What Are Gabapentin Interactions and How to Manage it ?

What is gabapentin used for?

Gabapentin is commonly used to treat and prevent seizures in people with epilepsy or to treat nerve pain (postherpetic neuralgia) that can occur after a viral infection called shingles.

Gabapentin may also be used for other conditions as determined by your healthcare provider.

How does gabapentin work (mechanism of action)?

The exact way that gabapentin works for nerve pain or seizures is unknown. Gabapentin may block certain signals from nerves. Seizures are caused by electrical activity in the brain that is not normal. Gabapentin may interfere with the abnormal electrical activity of the brain.

How is gabapentin supplied (dosage forms)?

Gabapentin is available as Gralise, Neurontin, and generic gabapentin in the following dosage forms that are taken by mouth.

100 mg, 300 mg, 400 mg oral capsules
250 mg/5 mL oral solution
100 mg, 300 mg, 400 mg, 450 mg, 600 mg, 750 mg, 800 mg, 900 mg oral tablets

How should I store gabapentin?

Oral Tablet and Oral Capsule. Gabapentin oral tablets and oral capsules should be stored at room temperature, between 68 F to 77 F (20 C to 25 C). It can be exposed to temperatures between 59 F to 86 F (15 C to 30 C), for shorter periods of time, such as when transporting it. Store in a cool, dry place. Keep in a tightly closed container.

Gabapentin is sold under the brand name Neurontin and is available as a generic product as well. (Generic medications are chemically the same as brand-name drugs but may cost less.) Gabapentin is also available as an extended-release tablet that works for a longer length of time; this is the only formulation that is approved for restless legs syndrome.

Gabapentin is taken by mouth and comes in capsule, tablet, and liquid form.

Conditions treated with Gabapentin

Gabapentin is FDA-approved as Neurontin to treat partial seizures in adults and children with epilepsy. Partial seizures are convulsions that originate from a single location in the brain.

Neurontin is also approved to treat a type of nerve pain called postherpetic neuralgia, or PHN. PHN can happen after a person has had shingles, an infection from the same virus as chickenpox that causes a painful rash or blisters. Nerve pain from PHN can last for months, or even longer, after the rash has gone away.

An extended-release form of gabapentin is also FDA-approved to treat PHN.

Another extended-release form of gabapentin is FDA-approved to treat restless legs syndrome. This condition causes unpleasant or uncomfortable sensations in the legs and an irresistible urge to move them around, especially at night, which disrupts sleep.

Off-label uses for gabapentin

Doctors often prescribe gabapentin off-label to treat conditions such as:

pain from diabetic neuropathy, which is numbness or uncomfortable tingling caused by nerve damage from diabetes
nerve pain in the neck and back from conditions such as sciatica, a painful compression of the sciatic nerve
hot flashes, which are sudden feelings of heat and sweating that can happen in women after menopause and in those being treated for breast cancer
mood disorders such as anxiety
alcohol addiction.

Gabapentin Side Effects

What are the most common side effects of gabapentin?

The most common side effects of gabapentin are listed below. Tell your healthcare provider if you have any of these side effects that bother you.

Dizziness
Sleepiness and tiredness
Swelling of hands, legs, or feet
Trouble with balance or coordination
Uncontrollable eye movements
Infection and fever
Nausea and vomiting
Aggressive behavior

There may be other side effects of gabapentin that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of gabapentin?

While less common, the most serious side effects of gabapentin are described below, along with what to do if they happen.

Severe Allergic Reactions. Gabapentin can cause allergic reactions, including DRESS, which can be serious. DRESS stands for Drug Reaction with Eosinophilia and Systemic Symptoms. It is also sometimes called multiorgan hypersensitivity. This is a reaction that can affect multiple parts of the body, including your liver, kidneys, and heart. Stop taking gabapentin and get help right away if you have any of the following symptoms of a serious allergic reaction.

Swelling of the face, lips, mouth, tongue, or throat
Breathing problems or wheezing
Racing heart
Fever or general ill feeling
Swollen lymph nodes
Trouble swallowing or throat tightness
Itching, skin rash, or pale red bumps on the skin called hives
Nausea or vomiting
Dizziness, feeling lightheaded, or fainting
Stomach cramps
Joint pain
Swelling in your feet, ankles, or legs
Dark-colored urine
Your skin or the whites of your eyes turning yellowish in color (also called jaundice)

Breathing Problems. Gabapentin may cause slow and shallow breathing, especially if you have breathing problems from another condition or take other medicines that can slow your breathing. See the Interactions section for more details. Tell your healthcare provider if you develop severe sleepiness, especially when you start gabapentin or when your dose is increased. Get emergency help if you have any of the following symptoms.

