Voxelotor
Voxelotor is a once-daily medicine that treats sickle cell disease in adults and children 4 years and older by helping stop sickle-shaped red blood cells from forming.
🧬 Where this information comes from Click to expand
The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 1 clinical label set within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →
Voxelotor (Oxbryta) is a once-daily specialist medicine for sickle cell disease in people 4 and older that makes hemoglobin hold oxygen more tightly, so the abnormal hemoglobin S is less likely to clump and bend red cells into sickles. On the U.S. market since about 2019, it won accelerated (early) approval based on rising hemoglobin rather than proven fewer complications. Most people tolerate it fairly well, mainly noticing headache, diarrhea, belly pain or nausea. Watch for a serious allergic reaction (spreading rash, hives, facial swelling, shortness of breath), which needs help right away. Its maker has since withdrawn it worldwide over safety concerns from later studies, so check with your prescriber before taking any leftover supply.
Clinical pearls
- Swallow tablets whole (no cutting, crushing or chewing), with or without food, and resume the next day after a missed dose.
- It can skew lab tests that sort hemoglobin types, so tell whoever orders them; precise results need 10 days off it.
- Medicines that speed up liver breakdown (strong or moderate CYP3A4 inducers) can weaken it, so have each new prescription screened.
- It can raise levels of sensitive drugs such as the sedative midazolam, worth flagging before any procedure needing sedation.
Patient information guide A plain-language walkthrough of Voxelotor, written from its FDA label.
What Voxelotor is used for
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Voxelotor is used for one condition.
- Oxbryta treats sickle cell disease in adults and children 4 years and older.
- The approval is accelerated, based on increased hemoglobin. Continued approval may depend on confirmatory trials showing clinical benefit.
How Voxelotor works
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Voxelotor is a hemoglobin S polymerization inhibitor. It binds to hemoglobin S, the abnormal hemoglobin in sickle cell disease, and collects mainly inside red blood cells. By helping hemoglobin hold oxygen more tightly, it reduces the clumping that distorts red cells.
Lab studies suggest it may reduce sickling, improve red cell flexibility, and lower blood thickness.
Voxelotor dosage
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Oxbryta is taken by mouth once daily, with or without food. Regular tablets must be swallowed whole, not cut, crushed, or chewed.
- If you miss a dose or can't take it all, resume the next day.
- It may be used with or without hydroxyurea.
- Dose depends on age, body weight, liver function, and some other medicines. Follow your prescriber and label.
Dosing details from the FDA-approved label
From the Voxelotor prescribing information (“Dosage and Administration”). Doses are set by your prescriber for your product, condition, kidney function and age — never change a dose on your own.
- Adults and pediatric patients 12 years and older
- 1,500 mg orally once daily
- Can be taken with or without food
- Pediatric patients 4 years to less than 12 years, 40 kg or greater
- 1,500 mg once daily
- Dosing based on body weight
- Pediatric patients 4 years to less than 12 years, 20 kg to less than 40 kg
- 900 mg once daily
- Dosing based on body weight
- Pediatric patients 4 years to less than 12 years, 10 kg to less than 20 kg
- 600 mg once daily
- Dosing based on body weight
- Adults and pediatric patients 12 years and older with severe hepatic impairment (Child Pugh C)
- 1,000 mg orally once daily
- No dosage adjustment for mild or moderate hepatic impairment
- Pediatric patients 4 years to less than 12 years with severe hepatic impairment (Child Pugh C), 40 kg or greater
- 1,000 mg (two 500 mg tablets) or 900 mg (three 300 mg tablets for oral suspension or three 300 mg tablets) once daily
- Weight-based
- Pediatric patients 4 years to less than 12 years with severe hepatic impairment (Child Pugh C), 20 kg to less than 40 kg
- 600 mg once daily
- Weight-based
- Pediatric patients 4 years to less than 12 years with severe hepatic impairment (Child Pugh C), 10 kg to less than 20 kg
- 300 mg once daily
- Weight-based
- Adults and pediatric patients 12 years and older with unavoidable concomitant strong CYP3A4 inducers
