Nirmatrelvir and ritonavir and Norethindrone and ethinyl estradiol interaction
Nirmatrelvir and ritonavir and Norethindrone and ethinyl estradiol: 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 Norethindrone and ethinyl estradiol (Lo Loestrin Fe) label · effective 2025-03-07
…(5.2) ] Liver tumors, benign or malignant, or liver disease [see Warnings and Precautions (5.3) ] Undiagnosed abnormal uterine bleeding [see Warnings and Precautions (5.9) ] Use of Hepatitis C drug combinations containing ombitasvir/paritaprevir/ritonavir, with or without dasabuvir, due to the potential for ALT elevations [see Warnings and Precautions (5.4) ] .
Co-administration with Hepatitis C drug combinations containing ombitasvir/paritaprevir/ritonavir, with or without dasabuvir ( 4 )
Concomitant Use with HCV Combination Therapy – Liver Enzyme Elevation Do not co-administer Lo Loestrin Fe with HCV drug combinations containing ombitasvir/ paritaprevir/ritonavir, with or without dasabuvir, due to potential for ALT elevations [see Warnings and Precautions (5.4) ] .
Risk of Liver Enzyme Elevations with Concomitant Hepatitis C Treatment During clinical trials with the Hepatitis C combination drug regimen that contains ombitasvir/paritaprevir/ritonavir, with or without dasabuvir, ALT elevations greater than 5 times the upper limit of normal (ULN), including some cases greater than 20 times the ULN, were significantly more…
CYP3A4 inhibitors such as itraconazole or ketoconazole may increase plasma hormone levels.
From the Nirmatrelvir and ritonavir (Paxlovid) label · effective 2026-02-19
Hormonal contraceptive ethinyl estradiol ↓ ethinyl estradiol An additional, non-hormonal method of contraception should be considered during the 5 days of PAXLOVID treatment and until one menstrual cycle after stopping PAXLOVID.
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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.