Pharmacodynamics Gabapentin 600 mg:
Gabapentin is similar in structure to the neurotransmitter gamma-aminobutyric acid (GABA). however, its mechanism of action differs from other drugs that interact with GABA receptors (valproic acid, barbiturates, benzodiazepines, GABA-transaminase inhibitors. inhibitors capture GABA agonists GABA and prodrugs of GABA). He does not have GABA-ergic properties and does not affect the seizure and metabolism of GABA. Preliminary studies have shown that gabapentin binds to the DL-b-subunit of voltage-dependent calcium channels and reduces the flow of calcium ions, which plays an important role in the development of neuropathic pain. Other mechanisms of action of gabapentin for neuropathic pain are to reduce the glutamate-dependent neuronal death, increased synthesis of GABA, inhibition of monoamine neurotransmitter release group. Gabapentin in clinically relevant concentrations does not bind to receptors that are sensitive to other drugs (drugs), or neurotransmitters. including receptors GAMKd. GAMKts. benzodiazepine, glutamate. glycine or N-methyl-c1-aspartate. In contrast to phenytoin and carbamazepine gabapentin does not interact with sodium channels in vitro. Gabapentin partially attenuated the effects of agonist glutamate receptors N-methyl-d-aspartate in some tests, in vitro, but only at a concentration of 100 micromoles, which is not achieved in vivo. Gabapentin reduces the release of several monoamine neyrotransmitgerov in vitro.
Pharmacokinetics Gabapentin 600 mg:
Gabapentin bioavailability is not proportional to dose. So. with increasing dose, it decreases. After oral administration, maximum concentration (Stach), gabapentin in plasma is reached after 2-3 h. The absolute bioavailability of gabapentin in capsules is about 60%. Food, including high-fat diet has no effect nafarmakokinetiku. The half-life (T) from the plasma does not depend on the dose and is an average of 5-7 hours Pharmacokinetics do not vary with repeated use, the equilibrium concentration in the plasma can be predicted on the basis of a single dose of the drug. Gabapentin is practically not bound to plasma proteins (
Indications Gabapentin 600 mg:
• Epilepsy: partial seizures with secondary generalization, and without her children and adults over 12 years (monotherapy): partial seizures with secondary generalization and without adults (extra HP)-resistant form of epilepsy in children older than 3 years (extra HP).
• neuropathic pain in adults (18 years and older).
Contraindications Gabapentin 600 mg:
Hypersensitivity to any component of the drug, the age of 12 years (because of the impossibility of accurate dosing).
Precautions
Renal failure (see “Dosage and administration”).
Pregnancy and lactation Gabapentin 600 mg
There are no data on the use of the drug in pregnant women, so gabapentin should be used during pregnancy only if the expected benefit to the mother justifies the potential risk to the fetus.
Gabapentin is excreted in breast milk, its effect on the lactating baby is unknown, so during treatment should abandon breastfeeding.
Dosage and administration Gabapentin 600 mg
Inside, swallowing a whole, irrespective of food intake and drinking plenty of fluid. If you want to reduce the dose of medication to cancel or replace it with alternative means, it should be done gradually over a minimum of one week.
Neuropathic pain in adults Gabapentin 600 mg
The initial daily dose is 900 mg. divided into three portions, if necessary, gradually increase the dose to the maximum – 3600 mg / day. Treatment can start with a dose of 900 mg / day (300 mg 3 times daily) or within the first 3 days the dose can be increased gradually to 900 mg in a \ weave as follows:
Day 1: 300 mg 1 time per day
2 – Day: 300 mg 2 times a day
3rd day: 300 mg 3 times daily
Partial Seizures Gabapentin 600 mg
Adults and dety of 12 years: Effective dose – from 900 to 3600 mg / day. Therapy can be started at a dose of 300 mg 3 times daily for the first time or increase gradually to 900 mg according to the scheme described above (see “Neuropathic pain in adults”). In a subsequent dose may be increased to a maximum of 3600 mg / day (divided into 3 equal doses). Maximum intervap between doses when taking the drug three times should not exceed 12 hours in order to avoid the resumption of seizures.
Dosing in renal failure .
Patients with renal insufficiency is recommended to decrease the dose of gabapentin according to the table:
| Creatinine clearance (ml / min) | Daily dose (mg / day) |
|
> 80 |
900-2400 |
|
50-79 |
600-1200 |
|
30-49 |
300-600 |
|
15-29 |
150 *- 300 |
|
150 * |
* Administered 300 mg every other day.
