Gabapentin Interactions

Gabapentin Interactions: Introduction

Some of those with epilepsy know how the anticonvulsant medication gabapentin can successfully control seizures. Gabapentin decreases the excitability in the brain and controls partial onset seizures in adults and children over three years old. Epilepsy requires long-term therapy; meanwhile, additional health conditions may occur that require medical treatment. (1-2)

If you’re using gabapentin, you probably know the possible side effects but what about interactions? Have you read about it? It doesn’t look like an exciting reading; however, particular drugs may negatively affect gabapentin.

If you have heartburn, you would like to get rid of the burning pain in your chest immediately. However, before you take the antacid, you should check if it contains magnesium. Taking magnesium with gabapentin will decrease the therapeutic effect of gabapentin. (1)

There are other drug interactions of gabapentin that you should also know. Keep reading this article that explains what you need to understand about interactions and which of them need to be cautious.

Drug interactions may affect either drugs’ availability, elimination, or other pharmacokinetic characteristics and cause negative results consequently. For example, when naproxen, a nonsteroidal anti-inflammatory pain reliever, is co-administered with gabapentin, it increases the amount of absorbed gabapentin by 12% to 15%. Likewise, gabapentin does not affect naproxen pharmacokinetics. Or cimetidine, a gastric acid reducer for treating ulcers, alters the renal excretion of gabapentin, but the effect is small and has no clinical importance. (1)

Below, you can find more about gabapentin interactions with opioids, antacids, and alcohol.

Opioids

Opioids are medications that are used to relieve pain. Prescription opioids are oxycodone, hydrocodone, codeine, morphine, oxymorphone, fentanyl, and methadone, which doctors recommend for moderate to severe pain. Chronic headaches and backaches, pain during surgery recovery, severe pain in cancer patients, and pain caused by injuries during sports, falls, or car accidents can be successfully treated with opioids. Heroin belongs to the opioid group, yet, it is illegal and has a high potential for abuse. (3-4)

Opioids bind with opioid receptors on nerve cells and do not allow the message of the pain to be transmitted from the body to the brain. In this way, it decreases pain perception. (3)

Opioids have side effects such as sleepiness and nausea, as well as more severe shallow breathing, slowed heart rate, and loss of consciousness. The other negative side of opioids is being highly addictive, primarily if opioids are taken for a long time. (3)

Concomitant use of gabapentin with opioids or other CNS depressants may cause serious, life-threatening, or fatal respiratory depression, as addressed in the prescribing information. Respiratory depression can also happen when there is an underlying respiratory impairment. (1)

During 2012-17, several deaths from respiratory depression with gabapentinoids were found in reports submitted to Food and Drug Administration (FDA) when gabapentinoids were taken by patients with pre-existing respiratory risk factors. Based on these findings, in 2019 FDA issued a warning saying:

“… serious breathing difficulties may occur when gabapentin or pregabalin is taken with other medicines that depress the central nervous system (CNS) such as opioids, in those patients who have underlying respiratory problems, or in the elderly.” (5)

Respiratory problems can be severe and life-threatening; therefore, follow the FDA recommendation and, as stated in the report, pay attention if you notice any of the following symptoms:

“Confusion or disorientation;
Unusual dizziness or lightheadedness;
Extreme sleepiness;
Slowed, shallow, or difficult breathing;
Unresponsiveness, which means the person doesn’t answer or react normally or you can’t wake them up;
Bluish-colored or tinted skin, especially on the lips, fingers, and toes.” (5)

If you experience any of the above symptoms, ask for medical care immediately.

Due to the possible life-threatening and fatal outcomes of respiratory depression, if the doctor decides to prescribe gabapentin together with opioids, monitoring will be required. In such cases, one of the alternatives is to begin gabapentin therapy at a low dose. Depending on the response, dose reduction or drug withdrawal can be an option. (1)

Drugs Containing Aluminum Hydroxide and Magnesium Hydroxide

Antacids are medications that neutralize the acid in the stomach and are used for heartburn treatment. The acid moving from the stomach to the esophagus causes burning pain in the chest. It occurs after a meal, in the evening, or if you lie down.

Antacids contain magnesium, aluminum, or calcium salts as active ingredients and are prescription medications but can also be found as over-the-counter. Magnesium and aluminum hydroxides, when used with gabapentin, decrease the level of gabapentin in the body by 20%. This decrease impacts the clinical effect of gabapentin. (1, 6, 7, 8)

If you need to use antacids, or supplements containing magnesium and aluminum, make sure that there is at least 2 hours time interval when you take gabapentin after. By this, you will reduce the negative effect of antacids on gabapentin bioavailability to 10%. (1)

Gabapentin and Alcohol: Yes or No?

