are the kidneys. After oral administration, plasma clearance of topiramate was 20-30 ml / min. After repeated oral administration of 50 and 100 mg twice a day half-life (T1 / 2) from the blood plasma of topiramate on average 21 hours. Removed from the plasma by dialysis.

Pharmacokinetics in specific clinical situations. The renal and plasma clearance of topiramate with mild renal insufficiency (creatinine clearance (CC), more than 70 ml / min) is not altered. In moderate renal insufficiency (creatinine clearance 30-69 ml / min) renal and plasma clearance of topiramate is reduced by 42%, and in severe renal insufficiency (creatinine clearance less than 30 mL / min) renal and plasma clearance of topiramate is reduced by 54% or more.

In moderate and severe hepatic impairment the plasma clearance of topiramate is reduced by 20-30%.

In elderly patients without renal and hepatic impairment topiramate clearance was not changed.

The pharmacokinetics of topiramate in children, as in adults, is linear with clearance independent of dose; topiramate equilibrium concentration in blood plasma increases in proportion to the dose. Children topiramate increased clearance, and T1 / 2 is reduced, so when the same dose per 1 kg of body weight of topiramate concentration in plasma is lower in children than in adults. In children as in adults, antiepileptic drugs that induce hepatic microsomal enzymes cause a reduction in the concentration of topiramate in the plasma and increase the degree of its metabolism.

Indications for Topiramate

In monotherapy in adults and children 6 years of age with partial (with or without secondary generalization) or primary generalized tonic-clonic seizures.

In the combined therapy in adults and children over 3 years old with partial with secondary generalization or not, or generalized tonic-clonic seizures and for the treatment of seizures resulting from Lennox-Gastaut syndrome.

Prophylaxis of migraine in adults after a careful evaluation of all possible alternatives. Topiramate is not intended for the treatment of acute migraine attacks.

Contraindications for Topiramate

Hypersensitivity to topiramate, or to any other component of the drug; Children under 6 years of monotherapy, 3 years as part of combination therapy of epilepsy;

Children under the age of 18 years when used for migraine prophylaxis.

Prophylaxis of migraine in pregnant women or women of childbearing age not using effective contraception.

Precautions

Kidney failure, liver failure, hypercalciuria, nefrourolitiaz (including a history or family history).

Pregnancy and lactation

Special-controlled studies in which topiramate was used for the treatment of pregnant women have been conducted. There is evidence of a possible link between the use of topiramate during pregnancy and congenital malformations (eg, craniofacial defects ( "hare lip" / "palate"), hypospadias, the deficit of mass of the body of the fetus and newborn). These malformations were recorded as a monotherapy topiramate, and when it is applied simultaneously with other antiepileptic drugs (AEDs). These accounting pregnancies and topiramate monotherapy study results show an increase in the probability of children born underweight (less than 2500 g). The relationship of these cases with topiramate has not been established. Other studies indicate that the risk of teratogenic effects of combined treatment with other antiepileptic drugs can be higher than with monotherapy.

The use of topiramate during pregnancy is contraindicated. At the time of treatment is necessary to use effective contraceptive methods.

A limited number of observations of patients suggests that topiramate is excreted in breast milk, therefore the use of the drug during breast-feeding should be discontinued.

Women with childbearing potential, it is recommended to use effective methods of contraception and consider alternative treatments. When topiramate is used during pregnancy, or if the patient becomes pregnant while taking this drug, the doctor should warn her of the potential risk to the fetus.

Topiramate Dosage and Administration

Inside, regardless of meals. Tablets should not be divided.

it is recommended to start treatment with low doses with a subsequent increase to the effective dose to the optimal control of seizures. When used as monotherapy, it is necessary to take into account the possible impact of the abolition of concomitant antiepileptic drugs (AEDs) in the frequency of seizures. In cases where there is no need to cancel sharply PETs, their recommended dose be reduced gradually by reducing the dose by 1/3 every 2 weeks. If you cancel the drugs that are inducers of microsomal liver enzymes, topiramate plasma concentration will increase, which should be considered in the therapy.

