Quick answers
- What is Doravirine, islatravir used for?
- The FDA-approved label (Idvynso, Merck Sharp & Dohme LLC, April 20, 2026) says: “IDVYNSO™ is indicated as a complete two-drug regimen for the treatment of human immunodeficiency virus type 1 (HIV-1) infection in adults to replace the current antiretroviral regimen in those who are virologically-suppressed (HIV-1 RNA less than 50 copies/mL) on a stable antiretroviral regimen with no history of virologic treatment failure and no known substitutions associated with resistance to doravirine […]. …” This page is not medical advice. Talk to your doctor or pharmacist before you start, stop or change any medicine.
- What are the side effects of Doravirine, islatravir?
- The “Adverse Reactions” section of the FDA label (Idvynso, Merck Sharp & Dohme LLC, April 20, 2026) begins: “The following serious adverse reactions are described in greater detail in other sections of the labeling: Skin and Hypersensitivity Reactions [see Warnings and Precautions (5.1)] Most common adverse reactions (incidence greater than or equal to 2%, all grades): diarrhea, dizziness, fatigue, abdominal distension, headache, and weight increased.” … This page is not medical advice. Talk to your doctor or pharmacist before you start, stop or change any medicine.
- What are the drug interactions of Doravirine, islatravir?
- The “Drug Interactions” section of the FDA label (Idvynso, Merck Sharp & Dohme LLC, April 20, 2026) begins: “Because IDVYNSO is a complete regimen, co-administration with other antiretroviral medications for treatment of HIV-1 infection is not recommended. (7.1) Consult the full prescribing information prior to and during treatment for important potential drug-drug interactions.” … This page is not medical advice. Talk to your doctor or pharmacist before you start, stop or change any medicine.
- Does Doravirine, islatravir have a boxed warning?
- No. None of the 1 FDA labels we found for this medicine has a boxed warning.
- Is there a shortage of Doravirine, islatravir?
- No current shortage is listed by the FDA for the products of this medicine (FDA data from October 30, 2026).
- Has Doravirine, islatravir been recalled?
- No recall linked to the products of this medicine appears in the FDA enforcement reports we use.
- Who makes Doravirine, islatravir?
- 1 company lists prescription products of Doravirine, islatravir in the FDA NDC Directory, including Merck Sharp & Dohme LLC.
What Doravirine, islatravir is used for
Quoted from the “Indications and Usage” section of the FDA-approved label.
IDVYNSO™ is indicated as a complete two-drug regimen for the treatment of human immunodeficiency virus type 1 (HIV-1) infection in adults to replace the current antiretroviral regimen in those who are virologically-suppressed (HIV-1 RNA less than 50 copies/mL) on a stable antiretroviral regimen with no history of virologic treatment failure and no known substitutions associated with resistance to doravirine […]. …
— FDA label: Idvynso, Merck Sharp & Dohme LLC, effective April 20, 2026. Read the full label on DailyMed →
Label quoted: the one for the most common form (tablet, film coated, oral), Idvynso, Merck Sharp & Dohme LLC; it covers 1 product in the FDA NDC Directory. The side effects, interactions, dosage and pregnancy quotes below come from this same label.
This page is not medical advice. Talk to your doctor or pharmacist before you start, stop or change any medicine.
Boxed warning
A boxed warning (“black box”) is the FDA’s strongest warning on a drug label, for serious or life-threatening risks.
The label quoted above has no boxed warning.
Doravirine, islatravir side effects
Quoted from the “Adverse Reactions” section of the FDA-approved label. Tell your doctor about any side effect that worries you.
The following serious adverse reactions are described in greater detail in other sections of the labeling: Skin and Hypersensitivity Reactions [see Warnings and Precautions (5.1)] Most common adverse reactions (incidence greater than or equal to 2%, all grades): diarrhea, dizziness, fatigue, abdominal distension, headache, and weight increased.
