What are the Ingredients in Gabapentin ?

Active ingredient: gabapentin

Gabapentin 800 mg Tab-IVA
Gabapentin 800 mg Tab-IVA

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.

Gabapentin May Cause Serious or Life-Threatening Allergic Reactions

Gabapentin 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.

Gabapentin 800 mg Tab-IVA
Gabapentin 800 mg Tab-IVA

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
      • hives
      • difficulty breathing
      • fever
      • 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.

Gabapentin – Dosage information for RLS, Epilepsy and Postherpetic Neuralgia

The Gabapentin dosage differs in each individual depending upon the age of the person, current medical condition and patient’s tolerance to the medicine. This article will help you know about the general Gabapentin dosage information for RLS, Epilepsy and Postherpetic Neuralgia.

Again the dosage can differ thus you should take Gabapentin as recommended by your doctor.

Normal Dose for Epilepsy- In Adults

Initial dose: 300mg to be taken orally on first day

300 mg to be taken orally two times a day on the second day

300mg to be taken orally thrice a day on third day

Maintenance dose: 300-600mg to be taken orally thrice a day

Maximum dose: 3600mg to be taken orally daily in 3 split doses

Maximum time gap between doses in a schedule wherein the patient is taking the medicine thrice a day should not be more than 12 hours

Note:  Gabapentin can be taken with/without food

If you have not used the half tablets (broken) within 28 days after breaking, the tablet should be disposed.

Normal Dose for Postherpetic Neuralgia – In Adults

Initial dose: 300mg to be taken orally on first day

300 mg to be taken orally two times a day on the second day

300mg to be taken orally thrice a day on third day

The dosage can be adjusted as required

Maintenance dose: 1800mg/day (600mg to be taken orally three times a day)

Note: Gabapentin can be taken with/without food

If you have not used the half tablets (broken) within 28 days after breaking, the tablet should be disposed

Gabapentin available under the brand name GRALISE(R)

Maintenance dose: GRALISE(R) should be adjusted to 1800mg to be taken orally once in a day during meal.

Recommended dosage schedule

Day 1: 300 mg to be taken orally with meal in the evening

Day 2: 600 mg to be taken orally with meal in the evening

From Day 3 to day 6: 900 mg to be taken orally with meal in the evening

From Day 7 to day 10: 1200 mg to be taken orally with meal in the evening

From Day 11 to day 14: 1500 mg to be taken orally with meal in the evening

Day 15: 1800 mg to be taken orally with meal in the evening

Gabapentin (enacarbil extended release tablets) are sold under brand name HORIZANT (R)

The recommended dosage – 600 mg to be taken orally twice a day

Therapy should be started at a dose of 600mg to be taken orally in the morning till 3 days of therapy and can be increased up to 600mg to be taken twice a day and 1200 mg/day on fourth day.

Normal Dose for Restless Leg Syndrome- In Adults

600mg to be taken orally once daily during 5 PM with food

The medication is used to treat mild to severe RLS in adults

The above dosage information is general dosage information that can vary from person to person depending upon his/her medical condition and age. Your doctors can advice the right dose for you. [1]

Appropriate Gabapentin Dosing for Neuropathic Pain

Neuropathic pain is a chronic debilitating pain syndrome that is complex to treat. Current medication management for neuropathic pain includes select neuromodulating agents such as anticonvulsants, serotonin norepinephrine reuptake inhibitors, tricyclic antidepressants, and certain opioids.1,2 Gabapentin remains among the most commonly used anticonvulsants for neuropathic pain.

The established therapeutic dosing for gabapentin in neuropathic pain trials is 1800-3600 mg/day in 3 divided doses in patients with normal renal function.3 This means the minimum effective dose is 600 mg 3 times a day. Renal adjustments are recommended in patients with CrCl below 60 mL/min. For patients on dialysis, gabapentin can often be 3 times weekly following dialysis.4,5

Several cross-sectional studies have reported gabapentin being used in subtherapeutic doses among most patients.6-8 In a retrospective analysis of 939 patients with post-herpetic neuralgia, the mean daily dose of gabapentin was 826 mg.7 In another 2-year retrospective study of 151 veterans with various neuropathic pain syndromes, the median daily dose for gabapentin was 900 mg.8 In both studies, the most prevalent gabapentin dosing was half the therapeutic dosing.

