|Labeler Name||Parke-Davis Div of Pfizer Inc|
|Dosage & Substance||tablet, film coated gabapentin|
|Date First Marketed||October 09, 1998|
NEURONTIN® is indicated for:
- Management of postherpetic neuralgia in adults
- Adjunctive therapy in the treatment of partial onset seizures, with and without secondary generalization, in adults and pediatric patients 3 years and older with epilepsy
NEURONTIN is contraindicated in patients who have demonstrated hypersensitivity to the drug or its ingredients.
The following serious adverse reactions are discussed in greater detail in other sections:
- Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)/Multiorgan Hypersensitivity
- Anaphylaxis and Angioedema
- Somnolence/Sedation and Dizziness
- Withdrawal Precipitated Seizure, Status Epilepticus
- Suicidal Behavior and Ideation
- Neuropsychiatric Adverse Reactions (Pediatric Patients 3–12 Years of Age)
- Sudden and Unexplained Death in Patients with Epilepsy [see Warnings and Precautions (5.9)]
6.1 Clinical Trials Experience
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
The most common adverse reactions associated with the use of NEURONTIN in adults, not seen at an equivalent frequency among placebo-treated patients, were dizziness, somnolence, and peripheral edema.
In the 2 controlled trials in postherpetic neuralgia, 16% of the 336 patients who received NEURONTIN and 9% of the 227 patients who received placebo discontinued treatment because of an adverse reaction. The adverse reactions that most frequently led to withdrawal in NEURONTIN-treated patients were dizziness, somnolence, and nausea.
Table 3 lists adverse reactions that occurred in at least 1% of NEURONTIN-treated patients with postherpetic neuralgia participating in placebo-controlled trials and that were numerically more frequent in the NEURONTIN group than in the placebo group.
|Body as a Whole|
|Metabolic and Nutritional Disorders|
Other reactions in more than 1% of patients but equally or more frequent in the placebo group included pain, tremor, neuralgia, back pain, dyspepsia, dyspnea, and flu syndrome.
There were no clinically important differences between men and women in the types and incidence of adverse reactions. Because there were few patients whose race was reported as other than white, there are insufficient data to support a statement regarding the distribution of adverse reactions by race.
Epilepsy with Partial Onset Seizures (Adjunctive Therapy)
The most common adverse reactions with NEURONTIN in combination with other antiepileptic drugs in patients >12 years of age, not seen at an equivalent frequency among placebo-treated patients, were somnolence, dizziness, ataxia, fatigue, and nystagmus.
The most common adverse reactions with NEURONTIN in combination with other antiepileptic drugs in pediatric patients 3 to 12 years of age, not seen at an equal frequency among placebo-treated patients, were viral infection, fever, nausea and/or vomiting, somnolence, and hostility.
Approximately 7% of the 2074 patients >12 years of age and approximately 7% of the 449 pediatric patients 3 to 12 years of age who received NEURONTIN in premarketing clinical trials discontinued treatment because of an adverse reaction. The adverse reactions most commonly associated with withdrawal in patients >12 years of age were somnolence (1.2%), ataxia (0.8%), fatigue (0.6%), nausea and/or vomiting (0.6%), and dizziness (0.6%). The adverse reactions most commonly associated with withdrawal in pediatric patients were emotional lability (1.6%), hostility (1.3%), and hyperkinesia (1.1%).
Table 4 lists adverse reactions that occurred in at least 1% of NEURONTIN-treated patients >12 years of age with epilepsy participating in placebo-controlled trials and were numerically more common in the NEURONTIN group. In these studies, either NEURONTIN or placebo was added to the patient’s current antiepileptic drug therapy.
|Body As A Whole|
|Dry Mouth or Throat||2||1|
|Skin and Appendages|
Among the adverse reactions occurring at an incidence of at least 10% in NEURONTIN-treated patients, somnolence and ataxia appeared to exhibit a positive dose-response relationship.
The overall incidence of adverse reactions and the types of adverse reactions seen were similar among men and women treated with NEURONTIN. The incidence of adverse reactions increased slightly with increasing age in patients treated with either NEURONTIN or placebo. Because only 3% of patients (28/921) in placebo-controlled studies were identified as nonwhite (black or other), there are insufficient data to support a statement regarding the distribution of adverse reactions by race.