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(6.1) To report SUSPECTED ADVERSE REACTIONS, contact Merck Sharp & Dohme LLC at 1-877-888-4231 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. Adverse Reactions in Virologically-Suppressed Adults Living with HIV-1 Who Switched to IDVYNSO The safety assessment of IDVYNSO in virologically-suppressed (HIV-1 RNA less than 50 copies/mL) participants living with HIV was based on Week 48 data from two Phase 3, randomized trials, Trial 051 and Trial 052. A total of 708 participants received once-daily IDVYNSO [see Clinical Studies (14)]. In Trial 051, an open-label trial with 551 participants, 366 participants were switched to IDVYNSO and 185 participants continued their baseline antiretroviral therapy (ART). By Week 48, 0.5% in the IDVYNSO group and 2% in the baseline ART group had adverse events leading to discontinuation of study medication. In Trial 052, a double-blinded trial with 513 participants, 342 participants were switched to IDVYNSO and 171 participants continued on bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF). By Week 48, 3% in the IDVYNSO group and 2% in the BIC/FTC/TAF group had adverse events leading to discontinuation of study medication. Among participants who received IDVYNSO and experienced at least one adverse event in Trial 051 or Trial 052, 88% experienced only adverse events that were mild (Grade 1) or moderate (Grade 2). The most common adverse reactions (all grades) reported in greater than or equal to 2% of participants in any treatment group from Trial 051 and Trial 052 through Week 48 are presented in Table 1.
Table from the label
| Adverse Reactions | Trial 051 | Trial 052 | ||
|---|---|---|---|---|
| IDVYNSO N=366 | Baseline ART N=185 | IDVYNSO N=342 | BIC/FTC/TAF N=171 | |
| Diarrhea | 3% | 0 | 1% | 1% |
| Dizziness | 2% | 1% | 1% | 0 |
| FatigueFatigue includes fatigue and asthenia. | 2% | 1% | 1% | 1% |
| Abdominal distension | 2% | 0 | 1% | 0 |
| Headache | 2% | 1% | 1% | 0 |
| Weight increasedThe mean change in weight from baseline at Week 48 was 0.94 kg in the IDVYNSO group vs. -0.15 kg in the baseline ART group in Trial 051, and -0.03 kg in the IDVYNSO group vs. 0.28 kg in the BIC/FTC/TAF group in Trial 052. | 2%4 of the 6 participants with adverse reactions of weight increased switched from a baseline ART regimen containing efavirenz and/or tenofovir disoproxil fumarate in Trial 051. | 0 | <1% | 0 |
— FDA label: Idvynso, Merck Sharp & Dohme LLC, effective April 20, 2026. This is part of the section. Read the full label on DailyMed →
Doravirine, islatravir drug interactions
Quoted from the “Drug Interactions” section of the FDA-approved label. Tell your pharmacist about every medicine, vitamin and herbal product you take.
Because IDVYNSO is a complete regimen, co-administration with other antiretroviral medications for treatment of HIV-1 infection is not recommended. (7.1) Consult the full prescribing information prior to and during treatment for important potential drug-drug interactions.
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(2.2, 4, 5.2, 7, 12.3) 7.1 Concomitant Use with Other Antiretroviral Medications Because IDVYNSO is a complete regimen for the treatment of HIV-1 infection, co-administration with other antiretroviral medications for treatment of HIV-1 infection is not recommended. 7.2 Effects of Other Drugs on IDVYNSO Doravirine Co-administration of IDVYNSO with a CYP3A inducer decreases doravirine plasma concentrations, which may reduce the efficacy of IDVYNSO [see Contraindications (4), Warnings and Precautions (5.2), and Clinical Pharmacology (12.3)]. Co-administration of IDVYNSO and drugs that are inhibitors of CYP3A may result in increased plasma concentrations of doravirine. Islatravir Islatravir requires phosphorylation by cellular kinases to form the pharmacologically active ISL-TP. Co-administration of IDVYNSO and drugs that are substrates of dCK (e.g., certain nucleoside antiviral agents and nucleoside antimetabolites) may result in a decrease in ISL-TP concentrations and may reduce the therapeutic effect of islatravir [see Contraindications (4), Warnings and Precautions (5.2), and Clinical Pharmacology (12.3)]. Islatravir is subject to ADA-mediated metabolism (approximately 53%). Co-administration of IDVYNSO and drugs that are ADA inhibitors (e.g., pentostatin) may result in increased plasma concentrations of islatravir and may increase the risk of adverse reactions [see Warnings and Precautions (5.2) and Clinical Pharmacology (12.3)]. The drug interactions described in Table 3 are based on studies conducted with IDVYNSO, its components, or are predicted drug interactions that may occur with IDVYNSO. Table 3: Drug Interactions with IDVYNSO This table is not all inclusive. Concomitant Drug Class: Drug Name Effect on Concentration Clinical Comment ↑ = increase, ↓ = decrease Strong CYP3A Inducers ↓ doravirine Co-administration with strong CYP3A inducers is contraindicated At least a 4-week cessation period is recommended prior to initiation of IDVYNSO. Moderate CYP3A Inducers ↓ doravirine If IDVYNSO is co-administered with rifabutin Interactions were evaluated in clinical studies. All other drug-drug interactions are predicted., one tablet of doravirine (PIFELTRO) should be taken approximately 12 hours after the dose of IDVYNSO [see Dosage and Administration (2.2)]. Co-administration with other moderate CYP3A inducers is not recommended. dCK Substrates May include other nucleoside drugs Anti-virals lamivudine emtricitabine ↓ ISL-TP Co-administration is contraindicated with lamivudine or emtricitabine. Nucleoside Antimetabolites cladribine clofarabine cytarabine fludarabine gemcitabine ↓ ISL-TP Co-administration with these nucleoside antimetabolites is not recommended as dCK substrates may cause a decrease in the intracellular concentration of ISL-TP.
