Product Overview
【Drug Name】
Generic Name: Gabapentin Capsules
Brand Name: Patin
English Name: Gabapentin Capsules
Pinyin: Jiabapending Jiaonang
【Ingredients】
The main ingredient of this product is gabapentin, whose chemical name is 1-(aminomethyl)-cyclohexanoic acid.
【Appearance】
This product is a hard capsule containing off-white granules and powder.
【Indications】
1. Postherpetic neuralgia: Used for the treatment of postherpetic neuralgia in adults.
2. Epilepsy: Used as adjunctive therapy for partial seizures in adults and children over 12 years of age, with or without secondary generalized seizures. It can also be used as adjunctive therapy for partial seizures in children aged 3–12 years.
【Dosage and Administration】
1. Postherpetic neuralgia: On the first day, take 0.3g of gabapentin once, on the second day, take 0.6g, divided into two doses; on the third day, take 0.9g, divided into three doses. Subsequently, as needed to relieve pain, the dose can be gradually increased to 1.8g daily, divided into three doses. In international clinical studies, efficacy was comparable within a daily dose range of 1.8g to 3.6g, with no additional benefit observed at doses exceeding 1.8g per day.
2. Epilepsy: Gabapentin can be used in combination therapy with other antiepileptic drugs.
Gabapentin is administered orally, in divided doses (three times daily). The dosage should be gradually increased from an initial low dose to the effective dose. For patients 12 years and older: On the first day, administer 0.3g once daily; on the second day, administer 0.3g twice daily; on the third day, administer 0.3g three times daily, and maintain this dose thereafter. According to international research literature, the dosage of gabapentin can be increased to 1.8g daily, and some patients tolerate doses up to 2.4g daily. The safety of doses exceeding 2.4g daily is uncertain.
For pediatric patients aged 3–12 years: The initial dose should be 10–15 mg/kg/day, three times daily, reaching an effective dose in approximately three days. For patients aged 5 years and older, the effective dose of gabapentin is 25–35 mg/kg/day, three times daily. For pediatric patients aged 3–4 years, the effective dose is 40 mg/kg/day, three times daily. If necessary, the dose can be increased to 50 mg/kg/day. Long-term clinical studies have shown that the dose increase to 50 mg/kg/day is well tolerated. The interval between two doses should not exceed 12 hours. To reduce the occurrence of adverse reactions such as dizziness and drowsiness, the first dose can be taken at bedtime.
Monitoring of gabapentin blood concentration is not required during gabapentin treatment. Furthermore, since gabapentin has no significant pharmacokinetic interactions with other conventional antiepileptic drugs, combination therapy with this drug will not alter the plasma concentrations of these conventional antiepileptic drugs.
During treatment, discontinuation of gabapentin or introduction of a new treatment regimen should be gradual, with a minimum interval of one week.
【Adverse Reactions】
1. Postherpetic neuralgia: Primarily dizziness, drowsiness, and peripheral edema. Other adverse events occurring in a higher rate than 1% in foreign clinical trials and higher than in the placebo control group.
2. Seizures: The most common adverse events are drowsiness, fatigue, dizziness, headache, nausea, vomiting, weight gain, nervousness, insomnia, ataxia, nystagmus, paresthesia, and anorexia.
【Contraindications】
Gabapentin capsules are contraindicated in individuals with known hypersensitivity to any component of this drug and in patients with acute pancreatitis. Gabapentin capsules are ineffective for primary generalized seizures, such as absence seizures.
【Precautions】
Foreign studies report that withdrawal may induce seizures and status epilepticus. Antiepileptic drugs should not be abruptly discontinued as this may increase the frequency of seizures. In placebo-controlled studies, the incidence of status epilepticus was 0.6% (3/543) in the gabapentin treatment group and 0.5% (2/378) in the placebo group. Of the 2074 patients treated with gabapentin in all studies (including controlled and uncontrolled), 31 (1.5%) experienced status epilepticus. Fourteen of these patients had not experienced status epilepticus in previous treatments or while taking other medications. Due to insufficient patient history data, it cannot be concluded whether gabapentin treatment is associated with a higher or lower incidence of status epilepticus compared to those not treated with gabapentin. Potential carcinogenicity: Preclinical animal carcinogenicity studies found a higher incidence of pancreatic acinar adenocarcinoma in male rats; the clinical significance of this result is unclear. Premarket clinical studies of gabapentin are unclear regarding its potential to induce tumors in humans. The clinical study included 2085 patients on long-term gabapentin therapy. Within two years of discontinuing gabapentin, 10 patients developed new tumors (2 breast cancers, 3 brain cancers, 2 lung cancers, 1 adrenal cancer, 1 non-Hodgkin's lymphoma, and 1 endometrial cancer), and 11 patients experienced tumor progression (9 brain cancers, 1 breast cancer, and 1 prostate cancer). Because there was no background data on tumor incidence and recurrence rates in a similar population not treated with gabapentin, it is impossible to know whether the treatment in this study affected the incidence. Sudden and unexplained deaths: During the premarketing studies of gabapentin, 8 out of 2203 patients (2103 of whom were on long-term