Gabapentin 300mg Capsules N50
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Description
Gabapentin canon - capsules of green. The contents of the capsules are white or almost white. Lumps are allowed, which easily turn into powder when pressed with a glass rod.
Active ingredients
Gabapentin
Composition
Gabapentin, calcium stearate, sodium carboxymethyl starch, microcrystalline cellulose.
Pharmacological effect
The exact mechanism of action of gabapentin is not known. The chemical structure of gabapentin is similar to the structure of the neurotransmitter GABA (gamma-aminobutyric acid), but its mechanism of action differs from other active substances that interact with GABA synapses, such as valproate, barbiturates, benzodiazepines, GABA inhibitors, transaminase inhibitors, GABA reuptake inhibitors, agonists GABA and prodrugs of GABA. In in vitro studies with radiolabeled gabapentin, new areas of drug binding to proteins, including the neocortex and hippocampus, were found in the rat brain, which may be related to the anticonvulsant and analgesic activity of gabapentin and its derivatives. It was found that the binding site of gabapentin is the α-2-δ (alpha-2-delta) subunit of voltage-dependent calcium channels. At clinically significant concentrations, gabapentin does not bind to other common receptors for drugs and neurotransmitters present in the brain, including GABA, GABAc, benzodiazepine, glutamate, glycine and N-methyl-D-aspartate receptors. In vitro, gabapentin does not interact with sodium channels, which distinguishes it from phenytoin and carbamazepine. In a number of in vitro test systems, the use of gabapentin led to a partial decrease in the response to the glutamate agonist N-methyl-D-aspartate (NMDA), but only at a concentration in excess of 100 μmol / l, which is unattainable in vivo. In vitro, gabapentin leads to a slight decrease in the release of monoamine neurotransmitters.
Pharmacokinetics
After ingestion, the maximum concentration of gabapentin in the blood plasma is reached within 2-3 hours. The bioavailability of gabapentin tends to decrease with increasing dose of the drug.Absolute bioavailability when taking capsules dosage of 300 mg is approximately 60%. Food, including those with a high fat content, does not have a clinically significant effect on the parameters of gabapentin pharmacokinetics. The pharmacokinetics of gabapentin does not change with repeated use of the drug. Gabapentin does not bind to plasma proteins, and its volume of distribution is 57.7 l. In patients with epilepsy, the concentration of gabapentin in the cerebrospinal fluid (CSF) is approximately 20% of the minimum equilibrium plasma concentration. Gabapentin is excreted in breast milk. Gabapentin is excreted unchanged exclusively by renal excretion. The half-life of gabapentin does not depend on the dose taken and averages from 5 to 7 hours.
Indications
Treatment of neuropathic pain in adults aged 18 years and older (efficacy and safety in patients under the age of 18 years have not been established). Monotherapy of partial seizures with secondary generalization and without it in adults and children aged 12 years and older (efficacy and safety of monotherapy in children under the age of 12 years have not been established). As an additional agent in the treatment of partial seizures with secondary generalization and without it in adults and children aged 3 years and older (safety and efficacy of additional gabapentin therapy in children aged less than 3 years have not been established).
Contraindications
Hypersensitivity to gabapentin or auxiliary components of the drug, Children up to 18 years of age in the treatment of neuropathic pain, Children up to 12 years of age with partial therapy of partial seizures with and without secondary generalization, Children of up to 3 years of age when used as an additional agent in the treatment of partial seizures with secondary generalization and without it.
Precautionary measures
Renal failure.
Use during pregnancy and lactation
The risk of having children with congenital anomalies in mothers who are being treated with anticonvulsant drugs increases by a factor of 2-3. Most often observed cleft lip and palate, malformations of the cardiovascular system and defects of the neural tube. However, taking multiple anticonvulsants may be associated with a greater risk of malformations than in the case of monotherapy. Therefore, if possible, use one of the anticonvulsants.Women of childbearing age, as well as all women who may become pregnant, should consult a qualified professional. If a woman is planning a pregnancy, the need to continue anticonvulsant therapy should be assessed again. At the same time, anticonvulsant drugs should not be canceled abruptly, as this may lead to the resumption of seizures with serious consequences for the mother and child. In rare cases, children whose mothers suffer from epilepsy have a developmental delay. It is not possible to determine whether developmental delay is associated with genetic or social factors, maternal illness or anticonvulsant therapy. Gabapentin is excreted in breast milk, its effect on the infant being fed is unknown, so during breastfeeding gabapentin should be prescribed only if the benefit to the mother clearly outweighs the risk to the infant. In animal studies, gabapentin has no effect on fertility.