— FDA label: Idvynso, Merck Sharp & Dohme LLC, effective April 20, 2026. This is part of the section. Read the full label on DailyMed →
Doravirine, islatravir dosage
Quoted from the “Dosage and Administration” section of the FDA-approved label. Your own dose is the one your doctor prescribes: do not change it on your own.
Recommended dosage: One tablet taken orally once daily with or without food in adults. (2.1) Dosage adjustment with rifabutin: Take one tablet of IDVYNSO once daily, followed by one tablet of doravirine (PIFELTRO) 100 mg approximately 12 hours after the dose of IDVYNSO. (2.2) 2.1 Recommended Dosage The recommended dosage of IDVYNSO is one tablet taken orally once daily with or without food [see Clinical Pharmacology (12.3)].
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One tablet of IDVYNSO contains 100 mg doravirine and 0.25 mg islatravir. 2.2 Dosage Adjustment with Rifabutin If IDVYNSO is co-administered with rifabutin, take one tablet of IDVYNSO once daily as recommended, followed by one tablet of doravirine (PIFELTRO) 100 mg approximately 12 hours after the dose of IDVYNSO for the duration of rifabutin co-administration [see Drug Interactions (7.2) and Clinical Pharmacology (12.3)].
— FDA label: Idvynso, Merck Sharp & Dohme LLC, effective April 20, 2026. Read the full label on DailyMed →
Doravirine, islatravir in pregnancy
Quoted from the pregnancy part of the FDA-approved label. Ask your doctor before you take any medicine while pregnant or planning a pregnancy.
Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in individuals exposed to IDVYNSO during pregnancy. Healthcare providers are encouraged to register patients by calling the Antiretroviral Pregnancy Registry (APR) at 1-800-258-4263. Risk Summary There are insufficient human data on the use of IDVYNSO during pregnancy to inform a drug-associated risk of birth defects and miscarriage.
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In animal reproduction studies, no developmental effects were observed when the components of IDVYNSO were administered separately at exposures (AUC) at least 8 (doravirine) and 500 (islatravir) times the exposure at the recommended human dose (RHD) of these components in IDVYNSO (see Data.) The background rate of major birth defects is 2.7% in a U.S. reference population of the Metropolitan Atlanta Congenital Defects Program (MACDP). The rate of miscarriage is not reported in the APR. The estimated background rate of miscarriage in the clinically recognized pregnancies in the U.S. general population is 15-20%. Methodological limitations of the APR include the use of MACDP as the external comparator group. The MACDP population is not disease-specific, evaluates individuals and infants from the limited geographic area, and does not include outcomes for births that occurred at less than 20 weeks gestation. Data Animal Data Doravirine Doravirine was administered orally to pregnant rabbits (up to 300 mg/kg/day on Gestation Days (GD) 7 to 20) and rats (up to 450 mg/kg/day on GD 6 to 20 and separately from GD 6 to Lactation/Postpartum Day 20). No significant toxicological effects on embryo-fetal (rats and rabbits) or pre/post-natal (rats) development were observed at exposures (AUC) approximately 9 times (rats) and 8 times (rabbits) the exposure in humans at the RHD. Doravirine was transferred to the fetus through the placenta in embryo-fetal studies, with fetal plasma concentrations of up to 40% (rabbits) and 52% (rats) that of maternal concentrations observed on GD 20. Islatravir Islatravir was administered orally to pregnant rabbits (up to 10 mg/kg/day on GD 7 to 20) and rats (up to 50 mg/kg/day on GD 6 to 20 and separately up to 10 mg/kg from GD 6 to Lactation/Postpartum Day 20). No significant toxicological effects on embryo-fetal (rats and rabbits) or pre/post-natal (rats) development were observed at exposures (AUC) approximately 500 times (rats) and 1300 times (rabbits) the exposure in humans at the RHD. In rats, islatravir was transferred to the fetus through the placenta in rats, with fetal plasma concentrations of up to 88% that of maternal concentrations observed on GD 20.
