Alirocumab (praluent)?

Alirocumab (brand name Praluent®)
A monoclonal antibody that lowers LDL‑cholesterol (LDL‑C) by selectively inhibiting PCSK9.

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1. What is it used for?

Condition	Typical indication
Primary hypercholesterolemia	In adults with heterozygous familial hypercholesterolemia (HeFH) or with clinical atherosclerotic cardiovascular disease (ASCVD) when statins (± ezetimibe) can’t achieve LDL‑C goals.
LDL‑C ≥ 70 mg/dL (≥ 1.8 mmol/L)	When statins are tolerated but targets are not reached, or statins are contraindicated.

Approved in the U.S., EU, Canada, many other countries. FDA label: 2015. EMA: 2017.

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2. How does it work?

• Mechanism

  • PCSK9 (proprotein convertase subtilisin/kexin type 9) binds LDL‑receptors (LDLR) on hepatocytes, tagging them for degradation.
  • Alirocumab binds circulating PCSK9, preventing it from interacting with LDLR.
  • More LDLR remain on hepatocyte surfaces → increased clearance of LDL‑C from bloodstream.

• Effect

  • Average LDL‑C reduction: ~50‑60 % from baseline when added to maximally tolerated statin therapy.
  • Can further reduce LDL‑C when statins are not tolerated or contraindicated.

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3. Dosing & Administration

Dose	Frequency	Typical patient weight
75 mg	Every 2 weeks	≤ 75 kg
150 mg	Every 2 weeks	> 75 kg
150 mg	Once a month	≥ 120 kg or if patient prefers less frequent dosing

• Route: Subcutaneous injection (self‑injection or healthcare‑provider–administered).
• Injection sites: Abdomen, thigh, or upper arm. Rotate sites.
• Timing: Can be given with or without food; if given with a statin, space doses by ≥ 2 weeks to reduce injection‑site reaction risk.

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4. Common Side Effects

Symptom	Frequency	Typical management
Injection‑site reactions (pain, erythema, induration)	5‑10 %	Warm compress, oral antihistamine, change site
Upper respiratory tract infection	3‑5 %	Symptomatic treatment
Headache	< 5 %	OTC analgesic
Musculoskeletal pain	< 5 %	NSAIDs if needed
Rare: hypersensitivity, anaphylaxis	< 1 %	Stop infusion, treat per anaphylaxis protocol

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5. Serious/Contraindications

• Hypersensitivity to alirocumab, humanized monoclonal antibodies, or any component.
• Active, untreated hepatitis B or C (no evidence of increased risk but monitoring advised).
• Pregnancy: Animal studies showed fetal harm; no human data; use only if clearly needed and pregnancy is ruled out.
• Breastfeeding: Not recommended (unknown excretion into milk).

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6. Drug Interactions

• Statins: Co‑administration is standard; watch for statin‑related myopathy.
• Ezetimibe: Safe to combine.
• Anticoagulants: No direct interaction.
• Vaccines: Live‑attenuated vaccines should be avoided during infusion (rare).
• Other monoclonal antibodies: No known additive risk.

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7. Monitoring

Parameter	Frequency	Why
LDL‑C, HDL‑C, Total cholesterol	Every 4–12 weeks	Assess efficacy & adjust dose
Creatine kinase (CK)	At baseline & if muscle symptoms	Monitor for statin‑related myopathy
Liver enzymes	Baseline & periodically	Monitor hepatotoxicity (rare)
Injection‑site examination	Each visit	Detect local reactions

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8. Special Populations

Group	Notes
Renal impairment	No dose adjustment needed.
Hepatic impairment	No dose adjustment but monitor liver enzymes.
Children / Adolescents	Not approved; clinical trials ongoing.
Pregnancy/Breastfeeding	Use only if benefits outweigh risks; discuss with healthcare provider.

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9. Cost & Insurance

• Retail price (US): ~$1,400–$1,500 per 150 mg vial (often 2 vials/month).
• Insurance: Most major plans cover; prior authorization usually required. Check formulary.

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10. Practical Tips for Patients

1. Injection technique
   • Clean the site with alcohol, wait 30 s.
   • Pinch skin, insert needle at 45–90° angle, inject slowly.
   • Remove needle, apply light pressure.
2. Storage
   • Store in a refrigerator (2–8 °C) or at room temperature (up to 30 °C) if unopened.
   • Do not freeze.
3. Adherence
   • Set a calendar reminder.
   • Keep injection supplies in a discreet pocket or bag.

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11. Frequently Asked Questions

Question	Short Answer
Does it replace statins?	No, it’s an adjunct; used when statins alone are insufficient or not tolerated.
Can I stop it if I feel fine?	No. Abrupt discontinuation may raise LDL‑C quickly; discuss with provider.
Are there any diet restrictions?	No specific restrictions, but maintain a healthy diet to support lipid goals.
Is it safe during a viral infection?	Generally safe; avoid live vaccines while on therapy.

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12. Where to Learn More

• FDA label: FDA.gov – Praluent
• EMA Summary of Product Characteristics: [EMA website]
• National Lipid Association Guidelines: [NLA.org]
• Patient support program: Praluent® Patient Support

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Bottom line:
Alirocumab is a highly effective PCSK9 inhibitor that helps patients with high LDL‑C levels lower their cholesterol when statins alone aren’t enough. It’s administered subcutaneously every 1–2 weeks, is generally well‑tolerated, but requires regular monitoring and adherence to dosing schedules. Always talk to your healthcare provider about whether this therapy is right for you and how to manage any potential side effects.