Monotherapy

Adults:

Adults in the early monotherapy - 25 mg 1 time a day at bedtime for 1 week. Then the dose is increased at intervals of 1-2 weeks at 25-50 mg / day (daily dose is divided into 2 doses). At intolerance of such regimen, the dose is increased by a smaller amount, or over large intervals. The dose is adjusted depending on the effectiveness and tolerance of the therapy. The recommended initial target dose - 100-200 mg / day, the maximum daily dose should not exceed 500 mg monotherapy. Dosing recommendations apply to all adults, including elderly patients not suffering from kidney disease.

Children older than 6 years in monotherapy in the first week of treatment - 0.5-1 mg / kg body weight before bedtime. the dose was then increased at intervals of 1-2 weeks at 0.5-1 mg / kg per day (daily dose is divided into two steps). At intolerance of such regimen increase the dose more gradually or through long intervals between dose increase. The size of the dose and its rate of increase determined by the clinical efficacy and tolerability of therapy. The recommended dose range in monotherapy in children topiramate 100 mg / day, depending on the clinical efficacy (6-16 years old children is about 2 mg / kg / day).

In the combined therapy

Adults:

When administered in combination therapy with other antiepileptic drugs in adults the initial dose - 25-50 mg 1 time a day at bedtime for 1 week. Further dose increase of 25-50 mg weekly until the effective dose. The minimum effective dose is 200 mg / day, the average daily dose - 200-400 mg, the multiplicity of reception - 2 times a day. Dosages of more than 1600 mg per day have not been studied. The criterion for selection of the dose is the clinical effect and tolerability in certain patients, the effect can be achieved by taking the drug one time per day. Dosing recommendations apply to all adults, including elderly patients not suffering from kidney disease.

Children:

When administered in a combination anticonvulsant therapy in children older than 3 years, the recommended total daily dose - 5-9 mg / kg in 2 divided doses. dose selection begin with 25 mg / day (the rate of 3.1 mg / kg / day) at night for one week. Further the dose can be increased to 1.3 mg / kg for 1-2 weeks, and take 2 doses. The criterion for selection of the correct dose is stable clinical benefit and tolerability. The daily dose of 30 mg / kg is generally well tolerated.

Prophylaxis of migraine

The recommended total daily dose of 100 mg in 2 hours. Started treatment with a dose of 25 mg or less at bedtime for one week. Thereafter, the dosage is increased by 25 mg / cut at intervals of 1 week. At intolerance of such a regime the dose is increased by a smaller amount, or at long intervals. The dose is adjusted depending on the clinical effect. In some patients, a positive result is obtained at a daily dose of 50 mg / day. When applying a daily dose of 100 mg / day as an additional effect in preventing migraines not observed.

Patients with renal failure. For moderate patients (creatinine clearance less than 70 mL / min) and severe (CC less than 30 ml / min), the degree of renal failure recommended initial dose should be reduced by a factor of 2, and it should be increased by a smaller amount or at longer intervals. The dose is adjusted depending on the clinical effect. It will be appreciated that the achievement of the equilibrium concentration will require more time and ranges from 10 to 15 days after each dose increase topiramate preparation.

Patients requiring hemodialysis. Since topiramate may be removed by dialysis, the days of its daily dose is to be increased by 50%. Additional dose is divided into 2 parts and is introduced before the start of dialysis and after its completion. Additional dose may vary depending on the characteristics of the dialysis and equipment being used. The dose is adjusted depending on the clinical effect.

In patients with hepatic insufficiency drug Topiramate should be taken with caution due to a decrease in clearance of topiramate medical supervision.

