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Gabapentin (Neurontin) And Weight Gain: What Studies Say

<p>Gabapentin (Neurontin) And Weight Gain: What Studies Say</p>
Dr. Constance Odom, MD Picture of Dr. Constance Odom, MD

Medically reviewed by

Written by our editorial team.

Last Edited 6 min read

The origins of Gabapentin can be dated back to the 1970s in Japan, where it was created and used as an anti-spasmodic—muscle relaxant. For years, it was used for this specific purpose until experts found that the tablet could successfully treat other conditions, such as epilepsy, nerve pain, shingles, and more, without posing severe risks to patients. 

The United States FDA approved these additional uses in 1993, which led to the tablet becoming world-famous. Its widespread use brought its beneficial effects to light along with some unwanted effects, such as weight gain. While weight gain can be a welcomed effect for some looking for a fuller aesthetic look, the gain is not kind to the body or our health. 

Below we look at Gabapentin in greater detail and find out what studies have to say about its link to weight gain:

What is Gabapentin and its Uses?

Gabapentin, commonly known by its brand name, Neurontin, is an anti-convulsant medication used primarily to manage partial seizures. The tablet uses the active ingredient, gabapentin, to carry out its function and comes in different doses and forms (immediate and extended release) to suit a wide range of users.

The tablet is a derivative of GABA, a chemical brain messenger that blocks impulses between nerve cells in the brain. It can effectively correct abnormalities that cause specific conditions by manipulating different brain processes. 

Some of the effects the tablet produces include:

  • Anti-seizure-The tablet's anti-seizure effects work by disabling nerve activity to reduce the intensity and occurrence of seizures.

  • Anxiolytic- Anxiolytic effects, also known as anti-anxiety effects, reduce unwarranted feelings of anxiousness from patients with conditions like social phobias.

  • Sedative and analgesic-The tablet is a structural analog of GABA. Thus, it can induce sedation and analgesia (pain relief) by affecting GABA receptors and neurotransmitters that control sleep and pain sensations.

Gabapentin's versatility doesn't stop there, as experts found it can also be used with polypharmacy, adjunctive and palliative care treatment plans. This demonstrates both its safety and tolerability. The multiple effects produced by Gabapentin means it is FDA-approved to treat/manage more than one condition. 

These conditions include:

  • All types of seizures- This condition causes sudden, uncontrolled electrical disturbances in the brain. It can lead to behavioral changes, movements or feelings, or loss in levels of consciousness. 

  • Pain after shingles (post-herpetic neuralgia)-A lasting pain in areas of the skin where shingles have occurred.

  • Restless leg syndrome (RLS)- This condition causes irrational leg movements triggered by uncomfortable sensations in the legs. 

In addition to these primary or intended uses, Gabapentin is also used off-label. Off-label means that the tablet was not specifically designed for this use, and it is often the last resort of treatment when recommended options are ill-advised or ineffective. 

Off-label uses are sometimes viewed as controversial, as sometimes there isn't enough clinical evidence backing a product's use to treat conditions it wasn't designed to manage. However, Gabapentin is different, as it has been extensively researched for both its intended and off-label uses. 

Let's look at some of the Gabapentin off-label uses below:

  • Migraines

  • Alcohol Withdrawal 

  • Restless leg syndrome

  • Menopausal symptoms

  • Sleep issues (insomnia) 

  • Benign essential tremors 

  • Anxiety or bipolar disorders

  • Uremic pruritus in liver failure

  • Periodic limb movement disorder, burning mouth syndrome

  • Specific  pain Relief- neuropathic pain or pain caused by damage to the somatosensory system, post-operative surgical pain

Although Gabapentin was not designed to treat this extensive list of conditions, its beneficial chemical structure has made it possible.

Gabapentin Side Effects

It's clear that Gabapentin is a force to be reckoned with in the medicine industry. It's been proven to be both versatile, potent, and safe, a trio of benefits that's hard to find in a treatment that falls under the gabapentinoid class. The issue of weight gain does slightly taint the image of perfection the treatment carries, but it isn't a flaw in composition. 