- 2,500 mg orally once daily
- Avoid concomitant use if possible
- Adults and pediatric patients 12 years and older with unavoidable concomitant moderate CYP3A4 inducers
- 2,000 mg orally once daily
- Avoid concomitant use if possible
Read the label’s full dosing text
2 DOSAGE AND ADMINISTRATION OXBRYTA can be taken with or without food. ( 2.7 ) Recommended dosage: • Adults and pediatric patients 12 years and older: 1,500 mg orally once daily. ( 2.1 ) • Pediatric patients 4 to less than 12 years: Dosing with OXBRYTA is based on body weight. See Table 1 for complete dosing recommendations. ( 2.2 ) Recommended dosage for severe hepatic impairment (Child Pugh C) : • Adults and pediatric patients 12 years and older: 1,000 mg orally once daily. ( 2.3 ) • Pediatric patients 4 to less than 12 years: Reduce the dose of OXBRYTA based on body weight. See Table 2 for complete dosing recommendations. ( 2.4 ) 2.1 Recommended Dosage for Adults and Pediatric Patients 12 Years and Older The recommended dosage of OXBRYTA is 1,500 mg orally once daily. 2.2 Recommended Dosage for Pediatric Patients 4 Years to Less Than 12 Years For pediatric patients 4 years to less than 12 years, select the appropriate product (OXBRYTA tablets or OXBRYTA tablets for oral suspension) based on patient's ability to swallow tablets and patient's weight. The recommended dosage of OXBRYTA for pediatric patients 4 years to less than 12 years is shown in Table 1. Table 1: Recommended OXBRYTA Dosage in Pediatric Patients 4 Years to Less Than 12 Years Body Weight Recommended Dose (once daily) 40 kg or greater 1,500 mg 20 kg to less than 40 kg 900 mg 10 kg to less than 20 kg 600 mg 2.3 Recommended Dosage for Adults and Pediatric Patients 12 Years and Older with Hepatic Impairment The recommended dosage of OXBRYTA in adults and pediatric patients 12 years and older with severe hepatic impairment (Child Pugh C) is 1,000 mg orally once daily. No dosage adjustment of OXBRYTA is required for patients with mild or moderate hepatic impairment [ see Use in Specific Populations (8.6) and Clinical Pharmacology (12.3) ]. 2.4 Recommended Dosage for Pediatric Patients 4 Years to Less Than 12 Years with Hepatic Impairment The recommended dosage of OXBRYTA in pediatric patients 4 years to less than 12 years with severe hepatic impairment (Child Pugh C) is described in Table 2. No dosage adjustment of OXBRYTA is required for patients with mild or moderate hepatic impairment [see Use in Specific Populations (8.6) and Clinical Pharmacology (12.3) ] .
Excerpted — the section continues on the label. Read the full Dosage and Administration section on DailyMed →
Voxelotor side effects
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The most common side effects in clinical studies were:
Common side effects
- Headache
- Diarrhea
- Abdominal (belly) pain
- Nausea
- Rash
- Fever
When to get medical help
- Get medical help right away for signs of a serious allergic reaction, such as a widespread rash, hives, shortness of breath, or facial swelling.
- Call your doctor if a rash or other new symptoms appear after starting the medicine.
- Tell your doctor if side effects become severe or don't go away.
Voxelotor warnings and precautions
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The biggest risk is serious hypersensitivity (allergic) reactions. Watch for rash, hives, shortness of breath, or facial swelling, and get help promptly.
Voxelotor can also interfere with lab tests that measure hemoglobin types. Precise testing should be done when you haven't taken it for the preceding 10 days.
Voxelotor interactions
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Some medicines can change how voxelotor works, or how it affects other drugs.
- Strong or moderate CYP3A4 inducers: can lower voxelotor levels and reduce its effect. Avoid if possible; the dose may be raised if unavoidable.
- Sensitive CYP3A4 substrates with a narrow therapeutic index (such as midazolam): voxelotor can raise their levels. Avoid, or consider lowering the other drug's dose.
Interactions listed in the FDA-approved label
From the Voxelotor prescribing information (“Drug Interactions”): what the manufacturer studied or reported to the FDA.
- Strong or moderate CYP3A4 inducers: Coadministration may decrease voxelotor plasma and whole blood concentrations and may lead to reduced efficacy. Avoid coadministration; if unavoidable, increase the OXBRYTA dosage.
