Ensitrelvir: uses, dosing, side effects & brands
Ensitrelvir is a medicine sold in the U.S. under one brand. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
Key facts
- Available as
- Tablet
- Sold as
- Xocova
- Prescription?
- Prescription only
- Generic available?
- Not in our catalog
How ensitrelvir is dosed
From the FDA label for Xocova (application NDA220442). Other ensitrelvir products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
Verify pregnancy status of females of reproductive potential prior to initiating XOCOVA. ( 2.1 ) Begin XOCOVA as soon as possible and within 72 hours following contact with an individual who has COVID-19. ( 2.2 ) Dosage: 375 mg (three 125-mg tablets taken at the same time) orally on Day 1 and 125 mg (one 125-mg tablet) orally on Days 2 to 5 taken with or without food. ( 2.2 ) 2.1 Pregnancy Evaluation Prior to Initiating XOCOVA Verify pregnancy status of females of reproductive potential prior to initiating XOCOVA [see Warnings and Precautions (5.1) and Use in Specific Populations (8.1 , 8.3) ] . 2.2 Recommended Dosage The recommended dosage of XOCOVA in adults and adolescents 12 years of age and older is 375 mg (three 125-mg tablets taken together) orally on Day 1 and 125 mg (one 125-mg tablet) orally on Days 2 to 5 with or without food [see Clinical Pharmacology (12.3) ] . Begin XOCOVA as soon as possible and within 72 hours following contact with an individual who has COVID-19. The tablets should be taken at approximately the same time each day. If a dose of XOCOVA is missed, take the missed dose as soon as possible on the same day, and then take the next dose as scheduled the following day.
Ensitrelvir side effects
The following clinically significant adverse reactions are described elsewhere in the labeling: Hypersensitivity reactions including anaphylaxis [see Warnings and Precautions (5.3) ] The most common adverse events (regardless of causality) occurring in ≥1% of the XOCOVA group and at a greater frequency compared to placebo were headache, diarrhea, and cough. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Shionogi Inc. at 1-800-849-9707 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The overall safety profile of XOCOVA is based on data from 2,831 adults and adolescents exposed to the recommended dosage and duration of XOCOVA in controlled clinical trials. Trial SCORPIO-PEP was a randomized, double-blind, placebo-controlled trial in which 1,190 subjects received oral XOCOVA (375 mg [Day 1]/125 mg [Days 2-5]) and 1,187 subjects received oral placebo (Days 1-5). The most common adverse events (regardless of causality) occurring in ≥1% of the XOCOVA group and at a greater frequency compared to placebo were headache (2.9% and 2.6%, respectively), diarrhea (1.7% and 1.3%,…
Who shouldn’t take ensitrelvir
XOCOVA is contraindicated in patients with a history of clinically significant hypersensitivity reactions to ensitrelvir or any other components of the product. XOCOVA is contraindicated in patients taking drugs that are: Primarily metabolized by CYP3A for which elevated concentrations may be associated with serious and/or life-threatening reactions [see Drug Interactions (7.3) ] and Strong CYP3A inducers because they may significantly reduce ensitrelvir plasma concentrations, leading to the potential loss of virologic response [see Drug Interactions (7.3) ] . History of clinically significant hypersensitivity reactions to ensitrelvir or any other components of the product. ( 4 ) Co-administration with drugs primarily metabolized by CYP3A for which elevated concentrations may be associated with serious and/or life-threatening reactions. ( 4 , 7.3 ) Co-administration with strong CYP3A inducers considered to significantly reduce ensitrelvir plasma concentrations and may be associated with the potential for loss of virologic response. ( 4 , 7.3 )
Ensitrelvir drug interactions
Co-administration of XOCOVA can alter the plasma concentrations of other drugs, and other drugs may alter the plasma concentrations of XOCOVA. Consider the potential for drug interactions prior to and during XOCOVA use and review concomitant medications during XOCOVA use. ( 4 , 5.2 , 7 , 12.3 ) 7.1 Potential for XOCOVA to Affect Other Drugs Ensitrelvir is a strong inhibitor of CYP3A and an inhibitor of P-gp and BCRP. Co-administration of XOCOVA with drugs that are primarily metabolized by CYP3A or are transported by P-gp or BCRP may result in increased plasma concentrations of such drugs and increase the risk of adverse events [see Contraindications (4) , Warnings and Precautions (5.2) , Drug Interactions (7.3) , and Clinical Pharmacology (12.3) ] . For drugs that are CYP3A substrates and contraindicated with XOCOVA, initiation of XOCOVA should be considered only after careful evaluation of relevant clinical and pharmacokinetic factors related to the concomitant medication. In addition, re-initiation of contraindicated CYP3A substrates should be considered based on an assessment of the duration of CYP3A inhibition and patient‑specific considerations. Refer to individual drug prescribing information for additional information. 7.2 Potential for Other Drugs to Affect XOCOVA Ensitrelvir is a CYP3A substrate; therefore, drugs that induce CYP3A may decrease ensitrelvir plasma concentrations and reduce XOCOVA therapeutic effect [see Drug Interactions (7.3) and Clinical Pharmacology (12.3) ] . Therefore, use of XOCOVA with strong CYP3A4 inducers is contraindicated [see Contraindications (4) ] . No dose adjustment is recommended when XOCOVA is used concomitantly with moderate or weak CYP3A inducers [see Warnings and Precautions (5.2) ] . Refer to individual drug prescribing information for additional information. 