Dosage and administration
Inside, regardless of the meal. The dosage is prescribed by the attending physician. If it is necessary to reduce the dose, discontinue the drug or replace it with an alternative means, this should be done gradually over at least one week. Adults and children over the age of 12: the effective dose is from 900 to 3600 mg / day. Children aged 3-12 years: the initial dose of the drug varies from 10 to 15 mg / kg / day, which is prescribed in equal doses 3 times a day and increased to an effective amount in about 3 days.
Side effects
Infectious and parasitic diseases: very often - viral infections, often - pneumonia, respiratory tract infection, urinary tract infection, other types of infections, otitis media. Disorders of the blood and lymphatic system: often - leukopenia, unknown - thrombocytopenia. Immune system disorders: Infrequently - allergic reactions, including urticaria, unknown - hypersensitivity, including systemic reactions, such as fever, rashes, hepatitis, lymphadenopathy, eosinophilia, and others. Metabolic and nutritional disorders: often anorexia, increased appetite. Mental disorders: often - hostility, confusion, depression, anxiety, nervousness, impaired thinking, emotional lability, rarely - deterioration of mental state, unknown - hallucinations. Violations of the nervous system: very often - drowsiness, dizziness, ataxia, often - convulsions, hyperkinesia.dysarthria, amnesia, tremor, insomnia, headache, sensitivity disorder (eg, paresthesia, hypesthesia), impaired coordination, nystagmus, increased, weakened or absent reflexes, rarely - hypokinesia, rarely - loss of consciousness, unknown - other movement disorders (eg choreoathetosis, dyskinesia and dystonia). Violations of the organ of vision: often - visual impairment (such as, amblyopia, diplopia). Disturbances from an organ of hearing and labyrinth disturbances: often - vertigo, it is not known - tinnitus. Disturbances from the heart: infrequently - a sensation of heartbeat. Vascular disorders: often - symptoms of vasodilation or arterial hypertension. Disturbances of the respiratory system, organs of the chest and mediastinum: often - shortness of breath, bronchitis, pharyngitis, cough, rhinitis. Disorders of the gastrointestinal tract: often - constipation, diarrhea, dryness of the oral mucosa or pharynx, dyspepsia, flatulence, nausea, vomiting, abdominal pain, diseases of the teeth, gingivitis, unknown - pancreatitis. Disorders of the liver and biliary tract: unknown - hepatitis, jaundice. Violations of the skin and subcutaneous tissues: often - swelling of the face, purpura (most often it was described as bruising caused by physical trauma), skin rash, acne, itchy skin, unknown - Stevens-Johnson syndrome, angioedema, erythema multiforme, alopecia , drug skin rash, including eosinophilia and systemic reactions. Disorders of the musculoskeletal and connective tissues: often - myalgia, arthralgia, back pain, muscle twitching, unknown - rhabdomyolysis, myoclonus. Renal and urinary tract disorders: unknown - urinary incontinence, acute renal failure. Disorders of the genital organs and the mammary gland: often - impotence, unknown - an increase in the volume of the mammary glands, gynecomastia, sexual dysfunction (including changes in libido, ejaculation disorders and anorgasmia). General disorders and disorders at the injection site: very often - fatigue, fever, often - peripheral edema, gait disturbance, asthenia, pain of various localization, general malaise, flu-like syndrome, infrequently - generalized edema, unknown - withdrawal syndrome (the following undesirable reactions: anxiety, insomnia, nausea, pains of different localization and increased sweating), chest pain.There have been cases of sudden unexplained death, whose connection with treatment with gabapentin has not been established. Laboratory and instrumental data: often - decrease in white blood cell concentration, weight gain, infrequently - increase in alanine aminotransferase, aspartate aminotransferase and plasma bilirubin concentrations, hyperglycemia, rarely - hypoglycemia (mainly in patients with diabetes mellitus), unknown - hyponatremia, increase activity of creatine phosphokinase. Injuries, intoxications and complications of manipulation: often - injuries, fractures, abrasions associated with falls. There are reports of the development of acute pancreatitis during therapy with gabapentin. The causal relationship with gabapentin remains unclear. There are reports of cases of myopathy with an increase in the activity of creatine kinase in patients with end-stage renal failure on hemodialysis. Cases of respiratory tract infection, otitis media, bronchitis and seizures were noted only in clinical studies. In addition, cases of aggressive behavior and hyperkinesis in children have been reported in clinical studies.