- Sensitive CYP3A4 substrates with a narrow therapeutic index (e.g., midazolam): Voxelotor increased the systemic exposure of midazolam, a sensitive CYP3A4 substrate. Avoid coadministration; if concomitant use is unavoidable, consider dose reduction of the sensitive CYP3A4 substrate(s).
- Laboratory measurement of Hb subtypes (HbA, HbS, HbF) by HPLC: OXBRYTA administration may interfere with measurement of Hb subtypes by HPLC. If precise quantitation of Hb species is required, perform chromatography when the patient has not received OXBRYTA therapy in the immediately preceding 10 days.
Read the label’s full interactions text
7 DRUG INTERACTIONS • Sensitive CYP3A4 Substrates: Avoid coadministration of sensitive CYP3A4 substrates with a narrow therapeutic index. ( 7.2 ) • Strong or moderate CYP3A4 Inducers: Avoid coadministration with strong or moderate CYP3A4 inducers. If unavoidable, increase the dose of OXBRYTA. ( 2.5 , 2.6 , 7.1 ) 7.1 Effect of Other Drugs on Voxelotor Strong or Moderate CYP3A4 Inducers Coadministration of strong or moderate CYP3A4 inducers may decrease voxelotor plasma and whole blood concentrations and may lead to reduced efficacy. Avoid coadministration of OXBRYTA with strong or moderate CYP3A4 inducers. Increase the OXBRYTA dosage when coadministration with a strong or moderate CYP3A4 inducer is unavoidable [see Dosage and Administration (2.5 , 2.6) and Clinical Pharmacology (12.3) ]. 7.2 Effect of Voxelotor on Other Drugs Voxelotor increased the systemic exposure of midazolam (a sensitive CYP3A4 substrate) [see Clinical Pharmacology (12.3) ]. Avoid coadministration of OXBRYTA with sensitive CYP3A4 substrates with a narrow therapeutic index. If concomitant use is unavoidable, consider dose reduction of the sensitive CYP3A4 substrate(s). 7.3 Laboratory Test Interference OXBRYTA administration may interfere with measurement of Hb subtypes (HbA, HbS, and HbF) by HPLC [see Warnings and Precautions (5.2) ]. If precise quantitation of Hb species is required, chromatography should be performed when the patient has not received OXBRYTA therapy in the immediately preceding 10 days.
Not a complete list. The label covers the interactions the manufacturer studied or reported, and our own interaction database does not cover every medicine either. Bring your full medication list, including vitamins and herbal products, to your pharmacist.
Before taking Voxelotor
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- Do not use if you've had a serious allergic reaction to voxelotor or its ingredients.
- Severe liver impairment (Child Pugh C) needs a lower dose. Mild or moderate liver impairment needs no adjustment.
- Pregnancy: use only if the benefit outweighs the potential risk. Sickle cell disease itself raises pregnancy risks.
- Breastfeeding is not recommended during treatment and for at least 2 weeks after the last dose.
- Children under 4: safety and effectiveness have not been established.
What Voxelotor does in the body
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Voxelotor increases hemoglobin's attraction to oxygen in a dose-dependent way. It also reduces measures of red blood cell breakdown (hemolysis), such as indirect bilirubin and reticulocyte percentage. At levels about twice the therapeutic range, it did not meaningfully prolong the QT interval (a heart rhythm measure).
How your body processes Voxelotor
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After you swallow it, voxelotor reaches peak plasma levels in about 2 hours. It then moves mostly into red blood cells, where levels peak 6 to 18 hours after a dose. Its half-life is about 38.7 hours, and steady levels are reached within 8 days. A high-fat, high-calorie meal raised drug levels. The body breaks it down extensively in the liver, and the remains leave through feces and urine.
How to store Voxelotor
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Store OXBRYTA at 20°C to 30°C (68°F to 86°F).
Written from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
Supplements & herbs that interact with Voxelotor
143 supplements and herbal products have documented interactions with Voxelotor in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.
- Major · 3
- Moderate · 100
- Minor · 40
Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.
Voxelotor: pharmacist answers to common questions
Quick, plain-English answers to the questions patients ask most about Voxelotor — the kind of thing our pharmacy team would talk through with you at the counter.