Recommendations for patients on hemodialysis
Patients on hemodialysis who had not previously received gabapentin. drug recommended in the saturating dose of 300-400 mg. and then apply it to 200-300mg every 4 hours of hemodialysis.
Side effects Gabapentin 600 mg:
Cardiovascular system: symptoms of vasodilation, or increased blood pressure, heart rate.
Digestive System: flatulence, anorexia. gingivitis, abdominal pain, constipation, dental disease (including changing the color of tooth enamel), diarrhea, dyspepsia, increased appetite, dry mouth or throat, nausea, vomiting, pancreatitis, increased activity of “liver” and called trance. hepatitis, jaundice.
Blood system, lymphatic system: purple (most often it is described as bruises that occurred during physical trauma), leukopenia, and thrombocytopenia.
Musculoskeletal system: arltralgiya. back pain, increased fragility of bones, joints.
Nervous system: dizziness: headache giperkineey: muscular dystonia and dyskinesia: choreoathetosis, weakening or absence of tendon reflexes: dysarthria: ataxia: niszagm, paresthesia, convulsions: confusion: fatigue, asthenia, amnesia, depression: thought disorder: the hostility: emotional lability;
Insomnia: anxiety, drowsiness, hallucinations tremor: tics: ill.
Respiratory system: rhinitis, pharyngitis, bronchitis, pneumonia, cough, shortness of breath, respiratory infection.
Skin and subcutaneous tissue: acne. peripheral edema, allergic reaction include itching, skin rash, erythema multiforme (including Stevens-Johnson syndrome).
Urogenital: urinary bullet, impotence, urinary incontinence, acute renal failure.
Special Senses: blurred vision, amblyopia. diplopia, tinnitus. otitis media.
Other: fever, viral infection, weight gain, glucose lability
blood plasma in diabetic patients, the pain of different localization, gynecomastia,
breast enlargement, generalized edema.
Overdose Gabapentin 600 mg:
Symptoms include dizziness, double vision, impaired speech, drowsiness, lethargy, diarrhea, and increased severity of other side effects. Treatment: gastric lavage, activated charcoal, symptomatic therapy. Patients with severe renal insufficiency, hemodialysis may be indicated.
Interactions with other drugs Gabapentin 600 mg:
Morphine: When coadministration of gabapentin and morphine when morphine is taken 2 hours before taking gabapentin, an increase in the average make a mistake under the pharmacokinetic curve “concentration – time» (AUG) of gabapentin by 44% compared to gabapentin monotherapy. that was associated with an increase in pain threshold (cold pressor test). The clinical significance of this change has not been established, the pharmacokinetic characteristics of morphine is not altered. Side “effects of morphine during coadministration with gabapentin did not differ from those when taking morphine with placebo.
Interactions between gabapentin and phenobarbital, phenytoin. valproic acid and carbamazepine were observed. Pharmacokinetics of gabapentin in the equilibrium state is identical in healthy persons and patients receiving other anticonvulsants. The simultaneous use of gabapentin with oral contraceptives containing norethisterone and / or ethinyl estradiol. not accompanied by changes in the pharmacokinetics of the two components.
The simultaneous use of gabapentin with antacids. containing aluminum and magnesium, is accompanied by a decrease in the bioavailability of gabapentin by about 20%. Gabapentin is recommended to take about 2 hours after taking an antacid. Probenecid does not affect the renal excretion of gabapentin.
A slight decrease in renal excretion of gabapentin at the same time taking cimetidine. probably has no clinical significance.
Cautions:
Although a withdrawal syndrome with the development of seizures in the treatment of gabapentin is not marked, however, abrupt discontinuation of therapy, antiepileptic drugs in patients with partial seizures may provoke the development of seizures (see Dosage and administration).
Gabapentin is not effective in the treatment of epilepsy-absans.
In patients who require joint treatment with morphine may need to increase the dose of gabapentin. It is necessary to ensure thorough monitoring of patients for the development of such a sign of oppression of the central nervous system (CNS) as drowsiness. In this case, the dose of gabapentin or morphine should be reduced appropriately (see “Interaction with other medicinal products”).
Laboratory studies
When adding gabapentin to other anticonvulsant drugs have been reported false-positive results in the determination of protein in the urine with test strips Ames N-Multistix SG . To determine the protein in the urine is recommended to use a specific method of sulfosalicylic acid precipitation.
Patients should avoid driving, as well as performance of work requiring speed performance of psychomotor reactions.