Table 5 lists adverse reactions that occurred in at least 2% of NEURONTIN-treated patients, age 3 to 12 years of age with epilepsy participating in placebo-controlled trials, and which were numerically more common in the NEURONTIN group.
|Body As A Whole|
|Nausea and/or Vomiting||8||7|
Other reactions in more than 2% of pediatric patients 3 to 12 years of age but equally or more frequent in the placebo group included: pharyngitis, upper respiratory infection, headache, rhinitis, convulsions, diarrhea, anorexia, coughing, and otitis media.
6.2 Postmarketing Experience
The following adverse reactions have been identified during postmarketing use of NEURONTIN. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Hepatobiliary disorders: jaundice
Investigations: elevated creatine kinase, elevated liver function tests
Metabolism and nutrition disorders: hyponatremia
Musculoskeletal and connective tissue disorder: rhabdomyolysis
Nervous system disorders: movement disorder
Psychiatric disorders: agitation
Reproductive system and breast disorders: breast enlargement, changes in libido, ejaculation disorders and anorgasmia
Skin and subcutaneous tissue disorders: angioedema, erythema multiforme, Stevens-Johnson syndrome.
Adverse reactions following the abrupt discontinuation of gabapentin have also been reported. The most frequently reported reactions were anxiety, insomnia, nausea, pain, and sweating.
5.1 Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)/Multiorgan Hypersensitivity
Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), also known as multiorgan hypersensitivity, has occurred with NEURONTIN. Some of these reactions have been fatal or life-threatening. DRESS typically, although not exclusively, presents with fever, rash, and/or lymphadenopathy, in association with other organ system involvement, such as hepatitis, nephritis, hematological abnormalities, myocarditis, or myositis sometimes resembling an acute viral infection. Eosinophilia is often present. This disorder is variable in its expression, and other organ systems not noted here may be involved.
It is important to note that early manifestations of hypersensitivity, such as fever or lymphadenopathy, may be present even though rash is not evident. If such signs or symptoms are present, the patient should be evaluated immediately. NEURONTIN should be discontinued if an alternative etiology for the signs or symptoms cannot be established.
5.2 Anaphylaxis and Angioedema
NEURONTIN can cause anaphylaxis and angioedema after the first dose or at any time during treatment. Signs and symptoms in reported cases have included difficulty breathing, swelling of the lips, throat, and tongue, and hypotension requiring emergency treatment. Patients should be instructed to discontinue NEURONTIN and seek immediate medical care should they experience signs or symptoms of anaphylaxis or angioedema.
5.3 Effects on Driving and Operating Heavy Machinery
Patients taking NEURONTIN should not drive until they have gained sufficient experience to assess whether NEURONTIN impairs their ability to drive. Driving performance studies conducted with a prodrug of gabapentin (gabapentin enacarbil tablet, extended release) indicate that gabapentin may cause significant driving impairment. Prescribers and patients should be aware that patients’ ability to assess their own driving competence, as well as their ability to assess the degree of somnolence caused by NEURONTIN, can be imperfect. The duration of driving impairment after starting therapy with NEURONTIN is unknown. Whether the impairment is related to somnolence or other effects of NEURONTIN is unknown.
Moreover, because NEURONTIN causes somnolence and dizziness, patients should be advised not to operate complex machinery until they have gained sufficient experience on NEURONTIN to assess whether NEURONTIN impairs their ability to perform such tasks.
5.4 Somnolence/Sedation and Dizziness
During the controlled epilepsy trials in patients older than 12 years of age receiving doses of NEURONTIN up to 1800 mg daily, somnolence, dizziness, and ataxia were reported at a greater rate in patients receiving NEURONTIN compared to placebo: i.e., 19% in drug versus 9% in placebo for somnolence, 17% in drug versus 7% in placebo for dizziness, and 13% in drug versus 6% in placebo for ataxia. In these trials somnolence, ataxia and fatigue were common adverse reactions leading to discontinuation of NEURONTIN in patients older than 12 years of age, with 1.2%, 0.8% and 0.6% discontinuing for these events, respectively.
During the controlled trials in patients with post-herpetic neuralgia, somnolence and dizziness were reported at a greater rate compared to placebo in patients receiving NEURONTIN, in dosages up to 3600 mg per day: i.e., 21% in NEURONTIN-treated patients versus 5% in placebo-treated patients for somnolence and 28% in NEURONTIN-treated patients versus 8% in placebo-treated patients for dizziness. Dizziness and somnolence were among the most common adverse reactions leading to discontinuation of NEURONTIN.