The cornerstones of effective pharmacotherapy are the right patient, the right drug, and the right dose. If an analgesic medication is being used at a suboptimal dose, oftentimes a knee-jerk reaction is to add another analgesic for synergy.

While this may well be indicated under appropriate circumstances, it is inappropriate without maximizing the dose of each single agent with careful attention to dose titration in order to minimize toxicity of each add-on. Consider for example a patient who starts low dose gabapentin that was not properly titrated, returns for follow-up and is given an additional prescription for duloxetine for neuropathic pain since gabapentin “does not work,” assuming there are no tolerability issues. This adds to polypharmacy, increased costs, and the pain remains inadequately treated.

Pharmacists as medication experts can collaborate with prescribers to optimize the rational use of gabapentin in neuropathic pain. First, let’s take a look into the pharmacology of gabapentin.

Gabapentin is a gaba aminobutyric acid (GABA) analogue anticonvulsant but does not exhibit any significant agonistic effects at the GABA receptor.  Gabapentin inhibits the alpha-2-delta subunit of the N-type voltage-gated calcium channels. Receptor binding causes presynaptic inhibition of excitatory neurotransmitter release (i.e. glutamate) thereby attenuating neuropathic pain.

Gabapentin’s counterpart, pregabalin, shares the same mechanism of action but there are key pharmacologic differences between both medications. Gabapentin has saturable, non-linear absorption kinetics, where bioavailability decreases as the dose increases.

Following oral administration, gabapentin’s bioavailability is 60%, 47%, 34%, and 33%, following 900, 1200, 2400, and 3600 mg/day in 3 divided doses, respectively. On the other hand, pregabalin has ≥90% bioavailability irrespective of the dose, leading to more predictable kinetics. Pregabalin boasts a binding affinity for the alpha-2-delta receptor that is six times greater than that of gabapentin.

What Every Patient Should Know
Patients should be aware of the therapeutic dosing for neuropathic pain to establish realistic expectations and improve compliance and likelihood of remaining on therapy. The conversation may be as follows: “Gabapentin may reduce nerve pain at 600 mg 3 times a day but patients usually start on a low dose to make sure they tolerate it and is then increased slowly to give the body a chance to get used to it.  If dose increases along the titration cause intolerable side effects such as dizziness or drowsiness, this can often be overcome by reducing back to the previous dose and escalating more slowly over a longer period of time.” Patients should be encouraged to follow-up with their prescriber for continued titration.

Gabapentin Is Not a “PRN” Medication
Another mishap with gabapentin that contributes to treatment failure is when patients take it on an as needed basis. Gabapentin exhibits its activity by impeding calcium trafficking and is required to be present at the alpha-2-delta receptor for 17-20 hours in order to ensure efficacy.11 Therefore, gabapentin needs to be taken around the clock to exert its analgesic effects rather than used on an as needed basis. This is another area that pharmacists can educate patients at initiation of therapy to improve compliance.

Gabapentin is used for Restless legs syndrome

What is restless legs syndrome?

Restless legs syndrome (RLS), also called Willis-Ekbom Disease, causes unpleasant or uncomfortable sensations in the legs and an irresistible urge to move them.  Symptoms commonly occur in the late afternoon or evening hours, and are often most severe at night when a person is resting, such as sitting or lying in bed.

They also may occur when someone is inactive and sitting for extended periods (for example, when taking a trip by plane or watching a movie).  Since symptoms can increase in severity during the night, it could become difficult to fall asleep or return to sleep after waking up.  Moving the legs or walking typically relieves the discomfort but the sensations often recur once the movement stops.

RLS is classified as a sleep disorder since the symptoms are triggered by resting and attempting to sleep, and as a movement disorder, since people are forced to move their legs in order to relieve symptoms.  It is, however, best characterized as a neurological sensory disorder with symptoms that are produced from within the brain itself.

