Gabapentin: Uses, Dosage, Side Effects and More

Gabapentin

The basics:

Gabapentin is an anti-epileptic drug. It is also known as an anticonvulsant drug. This medicine helps to normalize the way nerve impulses travel along with the nerve cells which helps prevent or treat seizures. This drug helps decrease abnormal excitement in the brain.

Moreover, gabapentin works in the brain to prevent seizures and can also relieve pain for certain conditions in the nervous system. It is not used for routine pain caused by minor injuries or arthritis.

However, while it helps control partial seizures (convulsions) in epilepsy, it cannot cure epilepsy and will only work to control seizures for as long it is taken.

This medicine is available only with a doctor’s prescription.

Doctors can prescribe gabapentin to treat epilepsy in people older than 12, and partial seizures in children ages 3 to 12.

The Food and Drug Administration (FDA) approved it in 1993 under the brand name Neurontin for the drug manufacturer Pfizer.

In 2003, the FDA approved generic gabapentin. There are several drug companies that manufacture it.

Neurontin is the most common and known brand of gabapentin.

Uses:

  • Seizure control and prevention
  • It can also relieve the pain of postherpetic neuralgia (PHN) in adults. It does this by changing the way the body senses pain. PHN is a common complication of shingles. This condition affects nerve fibers and the skin, causing burning pain. It lasts long after the rash and blisters of shingles disappear.
  • Treatment and prevention of hot flashes in women. Hot flashes are sudden strong feelings of heat and sweating. Breast cancer patients and menopausal women use gabapentin.
  • Pain relief for diabetic neuropathy. Diabetic neuropathy is numbness or tingling due to nerve damage in people who have diabetes.
  • It can also help with restless legs syndrome. RLS is a condition that causes discomfort in the legs and a strong urge to move the legs, especially at night and when sitting or lying down.

Forms:

  • Capsule
  • Tablet
  • Oral solution
  • Extended-release tablet
  • Suspension

Gabapentin capsules, tablets, and oral solution are used to help control certain types of seizures in people who have epilepsy.

In addition, the capsules, tablets, and oral solution are also used to relieve the pain of postherpetic neuralgia.

Gabapentin extended-release tablets are used to treat restless legs syndrome too.

Dosage:

For postherpetic neuralgia: A normal adult dose usually starts at 300 milligrams (mg), and doctors may increase the dose to up to 1,800 mg a day.

For epilepsy: A typical adult dose may range from 900 to 1,800 mg a day.

Doctors usually start a patient off with a low dose of gabapentin and then increase the dose gradually until they get to a level that works best for them.

Instructions:

Gabapentin comes as a capsule, a tablet, an extended-release (long-acting) tablet, and an oral solution (liquid) to take by mouth. Gabapentin capsules, tablets, and oral solution are usually taken with a full glass of water (8 ounces [240 milliliters]), with or without food, three times a day.

These medications should be taken at evenly spaced times throughout the day and night; no more than 12 hours should pass between doses.

Regular-release tablets, capsules, and liquid gabapentin are usually taken in three equal doses three times a day.

While the extended-release tablet is taken with food once daily at about 5 PM.

It is essential to follow the directions listed on prescription labels carefully. Doctors and pharmacists can help explain any parts that are difficult to follow or understand.

Take gabapentin exactly as directed. Do not take more or less of it or take it more often than prescribed.

Gabapentin extended-release tablets cannot be substituted for another type of gabapentin product. Be sure to get only the type of gabapentin that was prescribed by the doctor.

Importantly, swallow the extended-release tablets whole and not cut or crushed.

If it is instructed that only one-half of a regular tablet should be taken as part of the dose. The other half-tablet can be used as part of the next dose. Properly dispose of any half-tablets that have not used within several days of breaking them.

Response:

Peak concentrations of gabapentin (immediate-release) occur within 2 to 3 hours. Gabapentin may improve sleep problems due to nerve pain within a week.

However, it may take up to two weeks for symptom relief from nerve pain to occur. A decrease in seizure frequency is usually evident within a few weeks.

Interactions:

It’s very important for a patient to let their doctor know about all the drugs they are taking. These include illegal or recreational drugs, over-the-counter medications, herbs, or supplements.

These are the types of drugs, tests, and substances that gabapentin interacts with and may cause problems:

  • Opiate pain medications
  • Naproxen
  • Medications used for heartburn
  • Drinking alcohol may make some side effects more severe
  • Medicines that can cause sedation, including Benadryl, sleep aids, muscle relaxants
  • Results of dipstick tests may become affected

Side effects:

Some of these side effects may go away as the body adjusts to the medication. If side effects persist and may pose a threat to a patient’s safety, consider scheduling another appointment to have it checked again by doctors.

Common side effects may include the following:

1. Sleepiness, drowsiness or dizziness

These are more likely to occur when a patient has started taking the drug. Driving or operating machinery is not advised while taking gabapentin or at least while these side effects are present. These side effects may also increase the risk of falling and impair judgment.

If dizziness and sleepiness do not go away, have a doctor check it. The dosage may need to be adjusted along with slowly weaning the patient off it.

2. Fatigue

One of the most common side effects seen in patients taking this medicine is fatigue. They report experiencing mild to moderate levels of fatigue.

Gabapentin can cause fatigue because they affect chemicals in the brain called neurotransmitters. The nerves use them to carry messages to each other. Some of them control how awake or sleepy a person may feel.