What is this medicine for?
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How do I take it?
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What side effects should I expect?
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When should I call my doctor right away?
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Can I take it with my other medicines?
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Is it safe during pregnancy or breastfeeding?
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Is Voxelotor available over the counter?
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When was Voxelotor first available?
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Answers drafted from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
More about Voxelotor on HelloPharmacist
Voxelotor forms and strengths (how it comes)
Voxelotor is available in 1 form. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.
Tablet
How this form is used
- Oxbryta is used to treat sickle cell disease in adults and children 4 years and older.
- Oxbryta tablets are taken by mouth once daily, with or without food.
- Swallow Oxbryta tablets whole. Do not cut, crush, or chew them.
- If an Oxbryta dose is missed or not taken fully, resume dosing the next day.
Voxelotor on the U.S. market: products, makers and brands
How Voxelotor appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.
1 company lists 3 Voxelotor product records with the FDA, mostly as tablet; the earliest marketing or approval year on record is 2019. Brand names on the directory include Oxbryta; the rest are generics.
Also listed with the FDA, not a patient dose form: Powder (5) — bulk drug substance sold to compounders/manufacturers and multi-item kits. These aren’t counted in the dose-form total above.
Compare Voxelotor products
A representative set of FDA-listed product records for Voxelotor — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)
| Strength | Route | Manufacturer / Labeler | Category ⓘ | Details |
|---|---|---|---|---|
| 💊Tablet | ||||
| 300 mg | Oral | Global Blood Therapeutics, Inc, A subsidiary of Pfizer Inc. × 2 listings | NDA | View NDC → |
| 500 mg | Oral | Global Blood Therapeutics, Inc, A subsidiary of Pfizer Inc. | NDA | View NDC → |
Showing 3 of 3 products — FDA National Drug Code Directory. See every product, package size and price: browse all 3 Voxelotor NDCs →
Voxelotor side effects reported to the FDA (FAERS)
After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for Voxelotor — a signal of what to watch for, not proof the drug caused it.
Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists Voxelotor in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.
Voxelotor FDA approval history
How Voxelotor went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
Voxelotor recall history
A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.
The FDA’s enforcement reports list no Voxelotor recalls since July 2021.
✅No Voxelotor recalls on record since July 2021Source: FDA enforcement (recall) reports, via openFDA; our copy was last updated Sep 24, 2026.
RxNorm Concept Web — From Ingredient to Every Form and Strength
This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.
RxCUI 2265678 2 dose forms · 3 strengths
-
Dose form (SCDF) Oral Tablet RxCUI 2265682In current FDA listings -
Dose form (SCDF) Tablet for Oral Suspension RxCUI 2588069In current FDA listingsClinical drug / strength (SCD) 300 MGRxCUI 2588070
Look up RxCUI 2265678 in the RxCUI Atlas →
RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.
Voxelotor supply and shortage status
Whether Voxelotor is in short supply in the U.S. right now, plus any shortage history the FDA has on record. A shortage usually reflects a manufacturing or demand issue — not a safety problem with the drug.
Source: openFDA, from the FDA Drug Shortages database.
Voxelotor brand names
Voxelotor is sold under one brand name in the FDA directory — Oxbryta. A brand and its generic contain the same active ingredient; the brand name belongs to one company's product.
Who makes Voxelotor: manufacturers and labelers
One company lists Voxelotor products with the FDA. By number of product records, the largest are Global Blood Therapeutics, Inc, A subsidiary of Pfizer Inc.. Labelers include manufacturers and repackagers; the product in your bottle depends on which one your pharmacy stocks.
Voxelotor drug class (RxNorm)
Voxelotor belongs to the Hemoglobin S Polymerization Inhibitor class.
Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.
Sources for this Voxelotor page
Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.
How this page is built
HelloPharmacist combines public FDA and NLM records and does not author the underlying clinical facts. The plain-language sections are written with AI from the FDA-approved label text and reviewed by our pharmacy team before publication. Global Blood Therapeutics, Inc, A subsidiary of Pfizer Inc. is the representative DailyMed label linked for verification and dates. This is general education, not medical advice: always talk to your doctor or pharmacist about your own medicines. How we build and review drug pages →