Patients should be carefully observed for signs of central nervous system (CNS) depression, such as somnolence and sedation, when NEURONTIN is used with other drugs with sedative properties because of potential synergy. In addition, patients who require concomitant treatment with morphine may experience increases in gabapentin concentrations and may require dose adjustment [see Drug Interactions (7.2)].
5.5 Withdrawal Precipitated Seizure, Status Epilepticus
Antiepileptic drugs should not be abruptly discontinued because of the possibility of increasing seizure frequency.
In the placebo-controlled epilepsy studies in patients >12 years of age, the incidence of status epilepticus in patients receiving NEURONTIN was 0.6% (3 of 543) vs. 0.5% in patients receiving placebo (2 of 378). Among the 2074 patients >12 years of age treated with NEURONTIN across all epilepsy studies (controlled and uncontrolled), 31 (1.5%) had status epilepticus. Of these, 14 patients had no prior history of status epilepticus either before treatment or while on other medications. Because adequate historical data are not available, it is impossible to say whether or not treatment with NEURONTIN is associated with a higher or lower rate of status epilepticus than would be expected to occur in a similar population not treated with NEURONTIN.
5.6 Suicidal Behavior and Ideation
Antiepileptic drugs (AEDs), including NEURONTIN, increase the risk of suicidal thoughts or behavior in patients taking these drugs for any indication. Patients treated with any AED for any indication should be monitored for the emergence or worsening of depression, suicidal thoughts or behavior, and/or any unusual changes in mood or behavior.
Pooled analyses of 199 placebo-controlled clinical trials (mono- and adjunctive therapy) of 11 different AEDs showed that patients randomized to one of the AEDs had approximately twice the risk (adjusted Relative Risk 1.8, 95% CI:1.2, 2.7) of suicidal thinking or behavior compared to patients randomized to placebo. In these trials, which had a median treatment duration of 12 weeks, the estimated incidence rate of suicidal behavior or ideation among 27,863 AED-treated patients was 0.43%, compared to 0.24% among 16,029 placebo-treated patients, representing an increase of approximately one case of suicidal thinking or behavior for every 530 patients treated. There were four suicides in drug-treated patients in the trials and none in placebo-treated patients, but the number is too small to allow any conclusion about drug effect on suicide.
The increased risk of suicidal thoughts or behavior with AEDs was observed as early as one week after starting drug treatment with AEDs and persisted for the duration of treatment assessed. Because most trials included in the analysis did not extend beyond 24 weeks, the risk of suicidal thoughts or behavior beyond 24 weeks could not be assessed.
The risk of suicidal thoughts or behavior was generally consistent among drugs in the data analyzed. The finding of increased risk with AEDs of varying mechanisms of action and across a range of indications suggests that the risk applies to all AEDs used for any indication. The risk did not vary substantially by age (5–100 years) in the clinical trials analyzed. Table 2 shows absolute and relative risk by indication for all evaluated AEDs.
|Indication||Placebo Patients with Events Per 1000 Patients||Drug Patients with Events Per 1000 Patients||Relative Risk: Incidence of Events in Drug Patients/Incidence in Placebo Patients||Risk Difference: Additional Drug Patients with Events Per 1000 Patients|
The relative risk for suicidal thoughts or behavior was higher in clinical trials for epilepsy than in clinical trials for psychiatric or other conditions, but the absolute risk differences were similar for the epilepsy and psychiatric indications.
Anyone considering prescribing NEURONTIN or any other AED must balance the risk of suicidal thoughts or behavior with the risk of untreated illness. Epilepsy and many other illnesses for which AEDs are prescribed are themselves associated with morbidity and mortality and an increased risk of suicidal thoughts and behavior. Should suicidal thoughts and behavior emerge during treatment, the prescriber needs to consider whether the emergence of these symptoms in any given patient may be related to the illness being treated.
Patients, their caregivers, and families should be informed that AEDs increase the risk of suicidal thoughts and behavior and should be advised of the need to be alert for the emergence or worsening of the signs and symptoms of depression, any unusual changes in mood or behavior, or the emergence of suicidal thoughts, behavior, or thoughts about self-harm. Behaviors of concern should be reported immediately to healthcare providers.
