Iloperidone and Promethazine and codeine interaction
Iloperidone and Promethazine and codeine: 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 Iloperidone (FANAPT) label · effective 2026-05-06
Avoid the use of FANAPT in combination with any other drugs that prolong the QT interval [see Warnings and Precautions (5.3) ] .
…prolong QTc including Class 1A (e.g., quinidine, procainamide) or Class III (e.g., amiodarone, sotalol) antiarrhythmic medications, antipsychotic medications (e.g., chlorpromazine, thioridazine), antibiotics (e.g., gatifloxacin, moxifloxacin), or any other class of medications known to prolong the QTc interval (e.g., pentamidine, levomethadyl acetate, methadone).
Strenuous exercise, exposure to extreme heat, dehydration, and anticholinergic medications may contribute to an elevation in core body temperature; use FANAPT with caution in patients who may experience these conditions.
From the Promethazine and codeine (Promethazine Hydrochloride and Codeine Phosphate) label · effective 2025-12-18
…PROMETHAZINE AND RESPIRATORY DEPRESSION IN CHILDREN; MEDICATION ERRORS; INTERACTIONS WITH DRUGS AFFECTING CYTOCHROME P450 ISOENZYMES; CONCOMITANT USE WITH BENZODIAZEPINES OR OTHER CNS DEPRESSANTS; NEONATAL OPIOID WITHDRAWAL SYNDROME Addiction, Abuse, and Misuse Promethazine HCl and Codeine Phosphate Oral Solution exposes patients and other users to the risks…
Risks from Concomitant Use with Benzodiazepines or Other CNS Depressants Concomitant use of opioids with benzodiazepines or other central nervous system (CNS) depressants, including alcohol, may result in profound sedation, respiratory depression, coma, and death.
Avoid the use of Promethazine HCl and Codeine Phosphate Oral Solution in patients taking benzodiazepines, other CNS depressants, or alcohol [ see Warnings and Precautions (5.10) , Drug Interactions (7.4) ].
( 5.9 , 7.1 , 7.2 , 7.3 ) Concomitant use of opioids with benzodiazepines or other central nervous system (CNS) depressants, including alcohol, may result in profound sedation, respiratory depression, coma, and death.
Avoid concurrent use of Promethazine HCl and Codeine Phosphate Oral Solution with alcohol or other central nervous system depressants because additional impairment of central nervous system performance may occur [ see Warnings and Precautions (5.10) ].
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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.