Overdose
With a single dose of 49 g of gabapentin, the following symptoms were observed: dizziness, double vision, impaired speech, drowsiness, loss of consciousness, a state of lethargy and mild diarrhea, which completely disappeared during symptomatic therapy. It should be borne in mind that after taking high doses of gabapentin, its absorption in the intestine decreases. With an overdose of gabapentin, coma may develop, especially with simultaneous use of other drugs that suppress the central nervous system. Despite the fact that gabapentin can be eliminated during hemodialysis, experience shows that usually this need does not arise. Hemodialysis may be indicated in patients with severe renal insufficiency.
Interaction with other drugs
There are reports of spontaneous cases, as well as information from literary sources, respiratory depression and / or sedation symptoms associated with taking gabapentin and opioid analgesics are possible. In some of these cases, the authors associated these symptoms with the simultaneous use of gabapentin and opioids, especially in elderly patients.When using 600 mg of gabapentin 2 hours after taking morphine in the form of 60 mg prolonged-release capsules, an increase in the average AUC of gabapentin by 44% is observed compared to gabapentin monotherapy, which is associated with an increase in pain threshold (cold pressure test). The clinical significance of this change has not been established, and the pharmacokinetic characteristics of morphine did not change. Adverse reactions with co-administration of morphine and gabapentin did not differ from those of taking morphine together with placebo. The degree of interaction of these drugs in other doses is unknown. The interaction between gabapentin and phenobarbital, phenytoin, valproic acid and carbamazepine was not observed. The pharmacokinetics of gabapentin in the equilibrium state are the same in healthy people and patients receiving other anticonvulsants. Simultaneous use of gabapentin with oral contraceptives containing norethisterone and / or ethinyl estradiol is not accompanied by changes in the pharmacokinetics of both components. The simultaneous use of gabapentin with antacids containing aluminum and magnesium is accompanied by a decrease in the bioavailability of gabapentin by about 24%. Probenecid does not affect the renal excretion of gabapentin. A slight decrease (14%) in renal excretion of gabapentin with simultaneous administration of cimetidine is probably not of clinical significance. With simultaneous use of naproxen (250 mg) and gabapentin (125 mg), gabapentin absorption increased from 12% to 15%. Gabapentin does not affect the pharmacokinetic parameters of naproxen. The indicated doses of drugs are less than the minimum therapeutic. The simultaneous use of these drugs in large doses has not been studied.
special instructions
Antiepileptic drugs, including gabapentin, may increase the risk of suicidal thoughts or behavior, but the mechanism of their development is unknown. A meta-analysis of randomized, placebo-controlled antiepileptic studies showed a slight increase in the risk of suicidal thoughts and behavior. Therefore, patients receiving these drugs should be carefully monitored for the occurrence or worsening of depression, the appearance of suicidal thoughts or behavior, as well as for any changes in behavior. If signs of suicidal thoughts or behavior appear, patients or their caregivers should consult a doctor.Acute pancreatitis: in the case of developed acute pancreatitis with gabapentin intake, the possibility of drug withdrawal should be assessed. Convulsions (withdrawal syndrome): although the "withdrawal" syndrome, accompanied by the development of convulsions, is not observed with gabapentin treatment, an abrupt discontinuation of anticonvulsant therapy in patients with epilepsy can provoke the development of epileptic status. As with the use of other antiepileptic drugs, with the use of gabapentin, there may be an increase in the frequency of seizures or the appearance of another type of seizures. As with other anticonvulsants, attempts to cancel all concomitant antiepileptic drugs in order to begin gabapentin monotherapy in case of refractoriness to treatment in patients taking several anticonvulsants do not end in success. It is believed that gabapentin is not effective for primary generalized seizures, for example, absences, and may even intensify such seizures in some patients. In this regard, the use of gabapentin in patients with mixed seizures, including absansy, should be with caution. Elderly patients: systematic studies of patients aged 65 years and older, taking gabapentin, were not conducted. In a double-blind study of the use of gabapentin in neuropathic pain in patients aged 65 years and older, a higher incidence of drowsiness, peripheral edema, and asthenia was observed compared with patients younger than 65 years of age. With the exception of these results, the clinical examination of this group of patients showed that their side effect profile did not differ from the rest. Children: the effect of long-term therapy (more than 36 weeks) with gabapentin on learning ability, intelligence and child development has not been studied enough. It is necessary to assess the ratio of the possible risk and benefit in the appointment of long-term therapy. Abuse and dependence: in the database of post-registration observations there are reports of cases of drug abuse and dependence on it. As in the case of any drug that affects the central nervous system, doctors should carefully study the patient's history of drug abuse and monitor them in order to identify possible signs of gabapentin abuse (for example, unreasonable desire to get the drug, development of resistance to gabapentin therapy. Unreasonable dose increase ).