MAJOR — Use With Caution
Phenibut and Gabapentinoids — CONTRAINDICATED (Additive CNS Depression)
Evidence level: MODERATE
DANGEROUS COMBINATION. Phenibut is chemically similar to gabapentin/pregabalin. Combining them is essentially doubling down on the same type of brain depressant, which can cause extreme sedation, breathing problems, and overdose.
Phenibut is structurally related to gabapentin and pregabalin (all are GABA analogues). They share overlapping mechanisms at voltage-gated calcium channels and GABA receptors. Combined use produces dangerous additive CNS depression, respiratory depression, and profound sedation. Cross-tolerance exists but does not ensure safety.
Do not combine phenibut with gabapentin or pregabalin. These are chemically related substances that amplify each other's sedative effects dangerously. Inform your prescriber if you use phenibut.
Take Pregabalin as prescribed. Phenibut can typically be taken with a meal, spaced 1-2 hours from the medication for clean absorption. Discuss this combination with your pharmacist for personalized guidance.
Higher risk for: those on multiple antiepileptics (enzyme induction/inhibition), liver impairment, elderly, pregnant individuals (teratogenicity concerns), or those with recent dose changes.
Extreme drowsiness, dizziness, impaired coordination, slowed breathing, confusion, loss of consciousness.
Disclose phenibut use. Discuss that phenibut is a gabapentinoid analogue not regulated by the FDA. Medical supervision needed for discontinuation of either substance.
Antiepileptic drug levels are sensitive to enzyme inducers and inhibitors. Discuss any changes with your neurologist before adding new substances. Safer supplement options: magnesium, omega-3s, and B vitamins are generally well-tolerated alongside seizure medications.
DANGEROUS COMBINATION. Phenibut is chemically similar to gabapentin/pregabalin. Combining them is essentially doubling down on the same type of brain depressant, which can cause extreme sedation, breathing problems, and overdose.
Take Pregabalin as prescribed. Phenibut can typically be taken with a meal, spaced 1-2 hours from the medication for clean absorption. Discuss this combination with your pharmacist for personalized guidance.
Extreme drowsiness, dizziness, impaired coordination, slowed breathing, confusion, loss of consciousness.
Antiepileptic drug levels are sensitive to enzyme inducers and inhibitors. Discuss any changes with your neurologist before adding new substances. Safer supplement options: magnesium, omega-3s, and B vitamins are generally well-tolerated alongside seizure medications.
Disclose phenibut use. Discuss that phenibut is a gabapentinoid analogue not regulated by the FDA. Medical supervision needed for discontinuation of either substance.
Or browse the full interaction database (121,000+ pairs).