RLS is one of several disorders that can cause exhaustion and daytime sleepiness, which can strongly affect mood, concentration, job and school performance, and personal relationships.  Many people with RLS report they are often unable to concentrate, have impaired memory, or fail to accomplish daily tasks.  Untreated moderate to severe RLS can lead to about a 20 percent decrease in work productivity and can contribute to depression and anxiety.  It also can make traveling difficult.

It is estimated that up to 7-10 percent of the U.S. population may have RLS.  RLS occurs in both men and women, although women are more likely to have it than men.   It may begin at any age.  Many individuals who are severely affected are middle-aged or older, and the symptoms typically become more frequent and last longer with age.

More than 80 percent of people with RLS also experience periodic limb movement of sleep (PLMS).  PLMS is characterized by involuntary leg (and sometimes arm) twitching or jerking movements during sleep that typically occur every 15 to 40 seconds, sometimes throughout the night.  Although many individuals with RLS also develop PLMS, most people with PLMS do not experience RLS.

Fortunately, most cases of RLS can be treated with non-drug therapies and if necessary, medications.

Gabapentin in the management of restless legs syndrome (RLS) has been evaluated in small controlled trials, demonstrating benefits compared with placebo. Gabapentin enacarbil is FDA-approved for the treatment of RLS .

The American Academy of Sleep Medicine (AASM) guidelines regarding RLS management consider gabapentin effective based on low-level evidence and note that patients with pain symptoms appeared to benefit most.

The benefit-risk ratio is unclear. The European Federation of Neurological Societies/European Neurological Society/European Sleep Research Society (EFNS/ENS/ESRS) Task Force guidelines consider gabapentin effective for short-term management and possibly effective for long-term management of RLS.

Additional study is needed to establish optimal dosing. Based on the International Restless Legs Syndrome Study Group, European Restless Legs Syndrome Study Group, and RLS Foundation (IRLSSG/EURLSSG/RLS-F) guidelines for the prevention and treatment of dopaminergic augmentation in restless legs syndrome, α2δ ligands (eg, gabapentin) are effective and should be considered for the initial treatment of patients with RLS due to their minimal risk of augmentation.

Additionally, patients who experience augmentation on dopaminergic agents may benefit from a switch to α2δ ligands (eg, gabapentin). However, the guidelines note that long-term studies are needed.

How is restless legs syndrome treated?

RLS can be treated, with care directed toward relieving symptoms.  Moving the affected limb(s) may provide temporary relief.  Sometimes RLS symptoms can be controlled by finding and treating an associated medical condition, such as peripheral neuropathy, diabetes, or iron deficiency anemia.

Iron supplementation or medications are usually helpful but no single medication effectively manages RLS for all individuals.  Trials of different drugs may be necessary.  In addition, medications taken regularly may lose their effect over time or even make the condition worse, making it necessary to change medications.

Treatment options for RLS include:

Lifestyle changes.  Certain lifestyle changes and activities may provide some relief in persons with mild to moderate symptoms of RLS.  These steps include avoiding or decreasing the use of alcohol and tobacco, changing or maintaining a regular sleep pattern, a program of moderate exercise, and massaging the legs, taking a warm bath, or using a heating pad or ice pack.  There are new medical devices that have been cleared by the U.S. Food & Drug Administration (FDA), including a foot wrap that puts pressure underneath the foot and another that is a pad that delivers vibration to the back of the legs.  Aerobic and leg-stretching exercises of moderate intensity also may provide some relief from mild symptoms.

Iron.  For individuals with low or low-normal blood tests called ferritin and transferrin saturation, a trial of iron supplements is recommended as the first treatment.  Iron supplements are available over-the-counter.  A common side effect is upset stomach, which may improve with use of a different type of iron supplement.  Because iron is not well-absorbed into the body by the gut, it may cause constipation that can be treated with a stool softeners such as polyethylene glycol.  In some people, iron supplementation does not improve a person’s iron levels.  Others may require iron given through an IV line in order to boost the iron levels and relieve symptoms.

Anti-seizure drugs.  Anti-seizure drugs are becoming the first-line prescription drugs for those with RLS.  The FDA has approved gabapentin enacarbil for the treatment of moderate to severe RLS, This drug appears to be as effective as dopaminergic treatment (discussed below) and, at least to date, there have been no reports of problems with a progressive worsening of symptoms due to medication (called augmentation).  Other medications may be prescribed “off-label” to relieve some of the symptoms of the disorder.