5.7 Neuropsychiatric Adverse Reactions (Pediatric Patients 3–12 Years of Age)
Gabapentin use in pediatric patients with epilepsy 3–12 years of age is associated with the occurrence of central nervous system related adverse reactions. The most significant of these can be classified into the following categories: 1) emotional lability (primarily behavioral problems), 2) hostility, including aggressive behaviors, 3) thought disorder, including concentration problems and change in school performance, and 4) hyperkinesia (primarily restlessness and hyperactivity). Among the gabapentin-treated patients, most of the reactions were mild to moderate in intensity.
In controlled clinical epilepsy trials in pediatric patients 3–12 years of age, the incidence of these adverse reactions was: emotional lability 6% (gabapentin-treated patients) vs. 1.3% (placebo-treated patients); hostility 5.2% vs. 1.3%; hyperkinesia 4.7% vs. 2.9%; and thought disorder 1.7% vs. 0%. One of these reactions, a report of hostility, was considered serious. Discontinuation of gabapentin treatment occurred in 1.3% of patients reporting emotional lability and hyperkinesia and 0.9% of gabapentin-treated patients reporting hostility and thought disorder. One placebo-treated patient (0.4%) withdrew due to emotional lability.
5.8 Tumorigenic Potential
In an oral carcinogenicity study, gabapentin increased the incidence of pancreatic acinar cell tumors in rats. The clinical significance of this finding is unknown. Clinical experience during gabapentin’s premarketing development provides no direct means to assess its potential for inducing tumors in humans.
In clinical studies in adjunctive therapy in epilepsy comprising 2085 patient-years of exposure in patients >12 years of age, new tumors were reported in 10 patients (2 breast, 3 brain, 2 lung, 1 adrenal, 1 non-Hodgkin’s lymphoma, 1 endometrial carcinoma), and preexisting tumors worsened in 11 patients (9 brain, 1 breast, 1 prostate) during or up to 2 years following discontinuation of NEURONTIN. Without knowledge of the background incidence and recurrence in a similar population not treated with NEURONTIN, it is impossible to know whether the incidence seen in this cohort is or is not affected by treatment.
5.9 Sudden and Unexplained Death in Patients with Epilepsy
During the course of premarketing development of NEURONTIN, 8 sudden and unexplained deaths were recorded among a cohort of 2203 epilepsy patients treated (2103 patient-years of exposure) with NEURONTIN.
Some of these could represent seizure-related deaths in which the seizure was not observed, e.g., at night. This represents an incidence of 0.0038 deaths per patient-year. Although this rate exceeds that expected in a healthy population matched for age and sex, it is within the range of estimates for the incidence of sudden unexplained deaths in patients with epilepsy not receiving NEURONTIN (ranging from 0.0005 for the general population of epileptics to 0.003 for a clinical trial population similar to that in the NEURONTIN program, to 0.005 for patients with refractory epilepsy). Consequently, whether these figures are reassuring or raise further concern depends on comparability of the populations reported upon to the NEURONTIN cohort and the accuracy of the estimates provided.
NEURONTIN (Neu rŏn’ tĭn)
Capsules, Tablets, and Oral Solution
Read the Medication Guide before you start taking NEURONTIN and each time you get a refill. There may be new information. This information does not take the place of talking to your healthcare provider about your medical condition or treatment.
What is the most important information I should know about NEURONTIN?
Do not stop taking NEURONTIN without first talking to your healthcare provider.
Stopping NEURONTIN suddenly can cause serious problems.
NEURONTIN can cause serious side effects including:
- Suicidal Thoughts. Like other antiepileptic drugs, NEURONTIN may cause suicidal thoughts or actions in a very small number of people, about 1 in 500.
Call a healthcare provider right away if you have any of these symptoms, especially if they are new, worse, or worry you:
- thoughts about suicide or dying
- attempts to commit suicide
- new or worse depression
- new or worse anxiety
- feeling agitated or restless
- panic attacks
- trouble sleeping (insomnia)
- new or worse irritability
- acting aggressive, being angry, or violent
- acting on dangerous impulses
- an extreme increase in activity and talking (mania)
- other unusual changes in behavior or mood
How can I watch for early symptoms of suicidal thoughts and actions?
- Pay attention to any changes, especially sudden changes, in mood, behaviors, thoughts, or feelings.
- Keep all follow-up visits with your healthcare provider as scheduled.
Call your healthcare provider between visits as needed, especially if you are worried about symptoms.
Do not stop taking NEURONTIN without first talking to a healthcare provider.