In elderly patients, a dose adjustment is required.

removal of the drug

Antiepileptic drugs, including topiramate, should be withdrawn gradually to minimize the possibility of increasing the frequency of seizures, reducing the dose of 50-100 mg at intervals of 1 week in the treatment of epilepsy and by 25-50 in the application of topiramate for migraine prophylaxis. Children cancellation within 2-8 weeks. If medically necessary quick cancellation of topiramate, it is recommended to implement the control of the patient. The main route of elimination of topiramate and its metabolites is excreted unaltered by the kidneys. rate of excretion by the kidneys depending on renal function and is not dependent on age. In patients with moderately or highly severe renal function disorders in order to achieve equilibrium concentration in plasma may need 10-15 days compared to 4-8 days in patients with normal renal function.

As with other AEDs, the selection of a dose of topiramate drug scheme should focus on the therapeutic efficacy (ie the degree of reducing the frequency of seizures, no side effects) and should take into account the fact that in patients with impaired kidney function to determine the equilibrium concentration in plasma topiramate for each dose may need a longer time.

Side effect ofTopiramate

The frequency of side effects is classified in accordance with the recommendations of the World Health Organization: very often - at least 10%; often - at least 1% but less than 10%; infrequently - at least 0.1% but less than 1%; rarely - not less than 0.01% but less than 0.1%; very rarely - less than 0.01%, including isolated reports.

The most common adverse reactions (with the frequency ³5% compared with the placebo group, noted, at least one double-blind, controlled study): anorexia, decreased appetite, slowing of mental activity, depression, slurred speech, insomnia, impaired motor coordination, disturbance attention, dizziness, dysarthria, dysgeusia, hypoesthesia, lethargy, memory loss, nystagmus, paresthesia, somnolence, tremor, diplopia, blurred vision, diarrhea, nausea, fatigue, irritability, weight loss.

Children

Adverse reactions to the results of double-blind clinical studies in ³2 times more common in children than in adults: decreased appetite, increased appetite, hyperchloraemic acidosis, hypokalemia, conduct disorder, aggression, apathy, disturbance of sleep, suicidal ideation, disturbance of attention, drowsiness , violation of the daily rhythm of sleep, poor quality sleep, lacrimation increased, sinus bradycardia, poor general condition, gait disturbance.

Adverse reactions occurring in clinical trials exclusively at children: eosinophilia, psychomotor agitation, vertigo, vomiting, hyperthermia, fever, disturbance of learning.

overdose

Signs and symptoms of overdose: convulsions, drowsiness, speech disturbances, and vision, diplopia, impaired judgment, impaired coordination, dizziness, lethargy, stupor, hypotension, abdominal pain, dizziness, agitation and depression, metabolic acidosis. In most cases, clinical consequences were not severe, but were observed after an overdose deaths, using a mixture of several drugs, including topiramate. A case in overdose topiramate at a dose of 110 g, resulting in coma within 20-24 hours, and 3-4 days later full recovery.

Treatment: No specific antidote, being symptomatic therapy if necessary. It is necessary to immediately cause vomiting and stomach wash, increase your water intake. In in vitro studies have shown that activated carbon adsorbs topiramate.

Hemodialysis - the most efficient method of removing the body of topiramate. Patients are advised to increase the volume of adequate fluid intake.

Interaction

Effect of topiramate on the concentrations of other antiepileptic drugs (AEDs)

Simultaneous treatment with topiramate with other AEDs (phenytoin, carbamazepine, valproic acid, phenobarbital, primidone) has no effect on the value of their stable plasma concentrations, except in certain patients in whom the addition of topiramate to phenytoin may increase phenytoin plasma concentrations. This may be due to inhibition of a specific enzyme polymorphic isoform of cytochrome P450 (CYP2Cmeph). Therefore, each patient who receives phenytoin and which develop clinical signs or symptoms of toxicity, it is necessary to monitor the concentration of phenytoin in plasma.

In a study of the pharmacokinetics in patients with epilepsy the addition of topiramate to lamotrigine had no effect on the equilibrium concentration of the last at doses of 100-400 mg topiramate per day. In the course of treatment and after the abolition of lamotrigine (median dose of topiramate 327 mg / day), the equilibrium concentration of topiramate did not change.

