Gabapentin and Pregabalin Weight Gain: What the Labels Show, and Where a GLP-1 Fits

Pregabalin (Lyrica) causes weight gain often enough that its label gives it a warning section of its own: in trials of up to 14 weeks, 9% of people on it gained 7% or more of their body weight, against 2% on placebo, and the gain rose with dose and with time on the drug.^[2] Gabapentin (Neurontin) carries a smaller signal in its trials, about 2% to 3% reporting weight gain against 0% to 2% on placebo,^[1] though a pooled analysis of randomized trials put its average at 2.2 kg.^[5] Neither drug should be stopped suddenly. No trial has tested a GLP‑1 in people who gained weight on either one; the closest evidence is a single 2026 cohort.

The short answer, drug by drug

The table comes from separate trials in different conditions at different doses, so it is not a head-to-head comparison.^[1][4][2][3] The pattern is still plain: pregabalin’s numbers are several times gabapentin’s, and pregabalin’s climb steeply at the top doses.

Gabapentin: a small signal in the label, a larger one over time

Neurontin is approved for nerve pain after shingles (postherpetic neuralgia) and as an add-on treatment for partial seizures, though it is widely prescribed for other kinds of pain.^[1] In its shingles-pain trials, 2% of people on gabapentin reported weight gain against none on placebo. In the adult epilepsy trials the figures were 3% and 2%, and in children aged 3 to 12 they were 3% and 1%.^[1] The once-daily version, Gralise, reported 1.9% against 0.5%.^[4] Those trials were short, and they count weight gain only when someone reported it as a side effect.

Measured weight tells a bigger story. A 2015 Mayo Clinic meta-analysis of 257 placebo-controlled trials of commonly prescribed drugs linked gabapentin to an average gain of 2.2 kg, about 4.9 pounds. That put it alongside olanzapine (2.4 kg) and above mirtazapine (1.5 kg).^[5]

The longest look is old and small. A 1997 review followed 44 people with epilepsy on gabapentin for a year or more, most of them on high doses above 3,000 mg a day. Ten gained more than 10% of their starting weight and 15 gained 5% to 10%; 16 did not change and three lost weight. The gain usually began in the second or third month and leveled off after six to nine months, even though the dose stayed the same.^[6] There was no placebo group, and the doses were higher than most people take for pain.

Pregabalin: weight gain that rises with the dose

LYRICA associated weight gain was related to dose and duration of exposure but did not appear to be associated with baseline BMI, gender, or age. Weight gain was not limited to patients with edema.

— Lyrica (pregabalin) prescribing information, section 5.8

Lyrica is approved for diabetic nerve pain, nerve pain after shingles, fibromyalgia, nerve pain after spinal cord injury, and as an add-on for partial seizures.^[2] Its trial tables report weight gain at each dose, and the dose effect is hard to miss.

The label adds two figures that matter to people with diabetes, who are among the largest groups taking pregabalin for nerve pain. In the short trials, people with diabetes on pregabalin gained an average of 1.6 kg against 0.3 kg on placebo, with individual changes running from a loss of 16 kg to a gain of 16 kg. In a group of 333 people with diabetes who stayed on it for at least two years, the average gain was 5.2 kg. Blood-sugar control, measured by HbA1c, did not appear to worsen.^[2] Very few people quit the trials over it: 0.3% withdrew because of weight gain.^[2]

The extended-release form, Lyrica CR, reported weight gain in 3.7% of people against 1% on placebo in its double-blind phase.^[3]

Who gains, and how much

Most people on pregabalin do not gain much. A pooled analysis of 3,187 people from 41 of the manufacturer’s studies, followed for up to a year at 150 to 600 mg a day, found that 81.8% stayed within 7% of their starting weight. About one in six gained 7% or more, and most of them crossed that line between the second and twelfth month rather than early on. Those who gained were lighter at the start, on average, than those who did not.^[7] A Pfizer modeling study put the typical long-run change for an 82 kg person on 300 mg a day at 2.5% of body weight, against 0.7% on placebo, while noting that some people on the drug stayed level or lost weight.^[8]