- Stopping NEURONTIN suddenly can cause serious problems. Stopping a seizure medicine suddenly in a patient who has epilepsy can cause seizures that will not stop (status epilepticus).
- Suicidal thoughts or actions can be caused by things other than medicines. If you have suicidal thoughts or actions, your healthcare provider may check for other causes.
- Changes in behavior and thinking – Using NEURONTIN in children 3 to 12 years of age can cause emotional changes, aggressive behavior, problems with concentration, restlessness, changes in school performance, and hyperactivity.
- NEURONTIN may cause serious or life-threatening allergic reactions that may affect your skin or other parts of your body such as your liver or blood cells. This may cause you to be hospitalized or to stop NEURONTIN. You may or may not have a rash with an allergic reaction caused by NEURONTIN. Call a healthcare provider right away if you have any of the following symptoms:
- skin rash
- difficulty breathing
- swollen glands that do not go away
- swelling of your face, lips, throat, or tongue
- yellowing of your skin or of the whites of the eyes
- unusual bruising or bleeding
- severe fatigue or weakness
- unexpected muscle pain
- frequent infections
These symptoms may be the first signs of a serious reaction. A healthcare provider should examine you to decide if you should continue taking NEURONTIN.
What is NEURONTIN?
NEURONTIN is a prescription medicine used to treat:
- Pain from damaged nerves (postherpetic pain) that follows healing of shingles (a painful rash that comes after a herpes zoster infection) in adults.
- Partial seizures when taken together with other medicines in adults and children 3 years of age and older with seizures.
Who should not take NEURONTIN?
Do not take NEURONTIN if you are allergic to gabapentin or any of the other ingredients in NEURONTIN. See the end of this Medication Guide for a complete list of ingredients in NEURONTIN.
What should I tell my healthcare provider before taking NEURONTIN?
Before taking NEURONTIN, tell your healthcare provider if you:
- have or have had kidney problems or are on hemodialysis
- have or have had depression, mood problems, or suicidal thoughts or behavior
- have diabetes
- are pregnant or plan to become pregnant. It is not known if NEURONTIN can harm your unborn baby. Tell your healthcare provider right away if you become pregnant while taking NEURONTIN. You and your healthcare provider will decide if you should take NEURONTIN while you are pregnant.
- If you become pregnant while taking NEURONTIN, talk to your healthcare provider about registering with the North American Antiepileptic Drug (NAAED) Pregnancy Registry. The purpose of this registry is to collect information about the safety of antiepileptic drugs during pregnancy. You can enroll in this registry by calling 1-888-233-2334.
- are breast-feeding or plan to breast-feed. NEURONTIN can pass into breast milk. You and your healthcare provider should decide how you will feed your baby while you take NEURONTIN.
Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.
Taking NEURONTIN with certain other medicines can cause side effects or affect how well they work. Do not start or stop other medicines without talking to your healthcare provider.
Know the medicines you take. Keep a list of them and show it to your healthcare provider and pharmacist when you get a new medicine.
How should I take NEURONTIN?
- Take NEURONTIN exactly as prescribed. Your healthcare provider will tell you how much NEURONTIN to take.
- Do not change your dose of NEURONTIN without talking to your healthcare provider.
- If you take NEURONTIN tablets and break a tablet in half, the unused half of the tablet should be taken at your next scheduled dose. Half tablets not used within 28 days of breaking should be thrown away.
- Take NEURONTIN capsules with water.
- NEURONTIN tablets can be taken with or without food. If you take an antacid containing aluminum and magnesium, such as Maalox®, Mylanta®, Gelusil®, Gaviscon®, or Di-Gel®, you should wait at least 2 hours before taking your next dose of NEURONTIN.
If you take too much NEURONTIN, call your healthcare provider or your local Poison Control Center right away at 1-800-222-1222.
What should I avoid while taking NEURONTIN?
- Do not drink alcohol or take other medicines that make you sleepy or dizzy while taking NEURONTIN without first talking with your healthcare provider. Taking NEURONTIN with alcohol or drugs that cause sleepiness or dizziness may make your sleepiness or dizziness worse.
- Do not drive, operate heavy machinery, or do other dangerous activities until you know how NEURONTIN affects you. NEURONTIN can slow your thinking and motor skills.
What are the possible side effects of NEURONTIN?
NEURONTIN may cause serious side effects including:
See "What is the most important information I should know about NEURONTIN?"
