Naltrexone and bupropion and Tetrabenazine interaction
Naltrexone and bupropion and Tetrabenazine: 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 Naltrexone and bupropion (Contrave Extended-Release) label · effective 2025-11-10
…malformation, central nervous system tumor or infection, or metabolic disorders (e.g., hypoglycemia, hyponatremia, severe hepatic impairment, and hypoxia) excessive use of alcohol or sedatives, addiction to cocaine or stimulants, or withdrawal from sedatives patients with diabetes treated with insulin and/or oral diabetic medications (sulfonylureas and meglitinides)…
From the Tetrabenazine label · effective 2019-11-29
• Do not exceed 50 mg/day and the maximum single dose should not exceed 25 mg if administered in conjunction with a strong CYP2D6 inhibitor (e.g., fluoxetine, paroxetine).
Strong CYP2D6 inhibitors (e.g., paroxetine, fluoxetine, quinidine) markedly increase exposure to these metabolites.
A reduction in tetrabenazine tablets dose may be necessary when adding a strong CYP2D6 inhibitor (e.g., fluoxetine, paroxetine, quinidine) in patients maintained on a stable dose of tetrabenazine tablets.
The daily dose of tetrabenazine should not exceed 50 mg/day and the maximum single dose of tetrabenazine tablets should not exceed 25 mg in patients taking strong CYP2D6 inhibitors [see Dosage and Administration (2.3) , Warnings and Precautions (5.3) , Use in Specific Populations ( 8.7 ), Clinical Pharmacology (12.3) ].
Strong CYP2D6 Inhibitors In vitro studies indicate that α-HTBZ and β-HTBZ are substrates for CYP2D6.
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.