Gabanext

Uses

Gabanext is used for the management of neuropathic pain associated with diabetic peripheral neuropathy and management of post-herpetic neuralgia. It is also used for the adjunctive therapy for adult patients with partial onset seizures. It can be used for the management of fibromyalgia and neuropathic pain associated with spinal cord injury.

Gabanext is also used to associated treatment for these conditions: Diabetic Peripheral Neuropathic Pain (DPN), Epilepsies, Fibromyalgia, Generalized Anxiety Disorder (GAD), Neuropathic Pain, Partial-Onset Seizures, Peripheral Neuropathic Pain, Peripheral neuropathy, Postherpetic Neuralgia

How Gabanext works

Although the mechanism of action has not been fully elucidated, studies involving structurally related drugs suggest that presynaptic binding of pregabalin to voltage-gated calcium channels is key to the antiseizure and antinociceptive effects observed in animal models.

By binding presynaptically to the alpha2-delta subunit of voltage-gated calcium channels in the central nervous system, pregabalin modulates the release of several excitatory neurotransmitters including glutamate, substance-P, norepinephrine, and calcitonin gene related peptide. In addition, pregabalin prevents the alpha2-delta subunit from being trafficked from the dorsal root ganglia to the spinal dorsal horn, which may also contribute to the mechanism of action.

Although pregabalin is a structural derivative of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA), it does not bind directly to GABA or benzodiazepine receptors.

Dosage

Gabanext dosage

Neuropathic pain associated with diabetic peripheral neuropathy: The maximum recommended dose of Gabanext is 100 mg three times a day (300 mg/day) in patients with creatinine clearance of at least 60 mL/min. Dosing should begin at 50 mg three times a day (150 mg/day) and may be increased to 300 mg/day within 1 week based on efficacy and tolerability.

Post-herpetic neuralgia: The recommended dose of Gabanext is 75 to 150 mg two times a day, or 50 to 100 mg three times a day (150 to 300 mg/day) in patients with creatinine clearance of at least 60 mL/min. Dosing should begin at 75 mg two times a day, or 50 mg three times a day (150 mg/day) and may be increased to 300 mg/day within 1 week based on efficacy and tolerability.

Adjunctive therapy for adult patients with partial onset seizures: Gabanext at doses of 150 to 600 mg/day has been shown to be effective as adjunctive therapy in the treatment of partial onset seizures in adults. The total daily doseshould be divided and given either two or three times daily. In general, it is recommended that patients be started on a total daily dose no greater than 150 mg/day (75 mg two times a day, or 50 mg three times a day). Based on individual patient response and tolerability, the dose may be increased to a maximum dose of 600 mg/day.

Management of Fibromyalgia: The recommended dose of Gabanext for fibromyalgia is 300 to 450 mg/day. Dosing should begin at 75 mg two times a day (150 mg/day) and may be increased to 150 mg two times a day (300 mg/day) within 1 week based on efficacy and tolerability. Patients who do not experience sufficient benefit with 300 mg/day may be further increased to 225 mg two times a day (450 mg/day).

Neuropathic pain associated with spinal cord injury: The recommended dose range is 150 to 600 mg/day. The recommended starting dose is 75 mg two times a day (150 mg/day). The dose may be increased to 150 mg two times a day (300 mg/day) within 1 week based on efficacy and tolerability.

.Patients who do not experience sufficient pain relief after treatment with 300 mg/day and who tolerate pregabalin may be treated with up to 300 mg two times a day. Neurolin® capsules can be taken without regards to meals.

Side Effects

The most common side effects include dizziness, somnolence, dry mouth, edema, blurred vision, weight gain, and abnormal thinking.

Toxicity

In a systematic review that included 38 randomized controlled trials, there were 20 identified adverse effects that were significantly associated with pregabalin, most of which involve the central nervous system and cognition. The identified adverse effects include vertigo, dizziness, balance disorder, incoordination, ataxia, blurred vision, diplopia, amblyopia, somnolence, confusional state, tremor, disturbance in attention, abnormal thinking, asthenia, fatigue, euphoria, edema, peripheral edema, dry mouth, and constipation .

The most common symptoms of pregabalin toxicity (dose range includes 800 mg/day and single doses up to 11,500 mg) include somnolence, confusion, restlessness, agitation, depression, affective disorder and seizures.