Changes in the color of your skin, including bluish color to your lips and fingernails
Confusion
Shortness of breath
Feeling dizzy, lightheaded, or fainting
Changes in your heart rate or rhythm, such as a fast, slow, pounding or skipping heartbeat
Fast breathing or very slow breathing

Sleepiness, Dizziness, and Driving Impairment. Gabapentin may cause dizziness and sleepiness and can impair your ability to safely drive. Do not drive or do other activities that require alertness or coordination like operating heavy machinery until you know how gabapentin affects you. How long gabapentin may impair your ability to drive is unknown. Ask your healthcare provider when you can drive or do other activities.

Suicidal Thoughts and Actions. Gabapentin may cause suicidal thoughts or actions in a small number of people. If you are about to harm yourself, call 911 or call or text 988, the Suicide & Crisis Lifeline. Call your healthcare provider right away if you have any of the following symptoms.

New or increased thoughts of suicide or death
Suicide attempt
New or increased feelings of anxiety, depression, or other unusual changes in mood or behavior

Changes in Behavior and Thinking. Children between 3 and 12 years of age taking certain forms of gabapentin may have emotional changes; school performance changes; or develop aggressive behavior, restlessness, hyperactivity, or concentration problems. Tell your child’s healthcare provider if you notice changes in your child’s behavior or thinking.

Warnings & Precautions

Who should not use gabapentin?

Allergies to Ingredients. People who are allergic to any of the following should not take gabapentin.

Gralise
Neurontin
Gabapentin
Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all the ingredients in the specific gabapentin products they stock.

What should I know about gabapentin before using it?

Do not take gabapentin unless it has been prescribed to you by a healthcare provider. Take it as prescribed. Different forms of gabapentin are not interchangeable even if the strength is the same. Always follow the instructions given by your healthcare provider, and take the specific medicine prescribed to you.

Do not stop taking gabapentin without talking to your healthcare provider. Stopping gabapentin suddenly can cause side effects, including seizures. If you need to stop taking gabapentin, your healthcare provider will give you instructions on how to stop the medicine.\

Do not share gabapentin with other people, even if they have the same condition as you. It may harm them.

Keep gabapentin out of the reach of children. As the oral liquid must be kept in a refrigerator, take special precautions to keep it away from children who also use the refrigerator.

Some forms of gabapentin need to be taken with food. If you are unsure whether or not to take your medicine with food, ask your healthcare provider.

Do not chew, cut, or crush gabapentin capsules. Swallow them whole with water.

Some gabapentin tablets should not be chewed, cut, or crushed. Ask your pharmacist or healthcare provider about the best way to take your medicine. If you are told that it is okay to split a gabapentin tablet in half, take the other half at the time you are supposed to take your next dose. Throw away any unused half tablets within 28 days.

People who are 65 years of age or older can be at a greater risk for some side effects of gabapentin. Talk to your healthcare provider about your risks if you are in this age group.

For gabapentin oral liquid, use an accurate measuring device to measure your dose. A household spoon is not an accurate measuring device and may cause you to take the wrong dose. Ask your pharmacist to recommend an appropriate measuring device.

What should I tell my healthcare provider before using gabapentin?

Tell your healthcare provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if gabapentin is right for you.

Current and Past Health Conditions. Tell your healthcare provider if you have any of the following.

Kidney problems or on dialysis
Breathing problems
Diabetes
Seizures (if you are taking gabapentin for another reason)

Mental Health Problems. Tell your healthcare provider about any recent and current mental health problems, especially if you have had thoughts of suicide, have ever attempted suicide, or have depression or mood problems.

Other Medicines and Supplements. Gabapentin may interact with other medicines and supplements. Before taking gabapentin, tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how gabapentin could affect pregnancy or harm an unborn baby. Tell your healthcare provider if you are or plan to become pregnant. Your healthcare provider will advise you if you should take gabapentin while you are pregnant or trying to get pregnant. You can register for the North American Antiepileptic Drug Pregnancy Registry by calling 888-233-2334 if you become pregnant. This registry collects safety information about the use of anticonvulsant medicines during pregnancy.

Breastfeeding. Gabapentin passes into breast milk. Tell your healthcare provider if you are breastfeeding or plan to breastfeed. Your healthcare provider will advise you if you should take gabapentin while breastfeeding.

Overdose/Missed Dose

What should I do if I accidentally use too much gabapentin?

If you or someone else has taken too much gabapentin, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of gabapentin?

If you miss a dose, take it as soon as you remember with food. If it is almost time for your next dose, skip the missed dose and only take the next dose at your scheduled time. Do not take double or extra doses.

Gabapentin Interaction

Gabapentin can interact with other medications, supplements, and substances, potentially leading to reduced effectiveness or increased risk of side effects.

