Diphenhydramine and Gabapentin interaction
Diphenhydramine and Gabapentin: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Diphenhydramine label · effective 2026-03-05
Drug Interactions Diphenhydramine hydrochloride has additive effects with alcohol and other CNS depressants (hypnotics, sedatives, tranquilizers, etc).
From the Gabapentin (Neurontin) label · effective 2026-05-12
When the decision is made to co-prescribe NEURONTIN with another CNS depressant, particularly an opioid, or to prescribe NEURONTIN to patients with underlying respiratory impairment, monitor patients for symptoms of respiratory depression and sedation, and consider initiating NEURONTIN at a low dose.
Patients should be carefully observed for signs of central nervous system (CNS) depression, such as somnolence and sedation, when NEURONTIN is used with other drugs with sedative properties because of potential synergy.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.