Valproic acid: the combined use of topiramate and valproic acid in patients undergoing well each drug separately, accompanied by hyperammonemia with or without encephalopathy it. In most cases, the signs and symptoms disappear after withdrawal of one of the drugs. This adverse event is not due to pharmacokinetic interactions. Communication between the application and hyperammonemia topiramate alone or in combination with other drugs is not established. In a joint reception of topiramate and valproic acid can occur hypothermia (unintentional drop in body temperature below 35 ° C) in combination with hyperammonemia or independently. This phenomenon may occur after the beginning of co-administration of topiramate and valproic acid, and topiramate in increasing doses.

Other drug interactions

Digoxin: a study using single dose digoxin area under the concentration / time curve (AUC) in plasma digoxin while receiving topiramate was decreased by 12%. The clinical relevance of this observation is not clear. The appointment or termination of topiramate to patients receiving digoxin, special attention should be paid to the monitoring of digoxin serum concentrations.

CNS depressants: not recommended for concomitant use of topiramate with drugs, oppressive central nervous system function, as well as alcohol.

St. John's wort: when co-administered drugs topiramate and St. John's wort concentration of topiramate in plasma may be reduced, and as a result, the effectiveness of the drug may also decrease. Clinical studies of the interaction of the drug topiramate and preparations based on St. John's wort is not held.

Oral Contraceptives: study drug interactions with oral contraceptives which used a combination preparation containing norethisterone (1 mg) and ethinyl estradiol (35 .mu.g), topiramate at dosages of 50-800 MR daily had no significant efficacy on line and at doses of norethisterone 50- 200mg per day - the efficiency of ethinyl estradiol. Significant dose-dependent decrease in efficiency was observed at doses of ethinyl estradiol topiramate 200-800 mg per day. The clinical significance of these changes is not clear. The risk of reducing the effectiveness of contraceptives and increased breakthrough bleeding should be considered in patients taking oral contraceptives in combination with topiramate. Patients taking estrogensoderzhaschie contraceptives should inform your doctor about any changes in the timing and nature of menstruation. Contraceptive effectiveness can be reduced even in the absence of breakthrough bleeding.

Lithium: from healthy volunteers observed a decrease lithium AUC by 18% while receiving topiramate at a dose of 200 mg per day. In patients with manic-depressive psychosis use of topiramate at dosages up to 200 mg per day did not affect the pharmacokinetics of lithium, but at higher doses (up to 600 mg per day) lithium AUC was increased by 26%. With simultaneous use of topiramate and lithium should monitor the concentration of the latter in the blood plasma.

Risperidone: drug interaction studies performed with single and multiple doses of topiramate in healthy volunteers and patients with manic-depressive psychosis, gave the same results. With simultaneous application topiratama at doses of 250 or 400 mg per day of risperidone AUC received at doses 6.1 mg per day, respectively reduced by 16% and 33%. At the same pharmacokinetics of 9-hydroxyrisperidone is not changed, and pharmacokinetics of the total active ingredients (risperidone and 9-hydroxyrisperidone) changed insignificantly. Changes in the level of systemic exposure risperidona / 9-hydroxyrisperidone and topiramate had no clinically significant, and this interaction is unlikely to be of clinical significance.

Hydrochlorothiazide: drug interaction was evaluated in healthy volunteers in the separate and joint appointment of hydrochlorothiazide (25 mg) and topiramate (96 mg). The results showed that while taking topiramate and hydrochlorothiazide is an increase in the maximum concentration of topiramate by 27% and the area under the concentration curve of topiramate by 29%. The clinical relevance of these studies identified. Appointment of hydrochlorothiazide patients taking topiramate may require adjustment of the dose of topiramate. Pharmacokinetic parameters of hydrochlorothiazide has not been subjected to significant change with concomitant topiramate therapy.

