Alirocumab !

A monoclonal antibody against PCSK9, injected every 2 or 4 weeks. It lowers LDL strongly and reduces cardiovascular events.

Updated 2026-11-01

Class: PCSK9 inhibitors
Target: PCSK9 (circulating protein)
ATC code: C10AX14

PCSK9 (circulating protein)Alirocumab

The figure shows PCSK9 bound to the EGF-A domain of the LDL receptor. Alirocumab binds PCSK9 and blocks this contact; the antibody itself is not in this structure.

Target in 3D: PCSK9 (circulating protein). PDB structure 3BPS (RCSB PDB, public domain). View the structure at RCSB PDB

Mechanism of action

Alirocumab is a human monoclonal antibody that binds circulating PCSK9 and prevents it from binding the LDL receptor. Without PCSK9 the receptor escapes lysosomal destruction and recycles to the liver cell surface, so more LDL is cleared.

Antibody binds circulating PCSK9
PCSK9 cannot send LDL receptors to the lysosome
More receptors on hepatocytes clear LDL

Pharmacokinetics

Absorption: Subcutaneous injection once every 2 or 4 weeks.
Elimination: Broken down like other antibodies and proteins, not by liver CYP enzymes.

Indications

Established atherosclerotic cardiovascular disease, to lower the risk of heart attack and stroke Atherosclerosis and dyslipidaemia →
Heterozygous familial hypercholesterolemia, with other LDL-lowering drugs Familial hypercholesterolemia →

Adverse effects

Common

Injection-site redness, itching, swelling or pain
Flu-like symptoms, fever, headache, chills

Contraindications

Serious hypersensitivity to alirocumab or an excipient

Key interactions

Statins and ezetimibe: Used together on purpose: LDL-lowering effects add up. No known pharmacokinetic drug interactions.

What is monitored

Lipid panel some weeks after starting or changing the dose
Injection sites and allergic symptoms

Administration and safety

Subcutaneous injection in the thigh, abdomen or upper arm; sites rotated.
Warmed to room temperature for about 30 to 40 minutes before use; never shaken.
Clear to pale yellow; not used if cloudy or with particles.
If more than one pen is needed for a dose, they are given one right after the other.

Nursing care

Before: lipid panel and allergy history.
Teach injection, storage in the refrigerator and sharps disposal.
Teach the signs of a serious allergic reaction.
Remind that the statin and diet continue.

Pregnancy and breastfeeding

Human data are limited; use in pregnancy is weighed case by case.

Test yourself

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

What do alirocumab and evolocumab have in common?

Both are monoclonal antibodies that bind PCSK9, preserve LDL receptors and lower LDL strongly.

Why is alirocumab used together with a statin rather than instead of it?

Their effects add up: the statin raises LDL receptor production, and the antibody keeps those receptors from being destroyed.

What is the main serious adverse effect to teach patients on alirocumab?

Allergic reactions (rash, hives, swelling, difficulty breathing), which need urgent care.

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

Sources: Alirocumab Injection: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); PCSK9:EGF-A complex (RCSB Protein Data Bank, 2008); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 37 (McGraw Hill, 2023); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.