Short answer: In the Voxzogo label's 52-week trial in children 5 and older, the most common side effects were injection site redness (75% vs 69% on placebo), injection site swelling (62% vs 36%), vomiting (27% vs 20%), injection site hives (25% vs 10%), joint pain (15% vs 7%) and lower blood pressure (13% vs 5%). There is no boxed warning; the one warning is a brief drop in blood pressure.
What Voxzogo is approved for: Voxzogo is a C type natriuretic peptide (CNP) analog approved to increase linear growth in children with achondroplasia whose growth plates (epiphyses) are still open. It has accelerated approval based on faster yearly growth, and continued approval may depend on confirmatory trials (section 1).
Source
VOXZOGO (vosoritide) for injection, for subcutaneous use, prescribing information, Patient Information and Instructions for Use. BioMarin. DailyMed, version published November 26, 2025. DailyMed setid 228e8560-04a4-4bb1-a81f-29531a9e4d27
No. The current Voxzogo label has no boxed warning.
These are the label's own numbers from the Adverse Reactions section. Where the label compares with placebo (a dummy treatment), both columns are shown, so you can see how much more often a reaction happened on Voxzogo.
| Adverse Reaction | Placebo (N=61) n (%) | VOXZOGO (N=60) n (%) |
|---|---|---|
| Injection site erythema | 42 (69%) | 45 (75%) |
| Injection site swelling | 22 (36%) | 37 (62%) |
| Vomiting | 12 (20%) | 16 (27%) |
| Injection site urticaria | 6 (10%) | 15 (25%) |
| Arthralgia | 4 (7%) | 9 (15%) |
| Decreased blood pressure | 3 (5%) | 8 (13%) |
| Gastroenteritis | 5 (8%) | 8 (13%) |
| Diarrhea | 2 (3%) | 6 (10%) |
| Dizziness | 2 (3%) | 6 (10%) |
| Ear pain | 3 (5%) | 6 (10%) |
| Influenza | 3 (5%) | 6 (10%) |
| Fatigue | 2 (3%) | 5 (8%) |
| Seasonal allergy | 1 (2%) | 4 (7%) |
| Dry skin | 0 | 3 (5%) |
121 children aged 5 to 14 years with achondroplasia, 52 weeks, Voxzogo 15 mcg/kg or placebo once a day. The table lists reactions more common on Voxzogo by a difference of at least 5% (more than 2 children). Gastroenteritis, dizziness and fatigue each group related terms.
Blood alkaline phosphatase rose in 17% on Voxzogo vs 7% on placebo.
Brief drops in blood pressure happened in 8 of 60 children (13%) on Voxzogo vs 3 of 61 (5%) on placebo, starting a median of 31 minutes after the injection and resolving within a median of 31 minutes. 2 children (3%) on Voxzogo had one episode each with vomiting or dizziness.
Any injection site reaction happened in 85% on Voxzogo vs 82% on placebo, but much more often per child: 120.4 vs 29.2 events per person-year.
In a 52-week study of 64 children aged 4.4 months to under 5 years, the most common reactions were injection site reactions (86%) and rash (28%), and the overall safety was similar to older children.
Reported after approval: extra hair growth (hypertrichosis).
The Warnings and Precautions part of the label lists these. Each line gives the label's heading and what it means in plain words.
Risk of low blood pressure. Brief drops in blood pressure were seen in clinical studies. Children with significant heart or blood vessel disease and those on blood pressure medicines were not included in the trials. To lower the risk of a drop and its symptoms (dizziness, tiredness or nausea), the label says the child eats enough and drinks about 240 to 300 mL of fluid in the hour before each dose.
Reduced kidney function. Voxzogo is not recommended for people with an eGFR under 60 mL/min/1.73 m2.
Who should not use it. The label lists no contraindications.
From the Patient Information that comes with Voxzogo:
Dose Track has a side-effect log. Each entry records the symptom, a severity (none, mild, moderate, severe or life-threatening), the date and an optional note, and can be tied to a specific dose or logged on its own. The history screen shows what you logged over time, which makes it easier to tell your prescriber when a reaction started and whether it is easing. The app records what you enter; it does not judge whether a symptom is serious. For anything on the label's call-your-doctor list, call your doctor.
This page is what the FDA label says, in plain words. It is not medical advice. Follow your prescriber, and ask them or your pharmacist about anything here.