With simultaneous application of topiramate, and showed an increase in Cmax of metformin and metformin AUC by 18 and 25%, respectively, whereas metformin clearance decreased 20%. Topiramate did not affect the time to reach Cmax of metformin in plasma. The clearance of topiramate while the use of metformin decreased. The extent of the revealed changes of clearance has not been studied. The clinical significance of the impact of metformin on the pharmacokinetics of topiramate is unclear. In the case of addition or cancellation of topiramate in patients receiving metformin should be carefully monitored for diabetes.

With simultaneous use of topiramate and pioglitazone have been identified reduction of AUC of pioglitazone by 15%, without changing the Cmax of pioglitazone. These changes were not statistically significant. Also for the active gidroksimetabolita pioglitazone decrease was observed Cmax and AUC by 13 and 16% respectively, while for the active ketometabolita been identified and decrease AUC and Cmax by 60%. The clinical significance of these data is not clear. In the case of a joint appointment of topiramate and pioglitazone should be closely monitored for diabetes.

In the application of glibenclamide (5 mg daily) alone or together with topiramate (150 mg daily) in patients with type 2 diabetes glibenclamide AUC was decreased by 25%. It was also reduced systemic exposure - 4-trans-3-gidroksiglibenklamida and cis gidroksiglibenklamida 13 and 15%, respectively. Glibenclamide did not affect the pharmacokinetics of topiramate in an equilibrium state. When administered to patients simultaneously glibenclamide and topiramate should take into account the possible pharmacokinetic interactions and carefully monitor the condition of patients for the evaluation of diabetes mellitus.

Other drugs: avoid simultaneous use of topiramate with drugs predisposing to nephrolithiasis, due to increased risk of stone formation in the kidneys.

special instructions for Topiramate

Antiepileptic drugs, including topiramate, should be withdrawn gradually to minimize the possibility of increasing the frequency of seizures. If for medical reasons need fast cancellation of topiramate, it is necessary to implement the control of the patient's condition.

As with any disease, the dose selection scheme should be guided by clinical effect and take account of the fact that in patients with impaired renal function to establish a stable topiramate plasma concentrations for each dose may need a longer time (10 to 15 days, as opposed to 4-8 days in patients with normal renal function). rate of excretion by the kidneys depending on renal function and is not dependent on age. When topiramate therapy is important adequate increase the volume of fluid consumed that can reduce the risk of nephrolithiasis, as well as the side effects that may occur under the influence of physical activity or elevated temperatures.

mood disorder / depression and suicide attempts.

In applying the drug topiramate observed increase in the incidence of mood disorders (including increasing aggressiveness), psychotic reactions and depression.

During clinical trials in patients with epilepsy, topiramate when used more often than in the placebo group, there have been cases associated with increased suicidal activity (suicidal ideation, suicide attempts and completed suicide) rate was 0.5% in patients treated with topiramate (46 of 8652 patients) and 0.2% of patients receiving placebo. The mechanism of this risk is unknown. When using topiramate should conduct a survey of patients for the presence of suicidal ideation and suicidal behavior. Upon detection of suicidal activity in patients consideration should be given appropriate treatment. Patients, their families, staff, patient care should be informed of the need to consult a physician in identifying signs of suicidal ideation and suicidal behavior.

Patients with any personality disorders need special monitoring, especially at the beginning of treatment topiramate.

nephrolithiasis

In patients with a predisposition to nefrorolitiazu increases the risk of kidney stones, which is necessary to prevent an adequate increase in the volume of fluid consumed. Risk factors for nephrolithiasis is a history of nephrolithiasis (including family), hypercalciuria, concomitant therapy with drugs that contribute to the development of nephrolithiasis.

Impaired Renal Function

Caution should be exercised when administering the drug topiramate in patients with renal insufficiency (creatinine clearance <70 mL / min). This is due to the fact that these patients have reduced clearance of the drug.

Abnormal liver function

Patients with hepatic impairment topiramate function should be cautious because of the possible reduction in clearance of the drug.