Other anti-seizure drugs such as the standard form of gabapentin and pregabalin can decrease such sensory disturbances as creeping and crawling as well as nerve pain.  Dizziness, fatigue, and sleepiness are among the possible side effects.  Recent studies have shown that pregabalin is as effective for RLS treatment as the dopaminergic drug pramipexole, suggesting this class of drug offers equivalent benefits.

Dopaminergic agents.  These drugs, which increase dopamine effect, are largely used to treat Parkinson’s disease.  They have been shown to reduce symptoms of RLS when they are taken at nighttime.  The FDA has approved ropinirole, pramipexole, and rotigotine to treat moderate to severe RLS.  These drugs are generally well tolerated but can cause nausea, dizziness, or other short-term side effects.  Levodopa plus carbidopa may be effective when used intermittently, but not daily.

Although dopamine-related medications are effective in managing RLS symptoms, long-term use can lead to worsening of the symptoms in many individuals.  With chronic use, a person may begin to experience symptoms earlier in the evening or even earlier until the symptoms are present around the clock.  Over time, the initial evening or bedtime dose can become less effective, the symptoms at night become more intense, and symptoms could begin to affect the arms or trunk.  Fortunately, this apparent progression can be reversed by removing the person from all dopamine-related medications.

Another important adverse effect of dopamine medications that occurs in some people is the development of impulsive or obsessive behaviors such as obsessive gambling or shopping.  Should they occur, these behaviors can be improved or reversed by stopping the medication.

Opioids.  Drugs such as methadone, codeine, hydrocodone, or oxycodone are sometimes prescribed to treat individuals with more severe symptoms of RLS who did not respond well to other medications.  Side effects include constipation, dizziness, nausea, exacerbation of sleep apnea, and the risk of addiction; however, very low doses are often effective in controlling symptoms of RLS.

Benzodiazepines.  These drugs can help individuals obtain a more restful sleep.  However, even if taken only at bedtime they can sometimes cause daytime sleepiness, reduce energy, and affect concentration.  Benzodiazepines such as clonazepam and lorazepam are generally prescribed to treat anxiety, muscle spasms, and insomnia.  Because these drugs also may induce or aggravate sleep apnea in some cases, they should not be used in people with this condition.  These are last-line drugs due to their side effects.

Gabapentin is Used for Neuropathic Pain (other than Postherpetic Neuralgia)

In a meta-analysis of trials evaluating the treatment of neuropathic pain, including painful polyneuropathy and spinal cord injury pain, gabapentin was shown to be safe and effective .

Data from meta-analyses support the use of immediate-release gabapentin for reducing pain by more than 50% in diabetic neuropathy.

 

Diabetic Peripheral Neuropathy
Diabetic Peripheral Neuropathy

Data from a limited number of clinical trials support the use of extended-release gabapentin in reducing pain by more than 50% and improving sleep in diabetic neuropathy.

Gabapentin (Neurontin) has FDA indication to treat postherpetic neuralgia and partial onset seizures.  Controlled clinical trials in diabetic neuropathy and postherpetic neuralgia show that gabapentin at 2400-3600 mg/day has a similar efficacy to tricyclic antidepressants and carbamazepine.  Consistent, though less compelling clinical evidence supports its use for neuropathic cancer pain, pain associated with HIV infection, chronic back pain and others (readers wanting more in depth research findings are urged to consult Reference 1).

Due to this emerging evidence, it is widely used for the treatment of neuropathic pain.  The exact mechanism and site of action of gabapentin is unknown.   Gabapentin is generally well-tolerated, easily titrated, has few drug interactions, and does not require laboratory monitoring.  However, cost may be a limiting factor for some patients.

Patients suitable for gabapentin should have a clear neuropathic pain syndrome, characterized by sharp, shooting, lancinating and/or burning pain, in a nerve root (radicular) or stocking/glove distribution. See Fast Fact #289 for a comparison of gabapentin with pregabalin a similar neuropathic analgesic.