7.3 Established and Other Potentially Significant Drug Interactions Table 1 provides examples of drugs that are contraindicated with XOCOVA [see Contraindications (4) and Warnings and Precautions (5.2) ] . Table 1 is provided as a guide and is not a comprehensive list of all possible drugs that may interact with XOCOVA. The healthcare provider should consult other appropriate resources, such as the prescribing information for the interacting drug, for comprehensive information on dosing and monitoring with concomitant use of a strong CYP3A inhibitor, like XOCOVA [see Drug Interactions (7.1) ]. Table 1 Drugs Contraindicated with XOCOVA due to Risk of Potentially Serious or Fatal Interaction [see Contraindications (4) ] Drug Class Drug(s) within Class Effect on Drug Concentration Clinical Comment Antiarrhythmics quinidine ↑ antiarrhythmic Co-administration is contraindicated due to potential for cardiac arrhythmias. Anticancer drugs apalutamide, enzalutamide ↓ ensitrelvir Co-administration is contraindicated due to potential loss of virologic response. Anticonvulsants carbamazepine See Clinical Pharmacology (12.3) , phenytoin ↓ ensitrelvir Co-administration is contraindicated due to potential loss of virologic response. Antigout agents colchicine ↑ colchicine Co-administration is contraindicated due to potential for serious and/or life-threatening reactions in patients with renal and/or hepatic impairment. Antimycobacterials rifampin ↓ ensitrelvir Co-administration is contraindicated due to potential loss of virologic response. Antipsychotics lurasidone, pimozide ↑ lurasidone, pimozide Co-administration is contraindicated due to serious and/or life-threatening reactions, such as cardiac arrhythmias. Cardiovascular drugs eplerenone, ivabradine ↑ eplerenone, ivabradine Co-administration is contraindicated. Cystic fibrosis transmembrane conductance regulator potentiators lumacaftor/ivacaftor ↓ ensitrelvir Co-administration is contraindicated due to potential loss of virologic response. Ergot derivatives dihydroergotamine, ergotamine, methylergonovine ↑ dihydroergotamine, ergotamine, methylergonovine Co-administration is contraindicated due to potential for acute ergot toxicity characterized by vasospasm and ischemia of the extremities and other tissues, including the central nervous system. Herbal products (for depression) St. John's wort ↓ ensitrelvir Co-administration is contraindicated due to potential loss of virologic response. HMG-CoA reductase inhibitors (statins) simvastatin ↑ simvastatin Co-administration is contraindicated. Discontinue use of simvastatin at least 12 hours prior to initiation of XOCOVA. Immunosuppressants voclosporin ↑ voclosporin Co-administration is contraindicated due to potential for acute and/or chronic nephrotoxicity. Microsomal triglyceride transfer protein (MTTP) inhibitors lomitapide ↑ lomitapide Co-administration is contraindicated due to potential for hepatotoxicity and gastrointestinal adverse reactions. Mineralocorticoid receptor antagonists finerenone ↑ finerenone Co-administration is contraindicated due to potential for serious adverse reactions, including hyperkalemia, hypotension, and hyponatremia. Sedatives triazolam ↑ triazolam Co-administration is contraindicated.
Every ensitrelvir product we track (1)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
Only one: Xocova.
What people report to the FDA about ensitrelvir
The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 33 reports naming ensitrelvir, and the FDA flagged 67% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:
- covid-199 reports
- coronavirus infection4 reports
- drug half-life increased4 reports
- immunosuppressant drug level increased4 reports
- covid-19 pneumonia3 reports
- drug clearance decreased3 reports
- immune-mediated hypothyroidism3 reports
- malaise3 reports
Read these as a signal, not a rate. A report does not mean ensitrelvir caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label section above.
Source: openFDA drug/event (FAERS), retrieved July 30, 2026.
Related calculators
Frequently asked questions
What is ensitrelvir?
XOCOVA tablets contain ensitrelvir, a SARS-CoV-2 main protease (M pro ) inhibitor.
Can you take ensitrelvir with other medicines?
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run ensitrelvir against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What forms does ensitrelvir come in?
Across the brands we track, ensitrelvir is currently marketed as tablet, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Is there a generic ensitrelvir?
We do not currently list a generic-labelled ensitrelvir product. That does not always mean none exists — it means none appears under a generic name in the FDA data we track. Ask your pharmacist.
Cite this page
- APA
- pharmaranks. (2026, July 24). Ensitrelvir: uses, dosing, side effects & brands. https://pharmaranks.com/drugs/ensitrelvir
- MLA
- “Ensitrelvir: uses, dosing, side effects & brands.” pharmaranks, 24 July 2026, https://pharmaranks.com/drugs/ensitrelvir.
We summarise public FDA and NIH sources — for a clinical claim, cite the primary source we link to as well.
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Read the full FDA label for ensitrelvir on DailyMed (NIH) ↗.