Understanding these interactions is crucial for safe use. Here’s a breakdown of gabapentin interactions:

1. CNS Depressants

Examples: Alcohol, benzodiazepines (e.g., diazepam, lorazepam), opioids (e.g., morphine, oxycodone), sleep aids, antihistamines (e.g., diphenhydramine), muscle relaxants.
Interaction: Gabapentin can increase the sedative effects of these substances, leading to excessive drowsiness, dizziness, impaired coordination, and respiratory depression.
Advice: Avoid alcohol and use other central nervous system (CNS) depressants cautiously. Discuss with your doctor if you are taking any sedative medications.

2. Antacids Containing Aluminum or Magnesium

Examples: Maalox, Mylanta, Gaviscon, Tums.
Interaction: Antacids can decrease the absorption of gabapentin, reducing its effectiveness if taken too closely together.
Advice: Take gabapentin at least 2 hours before or after antacids to prevent reduced absorption.

3. Opioids

Examples: Hydrocodone, morphine, oxycodone, tramadol.
Interaction: Combining gabapentin with opioids can lead to enhanced CNS depression, increasing the risk of drowsiness, confusion, respiratory depression, and overdose.
Advice: Use gabapentin and opioids together only under strict medical supervision. Your doctor may adjust the dosage or monitor you closely for signs of respiratory distress.

4. Muscle Relaxants

Examples: Cyclobenzaprine, baclofen, tizanidine.
Interaction: The combination can amplify drowsiness and dizziness, increasing the risk of falls and accidents.
Advice: If taking muscle relaxants with gabapentin, avoid activities that require full alertness until you know how they affect you together.

5. Other Anti-Seizure Medications

Examples: Carbamazepine, valproate, lamotrigine, topiramate.
Interaction: Gabapentin can interact with other anti-seizure medications, potentially leading to changes in blood levels, increased side effects, or reduced effectiveness of either drug.
Advice: Your doctor may need to monitor blood levels of certain anti-seizure medications and adjust dosages accordingly.

6. Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)

Examples: Ibuprofen, naproxen.
Interaction: NSAIDs can increase the risk of side effects like swelling (edema) when used with gabapentin.
Advice: Use NSAIDs with caution, especially if you have a history of kidney problems or fluid retention. Monitor for any unusual swelling.

7. Medications that Affect the Kidneys

Examples: Diuretics (e.g., furosemide), certain antibiotics (e.g., aminoglycosides), ACE inhibitors (e.g., lisinopril).
Interaction: Since gabapentin is excreted through the kidneys, combining it with other kidney-impacting drugs can lead to altered drug levels, either increasing side effects or reducing effectiveness.
Advice: If you have kidney disease or are on medications that affect the kidneys, your doctor may need to adjust the gabapentin dosage.

8. Certain Herbal Supplements

Examples: St. John’s Wort, valerian root, kava.
Interaction: These supplements may increase drowsiness and dizziness when taken with gabapentin.
Advice: Discuss any herbal supplements you are using with your doctor before starting gabapentin.

9. Oral Contraceptives

Examples: Birth control pills.
Interaction: While there is no direct interaction, some reports suggest gabapentin may reduce the effectiveness of oral contraceptives, though this is not well-established.
Advice: If you’re on birth control, discuss with your healthcare provider to ensure adequate contraceptive measures are in place.

10. Certain Antidepressants

Examples: Tricyclic antidepressants (e.g., amitriptyline), SSRIs (e.g., sertraline, fluoxetine), SNRIs (e.g., duloxetine, venlafaxine).
Interaction: Using gabapentin with antidepressants can increase the risk of drowsiness and dizziness. There may also be additive effects in managing pain or anxiety.
Advice: Monitor for any unusual side effects, especially when starting or changing dosages of either medication.

11. Blood Pressure Medications

Examples: ACE inhibitors, beta-blockers (e.g., atenolol, metoprolol).
Interaction: Gabapentin can potentially increase the sedative effect of these medications, leading to increased dizziness or fainting.
Advice: Monitor blood pressure regularly and report any unusual symptoms to your doctor.

12. Diabetes Medications

Examples: Insulin, metformin, glipizide.
Interaction: Gabapentin may cause fluctuations in blood sugar levels, which could interfere with diabetes management.
Advice: Monitor blood glucose levels regularly if you have diabetes and adjust medications with your doctor’s guidance if needed.

How to Manage Gabapentin Interactions

Inform Your Doctor: Always inform your healthcare provider about all the medications, supplements, and herbal remedies you are currently taking.
Monitor Side Effects: Keep track of any unusual symptoms, especially when starting a new medication or supplement alongside gabapentin.
Take at the Right Time: Follow guidelines about when to take gabapentin relative to other medications, particularly antacids.
Do Not Stop Suddenly: Never stop gabapentin or any interacting medication suddenly without consulting your doctor, as this can cause withdrawal symptoms or other health issues.