3. Clumsiness while walking or gait disturbance, feeling wobbly, balance problems

Movement coordination tends to present more in elderly individuals, who are at high risk for falling injuries.

Uncoordinated movement may occur as the result of a combination of dizziness and weakness. The legs may also be affected as the medicine works to relieve the pain associated with peripheral neuropathy. This can make walking difficult.

4. Visual changes, including double vision and blurry vision

Blurry vision refers to a lack of sharpness of vision resulting in the inability to see fine detail. While double vision occurs when a person sees a double image where there should only be one. The two images can be side by side, on top of one another, or both.

About 1-7% of people who take gabapentin do report double or blurred vision as its side effects.

5. Tremors, trembling or shaking

The brain’s response to the chemicals in the medication causes these tremors. The trembling or shaking are rhythmic and uncontrollable movements in some parts of the body. They can occur when the body moves a certain way or are in certain positions.

6. Runny nose

Gabapentin may cause flu-like side effects like a runny nose. When there is a discharge or fluid coming from the nasal passages, a runny nose is present. It is often a watery, clear liquid but may be thicker and sticky. 

4. Weight gain

2% to 3% of patients have experienced weight gain while taking this medicine.

Drugs can affect weight in many ways, and it isn’t always by increasing fat storage. Some medicine increases appetite or creates cravings for certain types of foods like those high in carbohydrates or fat. Other medications may slow down metabolism or cause fluid retention.

However, the effect of prescription drugs (like gabapentin) on body weight is complicated.

8. Indigestion or nausea

Nausea may be an unpleasant side effect when there is sudden discontinuation of the drug.

Indigestion is a gastrointestinal symptom. Pain or discomfort in the upper abdomen (dyspepsia) or burning pain behind the breastbone (heartburn) describes indigestion.

If indigestion becomes severe, doctors will often recommend changes in diet to combat them while on gabapentin.

9. Nervousness

Nervousness can make it difficult to relax and the heart beats much faster than it usually does. Stress is often the cause of this.

The abrupt discontinuation in taking the drug may cause this side effect.

10. Dry mouth

This is a rare side effect that should not require medical attention. Dry mouth occurs when the salivary glands in the mouth do not produce enough saliva to keep the mouth wet.

11. Memory loss/dementia

Some patients experience short-term memory loss and mental disorientation.

Anticonvulsant medications are believed to limit seizures by dampening the flow of signals within the central nervous system. The drugs control seizures by decreasing brain activity that allows it to communicate with your central nervous system and can cause memory loss.

Memory loss caused by gabapentin is considered reversible.

Patients of different ages, however, may be affected differently and other factors may also cause memory loss.

12. Headache

This is another common side effect of abrupt discontinuation of gabapentin

Subsequently, there is also the truth that there are medicines used to treat headaches that can actually cause them. Rebound headache or medication overuse headache is such a condition.

Furthermore, this happens when using medicines for pain relief over the course of several times a week.

When the medication wears off, the headache or pain comes back which would lead a patient to take even more medicine.

13. Diarrhea

Diarrhea is a common side effect of taking gabapentin.

This is because most of the medications prescribed for nerve and other types of pain have this effect.

14. Swelling of hands or feet

Swelling in the legs caused by the pooling of fluid or edema is a common side effect of medications. This condition is a common side effect of gabapentin.

Patients taking gabapentin may experience swelling in the feet and ankles. Gabapentin may cause lower leg swelling.  8% of patients with shingles who are taking gabapentin reported swelling. The presence of lower leg swelling may cause discomfort and impair walking. 

15. Dry and itchy eyes

This is a less common side effect of the drug gabapentin.

Insufficient tear production causes this condition. This can cause an uncomfortable sensation.

In addition, the eyes may also sting, burn or itch.

Serious side effects include:

1. Depression and suicidal thoughts/ideations

These are serious side effects of taking gabapentin.

Gabapentin may increase the risk of depression.

Suicidal ideations usually happen after only a week of treatment. Young adults under the age of 24 are the most susceptible.

This is a very serious side effect. It should be immediately reported to the patient’s healthcare provider.

2. Aggressive behavior

Aggression and other behavioral problems are another serious side effect of taking gabapentin.

It should be noted giving gabapentin to children 3 to 12 years of age may also cause other emotional changes. Problems with concentration, restlessness, changes in school performance, and hyperactivity can also be seen.

Contributing causes may include pharmacological activity, patient characteristics, individual susceptibility, forced normalization, dosage, and other drug interactions.

3. Fever or swelling of lymph nodes

These may be symptoms of rare hypersensitivity reactions that may occur while taking gabapentin.

Hypersensitivity is reactions that occur when the normally protective immune system responds abnormally, potentially harming the body.

Seek urgent medical advice if this side effect becomes apparent.

4. Severe rash

The appearance of severe rashes is another sign that the body is having an adverse reaction to the medication.

Facial swelling may also occur.

Although these side effects are rare, they still pose a big cause for worry. These are signs of possible life-threatening allergic reactions and would need immediate medical attention.

5. Difficulty breathing

This is another rare but very serious side effect of the drug gabapentin.

The FDA warns that this drug may cause breathing difficulties in patients who have respiratory risk factors, such as using opioids or other central nervous system depressants, having an underlying respiratory condition like chronic obstructive pulmonary disease, or being elderly.

If this side effect appears, seek immediate medical help.