• Higher dose. Every Lyrica table rises with dose, and its label says the gain tracks dose and time on the drug.^[2]
• Longer use. The two-year diabetes group averaged 5.2 kg, more than three times the short-trial figure.^[2] The gabapentin review saw gain build for six to nine months before it leveled off.^[6]
• Pioglitazone. In Lyrica’s diabetic trials, weight gain was reported in 4% of people on pregabalin alone and 7.5% of those also on a thiazolidinedione such as pioglitazone; swelling rose from 8% to 19%. The label asks for caution with the pairing because both drugs can cause fluid retention.^[2]
• Duloxetine alongside. In a Veterans Affairs chart review of nerve-pain patients treated for more than a year, people on duloxetine alone lost 0.9 pounds, those on pregabalin alone gained 3.6 pounds, and those on both gained 8.5 pounds.^[9] It was a single-site, retrospective study.

The Lyrica label found no link between weight gain and starting BMI, sex or age,^[2] so being heavier to begin with does not, on that evidence, make someone more likely to gain.

Water or fat: what is known about the cause

Some of the extra weight is fluid. Both drugs cause swelling in the legs and feet, and pregabalin does so in proportion to dose: in its shingles-pain trials, peripheral edema reached 16% at 300 and 600 mg against 4% on placebo.^[2] In Japanese drug-safety reports, pregabalin was strongly linked to edema, the swelling typically appeared about two weeks after starting, and people starting at 150 mg a day or more were more likely to be prescribed a water pill afterward.^[10]

Fluid does not explain all of it. The Lyrica label states outright that weight gain was not limited to people with edema.^[2] Its tables also report increased appetite: 5% against 1% on placebo in both the epilepsy and fibromyalgia trials, reaching 6% to 7% at the top doses.^[2] Beyond that, no study has pinned down why these drugs add weight, and how much of the gain is fat rather than water has not been measured in the trials cited here.

What can be done: start with the prescriber, never with the bottle

Both labels are firm about stopping. Neurontin’s says antiepileptic drugs should not be stopped abruptly because seizures may become more frequent, and that the dose should be tapered over at least a week.^[1] Lyrica’s says the same and lists what people reported after stopping quickly: insomnia, nausea, headache, anxiety, heavy sweating and diarrhea.^[2] Both labels note postmarketing reports of withdrawal symptoms, including seizures, agitation and confusion, and of suicidal thoughts after the drug was stopped.^[1][2] That applies whether the drug is taken for seizures or for pain.

What is reasonable to raise at an appointment follows from the evidence above. Because the gain tracks dose, ask whether the current dose is still the lowest that controls the pain or seizures. Ask whether swelling is part of the picture, since fluid retention is handled differently from fat gain. If pioglitazone or duloxetine is also on the list, mention it; both appeared alongside more weight gain in the data above.^[2][9] And if the drug is not clearly helping, that is a conversation about whether it is still needed at all, with a taper plan if not.

Can a GLP-1 offset gabapentin or pregabalin weight gain?

No randomized trial has tested it. A PubMed search for semaglutide, tirzepatide, liraglutide or exenatide together with gabapentin or pregabalin turns up reviews, animal work and pharmacovigilance studies, but no trial in people who gained weight on a gabapentinoid.

The closest evidence is a 2026 cohort from the NIH All of Us database. Researchers matched 610 adults who had epilepsy, type 2 diabetes and obesity, half starting a GLP‑1 and half not. In the 224 who had a weight recorded at 12 months, GLP‑1 users had lost 5.73% more than non-users. Among those taking a seizure drug the authors classed as weight-gaining, the difference was 4.15% (150 people). Gabapentin dominated that class: across the matched cohort, 52.8% of the GLP‑1 starters were on gabapentin and 15.7% on pregabalin. Seizure control did not worsen.^[11]

The limits are real. The study was observational, it pooled gabapentin and pregabalin with valproate and carbamazepine, and it enrolled only people with epilepsy plus diabetes plus obesity. It mixed several GLP‑1 drugs, from exenatide to tirzepatide. It shows that a GLP‑1 still worked for people on these drugs. It does not show how much of a gabapentinoid gain it undoes.

