Wegovy and Gabapentin Interaction: What Patients and Prescribers Need to Know

Is there a pharmacokinetic interaction between Wegovy and gabapentin?

Wegovy is a GLP-1 receptor agonist. Semaglutide is broken down by proteolytic cleavage of its peptide backbone and beta-oxidation of its fatty acid side chain, not by CYP enzymes, and about 3% of a dose is excreted unchanged in urine [1]. Gabapentin is not appreciably metabolized, did not meaningfully inhibit the major CYP enzymes in the label's in vitro studies, and is eliminated unchanged by the kidneys.

The Wegovy label's drug interactions section covers insulin and insulin secretagogues, and oral medicines in general because semaglutide delays gastric emptying. It does not list gabapentin [1].

What is the real concern: dizziness and sedation?

Wegovy's label lists dizziness in 8% of adults on the 2.4 mg injection versus 4% on placebo in pooled weight-management trials [1]. The Neurontin label lists somnolence and dizziness as warnings; in postherpetic neuralgia trials (up to 3600 mg a day), somnolence occurred in 21% versus 5% on placebo and dizziness in 28% versus 8%.

FDA's 2019 communication on gabapentinoids lists symptoms that should prompt immediate medical attention: confusion, unusual dizziness or lightheadedness, extreme sleepiness, slowed or shallow breathing, unresponsiveness, and bluish skin [2]. FDA says the breathing risk applies to people taking gabapentin who also use opioids or other CNS depressants, who have lung conditions such as COPD, or who are older [2]. The communication does not mention semaglutide.

Does Wegovy's effect on gastric emptying change gabapentin absorption?

Wegovy's label says semaglutide delays gastric emptying and may affect absorption of oral medicines, and advises increased clinical or laboratory monitoring for oral drugs with a narrow therapeutic index or that require clinical monitoring [1]. It also reports that in clinical pharmacology trials with semaglutide 1 mg once weekly injection, semaglutide did not affect the absorption of orally administered medications [1]. Gabapentin is not named in that section, and the label reports no absorption result for it [1].

Kidney function: a separate issue

Wegovy's label warns about acute kidney injury due to volume depletion and says to monitor renal function in patients reporting adverse reactions that could lead to volume depletion [1]. In the Wegovy trials, acute kidney injury occurred in 0.4 versus 0.2 cases per 100 patient-years (7 versus 4 adults), more often in patients with prior renal impairment and during dose titration, often after gastrointestinal fluid loss [1].

Gabapentin clearance is proportional to creatinine clearance, and the Neurontin label sets lower maximum daily doses as creatinine clearance falls (for example 200 to 700 mg a day at a clearance above 15 to 29 mL/min). This is not a direct drug-drug interaction, but kidney function is relevant to gabapentin dosing during any illness that affects the kidneys.

What FDA says about gabapentin and breathing

The 2019 communication advises starting gabapentinoids at the lowest dose and monitoring for respiratory depression and sedation when they are co-prescribed with an opioid or another CNS depressant such as a benzodiazepine [2]. The Neurontin label's respiratory depression warning (section 5.8) applies to CNS depressants including opioids and to people with underlying respiratory impairment.