Myopia and secondary angle-closure glaucoma

When using topiramate described syndrome, including acute myopia with concomitant secondary angle-closure glaucoma. Symptoms include a sharp decline in visual acuity and / or pain in the eye. When the ophthalmic examination revealed myopia, flattening of the anterior chamber depth, flushing (redness) and increased intraocular pressure, and can be mydriasis. Described syndrome may be associated with supratsiliarnym effusion, which causes a shift of the lens and iris, and the development of secondary angle-closure glaucoma. Typically, the symptoms appear after the initial months of therapy. In contrast, primary open angle glaucoma, which is rarely detected in patients under 40 years, secondary angle-closure glaucoma associated with topiramate was observed in both children and adults. The treatment provides for the abolition of the drug topiramate, if the physician deems it appropriate, and taking appropriate measures to reduce intraocular pressure. Elevated intraocular pressure in the absence of adequate treatment can lead to serious complications, up to the loss of vision.

Metabolic acidosis

When using topiramate may occur hyperchloraemic not associated with a deficit of anions, metabolic acidosis. This reduction in the concentration of hydrocarbons serum is a consequence of the inhibitory effect of topiramate on renal carbonic anhydrase. In most cases the decrease in plasma concentration of hydrocarbons takes place at the beginning of topiramate, although this effect may occur at any time during treatment with topiramate. Reducing the concentration of hydrocarbons in plasma usually mild to moderate (mean plasma concentration of 4 mmol / l when applied in adult patient in a dose of 100 mg / day in children and in a dose of about 6 mg / kg / day). Reducing the concentration of hydrocarbons in plasma less than 10 mg / dL observed in rare cases. Some diseases or methods of treatment that predispose to the development of acidosis (e.g., renal disease, severe respiratory disease, status epilepticus, diarrhea, surgery, increased formation of ketone bodies in the body, use of certain drugs) may be additional factors enhancing bicarbonate-reducing the effect of topiramate. Chronic metabolic acidosis increases the risk of nephrolithiasis. In children, chronic metabolic acidosis can cause osteomalacia, and lead to a slowdown in the growth rate. The effect of topiramate on growth and possible complications of the skeletal system in children has not been systematically studied in children and adults.

When topiramate treatment should be carried out the necessary studies, including the identification of hydrocarbons concentration in the serum. If you have metabolic acidosis and its persistence, it is recommended to reduce the dose or stop taking the drug.

suralimentation

If the patient is losing weight while taking topiramate, it is necessary to consider the desirability of power supply.

When topiramate therapy may experience oligogidroza or anhidrosis. Reducing sweating and hyperthermia can occur in children exposed to high ambient temperatures. In this connection, it is very important to the adequate fluid intake capable to reduce the risk of side effects, including nephrolithiasis.

Laboratory findings

In 0.4% of patients taking topiramate observed hypokalemia, defined as a decrease in the concentration of potassium in the blood serum of below 3.5 mmol / l.

Information on the possible impact of the drug on the ability to drive and use machines

Topiramate has a weak or moderate influence on the ability to drive and use machines. Topiramate acts on the central nervous system and may cause drowsiness, dizziness and other symptoms. It can also cause blurred vision. These adverse reactions may represent a potential threat to patients in the management of their vehicles and operate machinery, especially in the period of the establishment of individual sensitivity to the drug. During the period of treatment must be careful when driving and using machinery.

Release form of Topiramate

Film-coated tablets 25 mg and 100 mg.

10 tablets in blisters of PVC film and aluminum foil printing patent or 100 tablets in a jar polymer.

At 1, 2, 3, 4, 5 contour cell packages or one bank, along with instructions for use are placed in a pile of cardboard.

Storage conditions of Topiramate

In a dry, dark place at a temperature no higher than 25 ° C.

Keep out of the reach of children.

Shelf life of Topiramate

2 years.

Do not use beyond the expiration date printed on the package.

Conditions of supply of Topiramate from pharmacies

With prescription.