It's just an uncommon side effect that isn't always experienced. A PubMed study investigating the effect of Gabapentin on 44 patients found that 10 patients gained more than 10% of their original weight, 15 patients gained 5% more, 16 patients had no change, and 3 patients lost 10% of their original weight. 

This confirms that weight gain is not a persistent or consistent side effect that appears in all patients. Patients are more likely to experience common side effects such as:

  • Nausea, vomiting, or diarrhea

  • Swollen arms/legs or blurred vision

  • Dry mouth, sweating, mood changes

  • Dizziness, drowsiness, or double vision

These side effects are typically mild and aren't a reason to discontinue treatment use. It is merely the body's way of getting familiar with the effects of Gabapentin. Once the body is familiar with the treatment, the side effects gradually subside and completely disappear. Users can employ some home remedies to help reduce the intensity or duration of some of the symptoms.

Gabapentin and Weight Gain Explained

Gabapentin has been on the market for several decades now, and there have been reports of users gaining weight while using the treatment. This issue has, of course, sparked the interest of several experts in the medical research field. 

The first thing researchers looked at was the treatment's composition to see if any components in the formula may cause weight gain. If you look at the back of a Gabapentin box, you will notice that the treatment only has one active ingredient—gabapentin (the treatment's namesake) and inactive ingredients.

Inactive ingredients in the formula include: 

  • Lactose, corn-starch, talc, gelatine, titanium dioxide, FD&C Blue No. 2, yellow iron oxide, and red iron oxide

These inactive ingredients do not influence the medication's capabilities or effects. However, it does have some important purposes, such as:

  • Binding agents

  • Stabilizers for active ingredients 

  • Assistance in absorbing the medication 

  • Preservatives to ensure the medication lasts long

  • Coating for pills, capsules, and tablets for easy swallowing

None of these components are precursors of weight gain or can affect weight in any way. So composition is ruled out. The spotlight is then put on Gabapentin's effects. As we mentioned earlier, Gabapentin produces quite extensive and far-reaching effects, which all take place in the brain. 

According to a PubMed study, Gabapentin use can affect dopamine levels in some individuals resulting in overeating (side effect). The treatment can also stimulate appetites and serotonin levels in some individuals, which again causes overeating—weight gain. 

Gabapentine and Weight Gain Studies 

Several studies evaluated the link between Gabapentin use and weight gain. While some studies came up empty on findings, others presented solid results demonstrating the possible link between weight gain and Gabapentine use.

Let's look at some of them below:

  • PubMed study evaluating the appetite-stimulating effect of Gabapentin found that food intake increased after the administration of the treatment in all participants, showing that the treatment does stimulate appetites. However, the appetite-stimulating effect will not be the same across all users as some may eat significantly more, and others may increase their intake a little. 

  • PubMed study evaluating the effects of Gabapentin found that the treatment increases serotonin concentrations, which may be relevant to neurobehavioral actions. This means that Gabapentin can increase the impulse to eat in certain individuals. A study published in the Pharmacy Times also shows that alterations in brain serotonin can contribute to unhealthy eating patterns, overeating, and binge eating.

  • The Journal of Pain Research study found that Gabapentin affects the dopamine system. While this may seem irrelevant to weight gain, there actually is a link. A ScienceDaily study confirms that a slight disruption/unwarranted alteration to dopamine levels can cause snacking, overeating, and weight gain. 

The above confirms that Gabapentin can cause an increase in consumption/food intake, which causes weight gain. However, this will not occur in all users as each patient is prescribed the treatment for different reasons. In some users, Gabapentin's effect on dopamine, serotonin, or appetites might be warranted/needed. In these cases, weight gain may not occur or be unnoticeable.

How to Avoid Weight Gain on Gabapentin

Whether you want to avoid weight gain while taking Gabapentin or get rid of the extra pounds that you've gained after you've already commenced a Gabapentin treatment plan, there are some practical tips that can help. 

Let's look at some of them below:

  • Lower your dose 

In certain cases, it is possible to lower the dose of Gabapentin and still get adequate relief from your condition's symptoms. However, you cannot do this on your own, reduction of doses should be made with the help of your doctor.