- problems driving while using NEURONTIN. See "What I should avoid while taking Neurontin?"
- sleepiness and dizziness, which could increase the occurrence of accidental injury, including falls
- The most common side effects of NEURONTIN include:
- lack of coordination
- viral infection
- feeling drowsy
- nausea and vomiting
- difficulty with speaking
- swelling, usually of legs and feet
- feeling tired
- jerky movements
- difficulty with coordination
- double vision
- unusual eye movement
Tell your healthcare provider if you have any side effect that bothers you or that does not go away.
These are not all the possible side effects of NEURONTIN. For more information, ask your healthcare provider or pharmacist.
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
How should I store NEURONTIN?
- Store NEURONTIN Capsules and Tablets between 68°F to 77°F (20°C to 25°C).
- Store NEURONTIN Oral Solution in the refrigerator between 36°F to 46°F (2°C to 8°C).
Keep NEURONTIN and all medicines out of the reach of children.
General information about the safe and effective use of NEURONTIN
Medicines are sometimes prescribed for purposes other than those listed in a Medication Guide. Do not use NEURONTIN for a condition for which it was not prescribed. Do not give NEURONTIN to other people, even if they have the same symptoms that you have. It may harm them.
This Medication Guide summarizes the most important information about NEURONTIN. If you would like more information, talk with your healthcare provider. You can ask your healthcare provider or pharmacist for information about NEURONTIN that was written for healthcare professionals.
For more information go to http://www.pfizer.com or call 1-800-438-1985.
What are the ingredients in NEURONTIN?
Active ingredient: gabapentin
Inactive ingredients in the capsules: lactose, cornstarch, talc, gelatin, titanium dioxide and FD&C Blue No. 2.
The 300-mg capsule shell also contains: yellow iron oxide.
The 400-mg capsule shell also contains: red iron oxide, and yellow iron oxide.
Inactive ingredients in the tablets: poloxamer 407, copovidone, cornstarch, magnesium stearate, hydroxypropyl cellulose, talc, and candelilla wax
Inactive ingredients in the oral solution: glycerin, xylitol, purified water, and artificial flavor.
This Medication Guide has been approved by the U.S. Food and Drug Administration.
This product’s label may have been updated. For current full prescribing information, please visit www.pfizer.com.
A lethal dose of gabapentin was not identified in mice and rats receiving single oral doses as high as 8000 mg/kg. Signs of acute toxicity in animals included ataxia, labored breathing, ptosis, sedation, hypoactivity, or excitation.
Acute oral overdoses of NEURONTIN up to 49 grams have been reported. In these cases, double vision, slurred speech, drowsiness, lethargy, and diarrhea were observed. All patients recovered with supportive care. Coma, resolving with dialysis, has been reported in patients with chronic renal failure who were treated with NEURONTIN.
Gabapentin can be removed by hemodialysis. Although hemodialysis has not been performed in the few overdose cases reported, it may be indicated by the patient’s clinical state or in patients with significant renal impairment.
If overexposure occurs, call your poison control center at 1-800-222-1222.
The active ingredient in NEURONTIN capsules, tablets, and oral solution is gabapentin,which has the chemical name 1-(aminomethyl)cyclohexaneacetic acid.
The molecular formula of gabapentin is C9H17NO2 and the molecular weight is 171.24. The structural formula of gabapentin is:
Gabapentin is a white to off-white crystalline solid with a pKa1 of 3.7 and a pKa2 of 10.7. It is freely soluble in water and both basic and acidic aqueous solutions. The log of the partition coefficient (n-octanol/0.05M phosphate buffer) at pH 7.4 is –1.25.
Each Neurontin capsule contains 100 mg, 300 mg, or 400 mg of gabapentin and the following inactive ingredients: lactose, cornstarch, talc, gelatin, titanium dioxide, FD&C Blue No. 2, yellow iron oxide (300 mg and 400 mg only), and red iron oxide (400 mg only).
Each Neurontin tablet contains 600 mg or 800 mg of gabapentin and the following inactive ingredients: poloxamer 407, copovidone, cornstarch, magnesium stearate, hydroxypropyl cellulose, talc, and candelilla wax
Neurontin oral solution contains 250 mg of gabapentin per 5 mL (50 mg per mL) and the following inactive ingredients: glycerin, xylitol, purified water, and artificial cool strawberry anise flavor.