Adult Dosing    Gabapentin is started at low doses (100 mg to 300 mg total daily) and increased by 100 – 300 mg every 1-3 days to effect.  A typical schedule might be: day 1-2: 300 mg nightly; day 3-4: 300 mg twice daily; day 5-7: 600 mg twice daily; day 8 onwards: 600 mg three times a day.  The usual effective total daily dose is 900-3600 mg, administered in three divided doses per day.  Titration should proceed more slowly in elderly patients. If gabapentin is discontinued, it should be done over a minimum of a week to prevent withdrawal seizures.

Pediatric Use    There is limited data available assessing its effectiveness in neuropathic pain in children. The American Pain Society recommends that gabapentin be considered for pediatric neuropathic pain especially when concurrent analgesics are found to be too sedating.  Their recommended initial dose is 2 mg/kg/day with a usual dosage range of 8 to 35 mg/kg/day divided into 3 daily doses.

Dosing in Renal Failure   Gabapentin doses must be reduced for patients with renal insufficiency.

  • Creatinine Clearance (CrCl) 30-60 ml/min: maximum daily dose is 1400 mg, divided.
  • CrCl 16-30 ml/min: maximum daily dose is 700 mg, given once daily.
  • CrCl 15ml/min: maximum daily dose is 300 mg, once daily.  Doses should decrease proportionally for CrCl less than 15 ml/min (e.g. 300 mg every other day for a CrCl of ~7.5 ml/min).
  • For patients on hemodialysis a supplemental dose is usually given after dialysis (usually 100-300 mg).

Adverse Reactions    Sedation, confusion, dizziness, and ataxia are the most common side effects, especially with rapid dose titration.  Tolerance to these effects appears to develop within a few days if the dose is held at the highest tolerated dose until symptoms improve or stabilize.

Dosage Formulations    Gabapentin is available in 100 mg, 300 mg, and 400 mg capsules, 600 mg and 800 mg tablets, and as a liquid (250mg/5mL).

Cost    Gabapentin is more expensive than older agents used for neuropathic pain (tricyclic antidepressants and older anti-epileptic drugs such as carbamazepine).  Generic gabapentin is available, although can cost ~$100 for 90 600 mg tablets.

Other Palliative Care Uses of Gabapentin    Small scale published trials have shown efficacy in the treatment of severe chronic hiccups, pruritus, postoperative pain and delirium, restless leg syndrome and hot flashes. Perhaps more compelling is its potential efficacy for chronic cough for which a randomized double-blind placebo controlled trial demonstrated significant improvement in cough-specific quality of life, cough frequency, and cough severity. See Fast Fact #200.

Summary    Gabapentin is a safe and effective adjuvant analgesic for neuropathic pain.  Physicians should become comfortable using and titrating gabapentin in patients with neuropathic pain syndromes.

Based on guidelines from the International Association for the Study of Pain (IASP), European Federation of Neurological Societies (EFNS), and Society of Critical Care Medicine (SCCM), gabapentin is effective and recommended for the management of peripheral neuropathy .

Based on guidelines from the EFNS, IASP, and National Institute for Health and Care Excellence (NICE), gabapentin is effective and recommended as first-line therapy, supported by strong evidence, in the management of diabetic neuropathy.

The IASP guidelines recommend both immediate- and extended-release gabapentin . In contrast, a guideline from the American Academy of Neurology (AAN), American Association of Neuromuscular and Electrodiagnostic Medicine, and American Academy of Physical Medicine and Rehabilitation states that gabapentin is probably effective and should be considered an alternative treatment for painful diabetic neuropathy based on limited benefit in 2 controlled trials.

Similarly, a position statement from the American Diabetes Association (ADA) recommends gabapentin as a second-line option .

Gabapentin Risks during Pregnancy and when Breastfeeding

Neurontin (gabapentin) is an anti-epileptic medication used to treat seizures. Neurontin is used alone or in combination with other medications to treat seizures caused by epilepsy in adults and children who are at least 12 years old. Neurontin is also used to treat nerve pain caused by shingles (herpes zoster).

People who are pregnant, or intend to become pregnant, should tell their doctor before taking gabapentin.

