voxelotor at a glance
Medicine class
Haemoglobin S polymerisation inhibitor.
Previous licensed role
Treatment of haemolytic anaemia caused by sickle cell disease, alone or with hydroxycarbamide.
Current status
Withdrawn from the UK market; new patients should not start treatment.
Tablet administration
Former instructions stated tablets should be swallowed whole with water and could be taken with or without food.
What is voxelotor used for?
Voxelotor was previously licensed for haemolytic anaemia caused by sickle cell disease. As UK supplies have been withdrawn, it should no longer be initiated.
Previously licensed for adults and young people aged 12 years and older.
Previously authorised alone or alongside hydroxycarbamide.
How does voxelotor work?
Voxelotor binds preferentially to haemoglobin S inside red blood cells and increases haemoglobin’s affinity for oxygen. This inhibits haemoglobin S polymer formation, reducing red-cell sickling and improving cell deformability; laboratory measures of haemolysis may fall.
voxelotor preparations and strengths
Tablet
Route: Oral
Strengths: 500 mg
How to take voxelotor
Voxelotor should not now be started in the UK. Anyone with tablets should contact their sickle-cell specialist or hospital pharmacy and return remaining packs as directed. Former instructions stated tablets should be swallowed whole with water and not cut, crushed or chewed.
Do not restart tablets from an earlier supply without speaking to the specialist team.
Follow hospital pharmacy instructions for returning remaining packs.
voxelotor side effects
Common or expected effects
- Headache
- Diarrhoea
- Abdominal pain
- Nausea
- Rash
- Itching
Get urgent medical advice
- Allergic reaction with breathing difficulty, hives or facial swelling
- Angioedema affecting the eyelids, face or lips
- Drug reaction with eosinophilia and systemic symptoms (DRESS), which may cause widespread rash, fever, facial swelling and internal-organ involvement
- Sudden clinical deterioration or an acute painful sickle-cell crisis requires prompt assessment
voxelotor in pregnancy
Human pregnancy information is limited. The former SmPC advised avoiding voxelotor during pregnancy as a precaution. Anyone who becomes pregnant after recent exposure should contact their sickle-cell and maternity teams.
voxelotor while breastfeeding
It is unknown whether voxelotor enters human milk, and a risk to the infant cannot be excluded. The former SmPC stated that it should not be used while breastfeeding; seek specialist advice after recent exposure.
voxelotor interactions
These interactions remain relevant when reviewing recent or past exposure. Include prescribed, over-the-counter and herbal products in a medication review.
Rifampicin, carbamazepine, phenytoin, phenobarbital and St John’s wort
Strong CYP3A4 induction can lower voxelotor exposure and reduce its effect.
Tacrolimus, sirolimus and alfentanil
Voxelotor can increase exposure to sensitive CYP3A4 substrates with a narrow therapeutic range.
Bupropion and efavirenz
Voxelotor may affect CYP2B6 metabolism; the clinical importance is uncertain.
Common questions about voxelotor
Answers are fully visible for fast scanning and source review.
Is voxelotor still available in the UK?
No. All UK batches were recalled and the product was withdrawn from the market in September 2024.
Why was voxelotor withdrawn?
Emerging clinical-trial and registry evidence suggested an unfavourable imbalance in painful sickle-cell crises and deaths, so its overall benefit was judged not to outweigh the risk.
What should I do with leftover tablets?
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.