[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [FGF23-blocking antibodies](https://durgical.com/en/pharmacology/classes/fgf23-blocking-antibodies/) › Burosumab

# Burosumab

## FGF23-blocking antibodies?

FGF23-blocking antibodies

An antibody injection against FGF23. It stops phosphate loss in the urine and heals rickets in X-linked hypophosphataemia.

Updated Nov 1, 2026

Also called: Burosumab-twza

## Quick facts

**Group**
[FGF23-blocking antibodies](https://durgical.com/en/pharmacology/classes/fgf23-blocking-antibodies/)

**Target**
Fibroblast growth factor 23 (FGF23)

**Used for**
X-linked hypophosphataemia

**Key effects**
Injection-site reactions · Headache · Pain in the arms

**Monitor**
Fasting serum phosphate before

**ATC**
M05BX05

No doses: the clinician sets them by the current guideline.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

Burosumab is a recombinant human monoclonal antibody that binds and neutralises FGF23. Excess FGF23 in X-linked hypophosphataemia and tumour-induced osteomalacia makes the kidney lose phosphate and suppresses calcitriol. With FGF23 blocked, proximal tubular phosphate reabsorption and calcitriol production recover, serum phosphate rises and bone mineralisation improves.

- Burosumab binds circulating FGF23
- The kidney reabsorbs more phosphate
- Calcitriol production recovers
- Serum phosphate rises and rickets or osteomalacia heals

## Indications

- X-linked hypophosphataemia in people aged 6 months and older [Rickets and osteomalacia →](https://durgical.com/en/conditions/rickets-and-osteomalacia/)
- Tumour-induced osteomalacia that cannot be removed surgically, in people aged 2 years and older [Hypophosphataemia →](https://durgical.com/en/conditions/hypophosphataemia/)

## Adverse effects

### Common

- Injection-site reactions (redness, rash, swelling, bruising)
- Headache, dizziness and fever
- Pain in the arms, legs or back, and muscle pain
- Vomiting and constipation

### Serious (rare, important)

- Hypersensitivity reactions (rash, hives)
- Restless legs syndrome, new or worse
- High serum phosphate and nephrocalcinosis

## Contraindications

- Use with oral phosphate or active vitamin D analogues
- Serum phosphate within or above the normal range
- Severe kidney impairment or end-stage kidney disease

## Key interactions

**Oral phosphate supplements**
Stopped a week before starting: risk of too much phosphate

**Active vitamin D (calcitriol, paricalcitol)**
Stopped a week before starting: risk of high phosphate and calcium

## What is monitored

- Fasting serum phosphate before and during treatment; doses may be held
- Kidney function and signs of nephrocalcinosis
- Symptoms of restless legs
- Growth and rickets healing in children

## Administration and safety

- Subcutaneous injection into the upper arm, upper thigh, buttock or abdomen, with a different site each time
- Given by a doctor or nurse
- Phosphate and active vitamin D supplements are stopped beforehand

## Pregnancy and breastfeeding

Information in pregnancy is limited; the prescriber is told about pregnancy, plans for pregnancy or breastfeeding.

## Nursing care

- Confirm that phosphate and active vitamin D supplements were stopped
- Check phosphate results before each dose
- Inspect injection sites and ask about rash or itching
- Ask about leg discomfort and an urge to move the legs

## Pharmacokinetics

**Absorption**
Given by subcutaneous injection by a health professional, at intervals set by age and condition

## Memory aid

BUROsumab BURies FGF23, so the kidney keeps its phosphate.

## Test yourself

Think of the answer, then tap the question to see it.

## What does burosumab bind?

Fibroblast growth factor 23 (FGF23), the hormone that causes renal phosphate wasting in X-linked hypophosphataemia.

## Which supplements must be stopped before burosumab?

Oral phosphate and active vitamin D such as calcitriol or paricalcitol.

## Which blood test guides burosumab treatment?

Serum phosphate, checked before and during treatment; doses are held if it is too high.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/burosumab/)

[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## Connections

## Related drugs 1

- [Calcitriol](https://durgical.com/en/pharmacology/calcitriol/)

## Related conditions 2

- [Rickets and osteomalacia](https://durgical.com/en/conditions/rickets-and-osteomalacia/)
- [Hypophosphataemia](https://durgical.com/en/conditions/hypophosphataemia/)

[← Back to the class: FGF23-blocking antibodies](https://durgical.com/en/pharmacology/classes/fgf23-blocking-antibodies/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [Burosumab-twza Injection: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a618034.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=M05BX05) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/pharmacology/burosumab/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/burosumab/