You might read that gabapentin can be used to treat alcohol use disorder (AUD). A randomized clinical trial from 2020 suggests that gabapentin might be the most efficacious medical treatment in people with AUD and those with a history of alcohol withdrawal symptoms. (9)

Gabapentin efficacy varies in different studies depending on its dosing and formulation. It is used off-label, thanks to the small but valuable positive effects in mild alcohol withdrawal, considering the significant morbidity due to AUD. However, gabapentin, as a single therapy for moderate to severe AUD, is not appropriate because of the risk of seizures and its potential for abuse. (10)

When used with alcohol, two laboratory studies didn’t find that gabapentin influenced the pharmacokinetics of alcohol or alcohol’s subjective effects. (10) However, the National Institute on Alcohol Abuse and Alcoholism suggests that the known side effects of gabapentin (drowsiness and dizziness) can occur as a reaction to alcohol. Therefore, avoid alcohol consumption while on gabapentin treatment. Consult your doctor to learn more about it. (11)

Gabapentin also affects urinary tract infection tests. It can cause false positive results. Therefore, inform healthcare professionals in the laboratory if you use gabapentin. (1)

Read the Medication Guide carefully and talk to your doctor about your concerns when using gabapentin.

What are Gabapentin Side Effects You Should Know?

Gabapentin may cause dizziness, somnolence, and peripheral edema in patients with postherpetic neuralgia. In the Medication Guide, you may find that patients with epilepsy also reported somnolence, dizziness, lack of coordination, fatigue, abnormal eye movements, viral infection, fever, nausea and/or vomiting, and hostility as the most common side effects. (1)

If you start using gabapentin, be careful about the ability to drive due to somnolence/sedation and dizziness. Gabapentin may cause allergic reactions. Use the medication as your doctor prescribed, and don’t stop taking it abruptly; it can increase the frequency of seizures. Be cautious about any changes in behavior, including suicidal thoughts or behavior. (1)

How is Gabapentin Used?

Gabapentin dosage depends on the indication and disease severity. In addition, some of the side effects and interactions are associated with gabapentin doses. Therefore, it is crucial to take it as recommended, either in tablets, capsules, or oral solution.

The initial dose in epilepsy is 900 mg three times daily, and the doctor may increase it step by step up to the maximal 1.800 mg/day. In younger patients aged 3 to 11 years, the doctor will define the dose according to the age and weight and should begin from 10 mg/kg/day to the maximal 40 mg/kg/day, three times daily.

In patients with postherpetic neuralgia, dosage begins with a single dose of 300 mg on the first day. On the second day, the dose can be increased to 600 mg daily, divided into two doses. On the third day, the daily dose of 900 mg should be divided into 3 single doses. The maximal daily dose can increase up to 1.800 mg.

Only for Restless Leg Syndrome treatment, the dose is 600 mg once daily, taken every day at the same time, and flat.

Make sure that you check if your doctor prescribed immediate or extended-release formulation. You should take the medication twice or three times daily, depending on the formulation. (1)

The bottom line

Gabapentin can help you when suffering from the pain of postherpetic neuralgia or put under control seizures in people with epilepsy. Use it as prescribed to avoid possible side effects.

Before using gabapentin, tell your doctor about your medications, including OTC and supplements. Your doctor will know best if there is a risk for drug interactions and what is the best therapeutic approach. Also, talk to your doctor if you drink alcohol or have any experience with drug abuse.

Tell your doctor if you experience any adverse event; your doctor will know if it is associated with gabapentin, the result of interaction, and so. If severe symptoms occur, such as slower or difficulties with breathing, swelling of the lips, throat, and tongue, worsened depression, suicidal behavior, or self-harm thoughts, inform your doctor immediately and ask for medical help.

You or your doctor may report adverse events to the FDA MedWatch Adverse Event Reporting program online (https://www.fda.gov/safety/medwatch-fda-safety-information-and-adverse-event-reporting-program) or by phone (1-800-332-1088).

Gabapentin is prescribed for you to help your disease. Learn about the medication you take and keep the treatment safe.

Grants for Medical

Gabapentin Interactions: Which Medications Require Monitoring While on Therapy?