Butalbital, aspirin, caffeine, and codeine and Efavirenz, lamivudine, and tenofovir interaction
Butalbital, aspirin, caffeine, and codeine and Efavirenz, lamivudine, and tenofovir: 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 Butalbital, aspirin, caffeine, and codeine (BUTALBITAL, ASPIRIN, CAFFEINE and CODEINE PHOSPHATE) label · effective 2026-01-15
The effects of concomitant use or discontinuation of cytochrome P450 3A4 inducers, 3A4 inhibitors, or 2D6 inhibitors with codeine are complex.
Use of cytochrome P450 3A4 inducers, 3A4 inhibitors, or 2D6 inhibitors with BUTALBITAL, ASPIRIN, CAFFEINE and CODEINE PHOSPHATE requires careful consideration of the effects on codeine, and the active metabolite, morphine.
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 codeine 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 with codeine are complex.
Cytochrome P450 3A4 Interaction The concomitant use of BUTALBITAL, ASPIRIN, CAFFEINE and CODEINE PHOSPHATE with all 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,…
From the Efavirenz, lamivudine, and tenofovir (SYMFI) label · effective 2019-10-15
Avoid SYMFI with concurrent or recent use of a nephrotoxic agent (e.g., high-dose or multiple non-steroidal anti-inflammatory drugs [NSAIDs]) [see Drug Interactions (7.3) ] .
Cases of acute renal failure after initiation of high-dose or multiple NSAIDs have been reported in HIV-infected patients with risk factors for renal dysfunction who appeared stable on TDF.
Alternatives to NSAIDs should be considered, if needed, in patients at risk for renal dysfunction.
Some examples include, but are not limited to, acyclovir, cidofovir, ganciclovir, valacyclovir, valganciclovir, aminoglycosides (e.g., gentamicin), and high-dose or multiple NSAIDs [see Warnings and Precautions (5.4) ] .
Narcotic analgesic: Methadone ↓ methadone Monitor for signs of methadone withdrawal and increase methadone dose if required to alleviate withdrawal symptoms.
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.