— FDA label: Idvynso, Merck Sharp & Dohme LLC, effective April 20, 2026. Read the full label on DailyMed →
When Doravirine, islatravir should not be used
Quoted from the “Contraindications” section of the FDA-approved label.
IDVYNSO is contraindicated when co-administered with: drugs that are strong cytochrome P450 (CYP)3A enzyme inducers as significant decreases in doravirine plasma concentrations may occur, which may decrease the effectiveness of IDVYNSO [see Warnings and Precautions (5.2), Drug Interactions (7.2), and Clinical Pharmacology (12.3)]. lamivudine (3TC) or emtricitabine (FTC) as significant decreases in islatravir-triphosphate (ISL-TP) concentrations may occur, which may decrease the effectiveness of IDVYNSO [see Warnings and Precautions (5.2), Drug Interactions (7.2) and Clinical Pharmacology (12.3)].
Read more of this section
IDVYNSO is contraindicated when co-administered with drugs that are strong cytochrome P450 (CYP)3A enzyme inducers as significant decreases in doravirine plasma concentrations may occur, which may decrease the effectiveness of IDVYNSO. (4) IDVYNSO is contraindicated when co-administered with lamivudine (3TC) or emtricitabine (FTC), which are deoxycytidine kinase (dCK) substrates, as a decrease in islatravir-triphosphate (ISL-TP) levels may occur, which may decrease the effectiveness of IDVYNSO. (4)
— FDA label: Idvynso, Merck Sharp & Dohme LLC, effective April 20, 2026. Read the full label on DailyMed →
Doravirine, islatravir overdose
Quoted from the “Overdosage” section of the FDA-approved label. If someone may have taken too much, call Poison Help at 1-800-222-1222 (or 911 in an emergency).
No data are available on overdose of IDVYNSO and there is no known specific treatment for overdose with IDVYNSO. If overdose occurs, the person should be monitored, and standard supportive treatment applied as required.
— FDA label: Idvynso, Merck Sharp & Dohme LLC, effective April 20, 2026. Read the full label on DailyMed →
Forms and how it is given
| Dosage forms | Tablet, film coated |
|---|---|
| Route | Oral |
| Prescription products | 1 in the FDA NDC Directory |
| Brand names | Idvynso |
Companies that list this medicine
Labelers in the FDA NDC Directory: the company named on the package (maker or distributor), with the number of prescription products.
- Merck Sharp & Dohme LLC1 product
FDA approval history
- NDA: New Drug Application: how a new (usually brand-name) medicine is approved.
| Application | Sponsor | Approved | Later changes approved |
|---|---|---|---|
| NDA216964 IDVYNSO | Msd | April 20, 2026 | — |
Shortage status
The FDA drug shortage list does not show these products.
Recalls
No recall linked to these products (by their NDC code) appears in the FDA enforcement reports.
Official identifiers
| RxCUI (RxNorm) | 2741694, 2741700 |
|---|---|
| SPL set ID of the quoted label | 11aaeb53-9848-433c-be7f-db8a5bc0b26f |
| FDA labels (SPL) | 1 |
| FDA applications | NDA216964 |
| Active ingredients (FDA) | DORAVIRINE / ISLATRAVIR |
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Sources
- FDA-approved label on DailyMed (National Library of Medicine) — Idvynso, Merck Sharp & Dohme LLC, effective April 20, 2026; via openFDA, FDA data exported October 30, 2026, retrieved October 31, 2026
- NDC Directory (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 30, 2026, retrieved October 31, 2026
- Drugs@FDA (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 30, 2026, retrieved October 31, 2026
- Drug recall enforcement reports (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 27, 2026, retrieved October 31, 2026
- Drug shortages (openFDA) — U.S. Food and Drug Administration (FDA), FDA data exported October 30, 2026, retrieved October 31, 2026
openFDA data is provided by the FDA as is; it may be incomplete. Always rely on the label that comes with your medicine. FDA Enforcement Report search →