Short answer: In the Praluent label's nine placebo-controlled trials in adults, the side effects reported more often than on placebo were injection site reactions (7% vs 5%), flu (6% vs 5%), diarrhea (5% vs 4%), muscle pain (4% vs 3%), muscle spasms (3% vs 2%) and bruising (2% vs 1%). There is no boxed warning; the one warning is serious allergic reactions, including vasculitis and angioedema.
What Praluent is approved for: Praluent is a PCSK9 inhibitor approved to lower the risk of major heart and blood vessel events (death from coronary heart disease, heart attack, stroke, or unstable angina needing a hospital stay) in adults at increased risk, and, alongside diet and exercise, to lower LDL cholesterol in adults with high cholesterol, adults and children 8 and older with heterozygous familial hypercholesterolemia (HeFH), and adults with homozygous familial hypercholesterolemia (HoFH) (section 1).
Source
PRALUENT (alirocumab) injection, for subcutaneous use, prescribing information, Patient Information and Instructions for Use. Sanofi. DailyMed, version published July 24, 2026. DailyMed setid 446f6b5c-0dd4-44ff-9bc2-c2b41f2806b4
No. The current Praluent 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 Praluent.
| Adverse Reactions | Placebo (N=1,276) % | PRALUENT 75 mg every 2 weeks and 150 mg every 2 weeks combined (N=2,476) % |
|---|---|---|
| Injection site reactions | 5 | 7 |
| Influenza | 5 | 6 |
| Diarrhea | 4 | 5 |
| Myalgia | 3 | 4 |
| Muscle spasms | 2 | 3 |
| Contusion | 1 | 2 |
2,476 adults with high cholesterol on 75 mg or 150 mg every 2 weeks, median 65 weeks. Side effects led to stopping in 5.3% on Praluent vs 5.1% on placebo, most often allergic reactions (0.6% vs 0.2%). Injection site reactions include redness, itching, swelling and pain.
In the heart outcomes trial (9,451 adults on Praluent, median 31 months), muscle pain was 6% vs 5% on placebo. Injection site reactions were 3.8% vs 2.1% and led 0.3% to stop for good.
In a 48-week trial, injection site reactions were 16.6% on 300 mg every 4 weeks, 9.6% on 75 mg every 2 weeks and 7.9% on placebo; 0.7% stopped the 300 mg dose because of them.
Allergic reactions were 8.6% on Praluent vs 7.8% on placebo, most often itching (1.1% vs 0.4%). Serious reactions such as nummular eczema and hypersensitivity vasculitis were reported in trials.
Liver-related problems, mostly liver enzyme changes, were 2.5% on Praluent vs 1.8% on placebo. Liver enzymes above 3 times normal: 1.7% vs 1.4%.
In 101 children aged 8 to 17 with HeFH over 24 weeks, the safety profile was consistent with adults. Injection site reactions were 5% vs 0% on placebo.
Reported after approval: angioedema (swelling under the skin) and flu-like illness.
The Warnings and Precautions part of the label lists these. Each line gives the label's heading and what it means in plain words.
Allergic reactions. Allergic reactions, including inflammation of blood vessels (hypersensitivity vasculitis), angioedema and reactions needing a hospital stay, have been reported. If signs of a serious reaction appear, Praluent is stopped, the reaction is treated and the person is watched until it clears.
Who should not use it. People with a history of a serious allergic reaction to alirocumab or any ingredient in Praluent.
From the Patient Information that comes with Praluent:
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.