  • Have smaller food portions 

Gabapentin affects certain hormones which stimulate appetite, making you feel more hungry. This may lead to eating more than usual. Without exercise and continued unhealthy eating habits, weight gain is inevitable. 

Studies show that limiting food portions or having smaller portions throughout the day can help you feel fuller and stop quick weight gain. You can also consult with a dietician about including high-fiber foods into your diet that will keep you fuller for longer, reducing the chance of overeating. 

  • Drink more water

Drinking enough water increases the number of calories you burn, known as resting energy expenditure. A study has shown that resting energy expenditure increased by 30% within 10 minutes of drinking water. 

Experts also claim that drinking at least 2 glasses of water before eating a meal reduces appetite, which leads to weight loss. One study showed that middle-aged, overweight individuals who drank water before meals lost 44% more weight than those who did not drink water. 

Another study concluded that drinking water before having breakfast reduced the number of calories eaten during the meal by 13%. 

  • Avoid refined sugars

Refined sugars such as high fructose corn syrup, honey, cane sugar, or syrup are added to various foods and drinks to make them taste sweeter. Almost all food and drinks on the market today contain refined sugar, making it difficult to manage how much we consume in a day. 

Consuming high volumes of food/drink items that contain refined sugar can lead to weight gain. This is because they are not nutritional and cannot keep you satisfied for long periods—leading to excessive eating. 

Studies show that excess sugar also causes a rise in blood sugar levels, leading to weight gain due to lowered insulin production. So, reducing your consumption of refined sugars can significantly reduce weight gain. 

An analysis of various studies concluded that there is enough evidence to prove that decreasing sugar in the diet can lead to a decrease in body weight. 

  • Exercise regularly

Gabapentin relaxes the central nervous system, which may make users tired. While it may be difficult to start, exercise and staying active can combat fatigue and contribute to weight loss

Cardio exercises like walking, cycling, running, and swimming are enjoyable activities that greatly help with weight loss and speed up your metabolism. A 10-month study showed that cardio exercise helped participants lose at least 5% of their body weight in each session. 

Other studies showed that cardio helped reduce harmful belly fat linked to type 2 diabetes and heart disease. Exercising regularly can also improve your mood, which increases motivation to stick to your routine. 

  • Avoid the consumption of alcohol

Mixing Gabapentin and alcohol is not advised as you may experience unwanted side effects such as nausea, dizziness, and impaired balance. Most alcoholic drinks also contain high amounts of carbohydrates and empty calories, which increase your appetite and blood sugar levels leading to weight gain. 

  • Include more protein in your diet 

A healthy amount of protein in your diet helps you shed fat, maintain fat loss, and allows you to stay fuller throughout the day. Protein increases metabolism, reduces appetite, and regulates hormones that significantly affect weight regulation. It also reduces ghrelin levels, a hormone that makes you feel hungry. 

Protein has a high thermic effect on the body, which refers to the number of calories taken to digest food. A high protein intake allows you to burn more calories around the clock, even during sleep. A study showed that protein boosted metabolism and burned about 80 to 100 calories daily. This contributes to weight loss.  

  • Try to get more sleep 

Various studies show that sleep-deprived individuals have an increased appetite due to the imbalance of hormones that control fullness and hunger. Experts have also found that lack of sleep increases the craving for high-calorie foods, fat, and carbohydrates. 

Therefore, getting a healthy amount of sleep (7 to 8 hours a night) will promote weight loss by reducing your appetite, making better food choices, and avoiding late-night snacking. A study shows that adequate sleep can be used to treat obesity as it promotes weight loss. 

Although these methods are quite effective and work for most individuals, remember that weight loss occurs differently in everyone. Depending on age, underlying conditions, metabolism rates, and the consumption of other medicines, weight loss may occur slower or faster. Nevertheless, integrating the above into your life can ensure that your Gabapentin journey is weight gain free. 



19 Sources

Nu Image Medical has strict sourcing guidelines to ensure our content is accurate and current. We rely on peer-reviewed studies, academic research institutions, and medical associations. We strive to use primary sources and refrain from using tertiary references. 

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your physician about the risks and benefits of any treatment. Nu Image Medical may not offer the medications or services mentioned in this article.