Haloperidol and Phenobarbital interaction
Haloperidol and Phenobarbital: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Haloperidol (Haldol Decanoate) label · effective 2025-11-11
Seizures: HALDOL DECANOATE is generally not recommended in patients receiving antiseizure drugs or who have a history of seizures or EEG abnormalities.
HALDOL DECANOATE is generally not recommended in patients receiving antiseizure drugs or have a history of seizures or EEG abnormalities.
Prevention or Management Avoid concomitant use of HALDOL DECANOATE with CNS depressants such as anesthetics, opioids, and alcohol.
CNS Depressants Clinical Impact Haloperidol may potentiate CNS depressants.
CYP3A4 Inducers Clinical Impact CYP3A4 inducers decrease haloperidol exposure (haloperidol is a CYP3A4 substrate) [see Clinical Pharmacology (12.3) ].
From the Phenobarbital (SEZABY) label · effective 2025-12-23
CNS depressants: Closely monitor for sedation and respiratory depression.
Drugs that Prolong the QT Interval : Avoid concomitant use.
CNS Depressants Closely monitor for signs of sedation and respiratory depression with concomitant use of SEZABY with other CNS depressants, including opioids [see Warnings and Precautions (5.1)] .
QT Prolongation SEZABY may prolong the QT interval [see Clinical Pharmacology (12.2)] .
Drugs that Prolong QT Interval SEZABY may prolong the QT interval [see Warnings and Precautions (5.10) and Clinical Pharmacology (12.2)] .
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.