Pregnant women should only take the drug if it is absolutely necessary. However, it is also essential to control seizures while pregnant.

Do not start or stop taking gabapentin for seizure control before talking to the doctor, who will assess the potential risks and benefits.

Gabapentin passes into breast milk, but its effects on babies are unknown. It is best to discuss this issue with a doctor before breastfeeding.

Potential for a drug allergy

Individuals with gabapentin allergies should not take the drug.

Also, the medication may contain other ingredients that can trigger allergy symptoms in some people. Discuss all drug and food allergies with a doctor before taking gabapentin.

Other safety considerations

Because gabapentin can cause drowsiness, anyone taking the drug should exercise caution while driving or using machinery.

Do not take antacids within 2 hours of taking gabapentin, as antacids reduce the body’s ability to absorb the drug.

People should also avoid alcohol or limit their intake while on gabapentin because there is a risk of adverse reactions.

Takeaway

Doctors prescribe gabapentin to control seizures, treat RLS, and reduce nerve pain.

Several types of gabapentin are available, and different forms can treat different medical issues.

The right dosage will vary, depending on the condition and other factors. A doctor can best advise about drug interactions and other safety considerations.

Although gabapentin has the potential to cause several adverse reactions, many people experience no serious side effects.

What is the Side Effects of Gabapentin and Can Gabapentin Causes Erectile Dysfunction ?

I was just hoping that you might have the answer I am hoping for? I started taking gabapentin 300mg twice a day, then 3 times a day, then 600mg twice a day then 3 times a day, now after 2 to 3 years later 800mg 3 times a day.

My doctor says it won’t cause erectile dysfunction but it started very soon after the 300mg 3 times a day. I tried Viagra and Cialis very little help. My wife is very displeased and sometimes thinks it is something to do with her. I know it has nothing to do with her as she is my bride of 24 years and my soul mate spirit. I have very bad pain that the gabapentin used to help with but it now seems it helps no more.

I would rather have my manhood back and my bride be happy and me than be in pain that just won’t go away. To get to the real question, how slowly should I get off the gabapentin and will I ever be able to get back to normal?

I will have to just have to tolerate the pain now that I have my diabetes under control. I rarely have to take my diabetes medicine but a few times a week because it makes my numbers to low and I black out when they get to low.

Usually 82 morning, 92 lunch, and 98 dinner. Any help will be greatly appreciated.

Answers:

Unfortunately gabapentin can cause impotence.

Side effects of the Urogenital System:

Infrequent: urinary tract infection, dysuria, impotence, urinary incontinence, vaginal moniliasis, breast pain, menstrual disorder, polyuria, urinary retention

Rare: cystitis, ejaculation abnormal, swollen penis, gynecomastia, nocturia, pyelonephritis, swollen scrotum, urinary frequency, urinary urgency, urine abnormality.

Talk to your doctor about coming off gabapentin and he/she could put you on some other medicine to help the pain. You don’t have to ween off gabapentin but please get your doctor to monitor you once you are off.

How does Gabapentin Work ?

Gabapentin is a medicine that may be used for the treatment of certain seizure disorders or nerve pain.

Neurontin (gabapentin) is an anti-epileptic medication used to treat seizures. Neurontin is used alone or in combination with other medications to treat seizures caused by epilepsy in adults and children who are at least 12 years old. Neurontin is also used to treat nerve pain caused by shingles (herpes zoster).

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:

NEURONTIN® (gabapentin) - Structural Formula Illustration

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 (noctanol/ 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.

How gabapentin works
How gabapentin works

Experts aren’t sure exactly how gabapentin works, but research has shown that gabapentin binds strongly to a specific site (called the alpha2-delta site) on voltage-gated calcium channels. This action is thought to be the mechanism for its nerve-pain relieving and anti-seizure properties.

Gabapentin  (brand name Horizant) is a prodrug of gabapentin which has been designed to overcome the limitations of gabapentin, such as poor absorption and a short duration of action. Gabapentin enacarbil is effective for restless legs syndrome (RLS) and postherpetic neuralgia (nerve pain that occurs following Shingles).

Gabapentin belongs to the group of medicines known as anticonvulsants.