therapy) experienced sudden and unexplained deaths. Some of these deaths could be explained as being caused by seizures, such as undetected seizures at night. The incidence of this event was 0.0038 person-years. Although this rate exceeds that of healthy individuals of the same age and sex, it falls within the range of sudden death rates in epilepsy patients not taking gabapentin (from 0.0005 in the general population to 0.003 in clinical trial populations similar to this trial, or 0.0005 to 0.005 in refractory patients). Therefore, the reliability of the results depends on the comparability of the populations receiving gabapentin treatment and the accuracy of the statistics. Special precautions: In clinical controlled studies, 16% of patients experienced potentially clinically significant fluctuations in blood glucose (<3.3 mmol/L or ≥7.8 mmol/L, normal range 3.5–5.5 mmol/L). Therefore, diabetic patients should monitor their blood glucose frequently and adjust their hypoglycemic drug dosage as necessary. Patients with renal insufficiency must reduce the dosage of this product (see Dosage and Administration). There have been reports of hemorrhagic pancreatitis occurring with this product. Therefore, if clinical symptoms of pancreatitis (persistent abdominal pain, nausea, recurrent vomiting) occur, this product should be discontinued immediately, and a comprehensive physical examination, clinical and laboratory tests should be performed to diagnose pancreatitis as early as possible. There is insufficient experience with the use of gabapentin in patients with chronic pancreatitis; its use should be determined by a physician. Patients receiving concurrent morphine treatment may experience elevated gabapentin blood concentrations. Patients should be carefully monitored for central nervous system depression such as drowsiness, and the dosage of gabapentin or morphine should be appropriately reduced (see Drug Interactions). Effects on Driving and Machine Operation: This product acts on the central nervous system and can cause sedation, dizziness, or similar symptoms. Therefore, even when taken at the prescribed dose, this product can reduce reaction time and impair the ability to drive, operate complex machinery, and work in exposed environments, especially at the beginning of treatment, when increasing the dosage, changing medications, or when consuming alcohol.
【Special Populations】
Precautions in Children: Not yet clear.
Precautions during Pregnancy and Lactation: There is currently no experience with the use of this product in pregnant women. This product should only be used after a thorough assessment of the benefits/risks. This product is secreted in breast milk. Because the possibility of serious adverse events in infants cannot be ruled out, breastfeeding women should discontinue breastfeeding or use this product if it is necessary to use it (considering the necessity of antiepileptic treatment for the mother).
Precautions for the elderly: No systematic studies have been conducted in individuals over 65 years of age. However, clinical observations indicate that adverse events in this age group are not significantly different from those in younger individuals.
【Drug Interactions】
Gabapentin is minimally metabolized and does not interfere with the metabolism of other commonly used antiepileptic drugs. The drug interaction data described in this section are from studies in relevant healthy adults and patients with epilepsy.
【Pharmacological Action】
The mechanism of gabapentin's anticonvulsant effect is not fully understood, but animal studies suggest that, similar to other marketed anticonvulsants, gabapentin can suppress seizures. Maximum electroshock tests in mice and rats, benzothiazole seizure tests, and other animal studies (such as hereditary epilepsy models) suggest that gabapentin has antiepileptic activity, but the relevance of these epilepsy models to humans is unclear. Gabapentin is structurally associated with the neurotransmitter GABA but does not interact with GABA receptors. It is neither metabolized into GABA or a GABA agonist, nor is it an inhibitor of GABA uptake or degradation. Radioligand binding assays have shown that gabapentin at concentrations up to 100 μM has no affinity for many common receptor sites, including benzodiazepine receptors, glutamate receptors, NMDA receptors, quisqualate receptors, hainanoxalate receptors, strychnine-insensitive or -sensitive glycine receptors, α1, α2, or β receptors, adenosine A1 or A2 receptors, M or N receptors, dopamine D1 or D2 receptors, H1 receptors, serotonin S1 or S2 receptors, opioid μ, δ, or k receptors, voltage-sensitive calcium channel sites labeled with nifedipine or diltiazem, and voltage-sensitive sodium channel sites labeled with rotatoxin A 20-α-benzoate. Because several commonly used tests evaluating the effects of drugs on NMDA receptors have yielded conflicting results, there is currently no unified understanding regarding the effects of gabapentin on NMDA receptors. In vitro studies show that gabapentin's binding sites in the rat brain are distributed in the neocortex and hippocampus. Its high-affinity binding protein has been confirmed as an auxiliary subunit of voltage-activated calcium channels, but its related functions remain unclear.
【Storage】
Store in a tightly closed container, avoiding high temperatures.
【Specifications】
0.3g
【Packaging Specifications】
Aluminum-plastic packaging.
【Shelf Life】
24 months
【Approval Number】
National Drug Approval Number H20050271
【Manufacturer】
Company Name: Jiangsu Hengrui Medicine Co., Ltd.