Since there is no antidote for pregabalin overdose, patients should receive general supportive care. If appropriate, gastric lavage or emesis may help eliminate unabsorbed pregabalin (healthcare providers should take standard precautions to maintain the airway).

Gabanext pharmacokinetic properties suggest that extra-corporeal elimination methods including haemodialysis, may be useful in situations of severe toxicity. However, there are cases where patients have presented with very high serum levels of pregabalin and have been successfully managed with supportive care alone.

Precaution

Discontinuation of Gabanext without tapering may produce insomnia, nausea, headache and diarrhea. So it should be tapered gradually over a minimum of 1 week rather than discontinued abruptly. Creatinine kinase may be elevated if treated with Gabanext. It should be discontinued rapidly if myopathy is diagnosed or suspected or if creatinine kinase is elevated markedly.

Food Interaction

• Avoid alcohol. Alcohol may increase CNS effects.
• Take with or without food. Food alters drug absorption, but not to a clinically significant extent.

[Moderate] GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of CNS-active agents.

Use in combination may result in additive central nervous system depression and
MANAGEMENT: Patients receiving CNS-active agents should be warned of this interaction and advised to avoid or limit consumption of alcohol.

Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

Gabanext Drug Interaction

Major: acetaminophen / hydrocodoneModerate: diphenhydramine, duloxetine, alprazolam, cetirizineUnknown: aspirin, aspirin, celecoxib, apixaban, omega-3 polyunsaturated fatty acids, metoprolol, metoprolol, acetaminophen, budesonide / formoterol, levothyroxine, acetaminophen, cyanocobalamin, ascorbic acid, ergocalciferol, cholecalciferol

Gabanext Disease Interaction

Major: drug dependenceModerate: suicidal tendency, angioedema, creatine kinase elevations, peripheral edema, PR interval prolongation

Volume of Distribution

After oral administration of pregabalin, the reported apparent volume of distribution is roughly 0.5 L/kg.

Although pregabalin is not very lipophilic, it is able to cross the blood brain barrier(BBB). System L transporters facilitate the transport of large amino acids across the BBB and it has been confirmed that pregabalin is a substrate. This information suggests that system L transporters are responsible for pregabalin uptake into the BBB.

In rat models, pregabalin has been shown to cross the placenta.

Elimination Route

After oral dosing administered in the fasted state, pregabalin absorption is rapid, and extensive. Gabanext oral bioavailability is reported to be ≥90% regardless of the dose. Cmax is attained within 1.5 hours after single or multiple doses, and steady state is attained within 24-48 hours with repeated administration. Both Cmax and AUC appear to be dose proportional.

Food decreases the rate of pregabalin absorption and as a result, lowers the Cmax by an estimated 25-30% and increases the Tmax to approximately 3 hours. However, the effect of food does not appear to impact the total absorption of pregabalin in a way that is clinically relevant. As a result, pregabalin can be administered with or without food.

Half Life

The elimination half life of pregabalin is 6.3 hours.

Clearance

In young healthy subjects the mean renal clearance is estimated to be 67.0 to 80.9 mL mL/min. Given pregabalin's lack of plasma protein binding, this clearance rate suggests that renal tubular reabsorption is involved.

Elimination Route

Gabanext is almost exclusively eliminated in the urine.

Further, based on preclinical studies, pregabalin does not appear to undergo racemization to the R enantiomer in the body.

Pregnancy & Breastfeeding use

Pregnancy category C. So it should only used if potential benefit justifies the potential risks to the fetus.

Nursing mother: It is not known if pregabalin is excreted in human milk; it is, however, present in the milk of rats. So it should be used in nursing mother only if there is a clear benefit over the risk.

Contraindication

Gabanext is contraindicated in patients with known hypersensitivity to Gabanext or any of its components.

Special Warning

Use in children & adolescents: The safety and effectiveness of Gabanext have not been established in patients below the age of 18 years.

Use in elderly (Over 65 years of age): No dosage adjustment is necessary in elderly patients. Overdose: In overdoses up to 15 g, no unexpected adverse effects were reported.

Paediatric use: The safety and efficacy of pregabalin in paediatric patients have not been established.

Storage Condition

Store at a cool & dry place, protected from light and moisture. Keep out of reach of the children.

Innovators Monograph

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