Efavirenz and Tramadol and acetaminophen interaction
Efavirenz and Tramadol and acetaminophen: 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 Tramadol and acetaminophen (Tramadol Hydrochloride and Acetaminophen) label · effective 2026-01-01
Interactions with Drugs Affecting Cytochrome P450 Isoenzymes The effects of concomitant use or discontinuation of cytochrome P450 3A4 inducers, 3A4 inhibitors, or 2D6 inhibitors with tramadol are complex.
Use of cytochrome P450 3A4 inducers, 3A4 inhibitors, or 2D6 inhibitors with tramadol hydrochloride and acetaminophen requires careful consideration of the effects on the parent drug, tramadol, and the active metabolite, M1 [see Warnings and Precautions (5.7) , Drug Interactions (7) ] .
The effects of concomitant use or discontinuation of cytochrome P450 3A4 inducers, 3A4 inhibitors, or 2D6 inhibitors with tramadol are complex.
Risks of Interactions with Drugs Affecting Cytochrome P450 Isoenzymes The effects of concomitant use or discontinuation of cytochrome P450 3A4 inducers, 3A4 inhibitors, or 2D6 inhibitors on levels of tramadol and M1 from tramadol hydrochloride and acetaminophen are complex.
Cytochrome P450 3A4 Interaction The concomitant use of tramadol hydrochloride and acetaminophen with cytochrome P450 3A4 inhibitors, such as macrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g., ketoconazole), and protease inhibitors (e.g., ritonavir) or discontinuation of a cytochrome P450 3A4 inducer such as rifampin, carbamazepine, and…
From the Efavirenz label · effective 2024-03-31
QT Prolonging Drugs There is limited information available on the potential for a pharmacodynamic interaction between efavirenz and drugs that prolong the QTc interval.
Narcotic analgesic: Methadone ↓ methadone * Monitor for signs of methadone withdrawal and increase methadone dose if required to alleviate withdrawal symptoms. * The interaction between efavirenz and the drug was evaluated in a clinical study.
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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.