Antipsychotics are the nearest drug-induced weight gain with randomized evidence. In a small Australian trial of 31 people on clozapine, semaglutide brought weight down 13.88% over 36 weeks against 0.42% on placebo,^[12] and a meta-analysis found liraglutide took off 4.70 kg in antipsychotic-related gain.^[13] Those results come from a different drug class with a different cause of weight gain, and they cannot be carried over directly. The full story is in GLP-1 drugs and antipsychotic weight gain; the antidepressant equivalent is covered in antidepressants and a GLP-1.

Taking gabapentin or Lyrica with Ozempic, Wegovy or Zepbound

Many people take both, especially people with diabetes who use pregabalin or gabapentin for nerve pain. The current Wegovy and Zepbound labels do not mention gabapentin or pregabalin,^[14][15] and the gabapentinoid labels do not mention GLP‑1 drugs. Both gabapentinoids leave the body almost entirely unchanged through the kidneys rather than through liver enzymes,^[1][2] so the usual chemical interactions are not expected. Wegovy’s label notes that the drug slows the stomach and could affect how oral medicines are absorbed, but that in its clinical pharmacology studies, semaglutide 1 mg did not affect absorption of the oral drugs tested.^[14] Neither drug was among them, and no study has measured gabapentin or pregabalin levels on a GLP‑1. The overlaps worth knowing are side effects that add up.

• Dizziness and falls. The gabapentinoids cause far more dizziness and sleepiness than the GLP‑1s do, and both labels warn against driving until you know how the drug affects you.^[1][2] A GLP‑1 adds its own dizziness, plus low blood pressure and, with insulin or a sulfonylurea, low blood sugar. More on that in GLP-1 dizziness and blood pressure pills.
• Constipation and the bowel. Lyrica’s label notes postmarketing reports of intestinal obstruction, paralytic ileus and constipation when it was taken with other constipating drugs such as opioids.^[2] The Wegovy and Zepbound labels list ileus, obstruction and severe constipation among their own postmarketing reports.^[14][15] No study has looked at the two together. Persistent constipation on both is worth raising early; see GLP-1 constipation: what works.
• Kidneys. Gabapentin and pregabalin doses are set by kidney function, because clearance falls as kidney function falls.^[1][2] The GLP‑1 labels warn of acute kidney injury, mostly in people dehydrated by vomiting or diarrhea.^[14][15] A bad stretch of stomach side effects is a reason to call the prescriber about the gabapentinoid dose too. Background in GLP-1 drugs and your kidneys.
• Breathing. Both gabapentinoid labels warn of serious, sometimes fatal, breathing suppression when they are combined with opioids or other sedating drugs, or used by people with lung disease.^[1][2] A GLP‑1 is not a sedative and is not named in those warnings. The warning matters if opioids, benzodiazepines or alcohol are also involved.

The wider list of drugs that need attention on a GLP‑1 is in GLP-1 drugs and your other medications.

What to ask the prescriber

1. Is this the lowest dose that works? Pregabalin’s weight gain is dose-related on its own label.
2. Is some of my gain swelling? Check the ankles and shins, and mention any rapid jump in weight.
3. If I come off it, what is the taper? Both labels require at least a week, and longer is common in practice.
4. Do my other medicines add to it? Pioglitazone, duloxetine, opioids, benzodiazepines and alcohol are the ones the evidence above flags.
5. If I start a GLP‑1, does anything change? Mention dizziness, constipation and any stomach upset that could dehydrate you.