FDA-filed SPL labeling · retrieved through openFDA

Alemtuzumab Injection (Chronic Lymphocytic Leukemia)

Alemtuzumab (Lemtrada) is a targeted antibody infusion used to treat relapsing forms of multiple sclerosis in adults when other MS medications haven't worked well enough.

Brand names CampathLemtrada
Drug class ⓘ Cd52-directed Cytolytic Antibody
Rx Route Intravenous
Dr. Brian Staiger, PharmD, BCPS
Reviewed by Last reviewed Jul 10, 2026
🧬 Where this information comes from Click to expand

The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 1 clinical label set within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →

At a glance
Linked label effectiveNov 3, 2025
AvailabilityRx
Boxed warningYes
How we combine label and product data →
✓No current FDA shortage listed · checked Oct 1, 2026
💊
HelloPharmacist Editorial Team Bottom Line
Alemtuzumab is a powerful MS medication reserved for people who haven't responded to other treatments — it can meaningfully reduce relapses, but it comes with serious risks that require ongoing monitoring for years. You'll need monthly lab tests and regular check-ins with your care team long after your infusions are done. The key is staying engaged with follow-up so any problems are caught early.
How we write & review this content — our editorial policy →
⚠️ FDA Boxed Warning — the FDA’s strongest safety alert ▾

This drug carries a serious FDA Boxed Warning — the strongest warning possible.

Alemtuzumab can cause serious, sometimes fatal autoimmune reactions — meaning the immune system turns against the body. This includes immune thrombocytopenia (dangerously low platelets that cause uncontrolled bleeding) and a type of kidney disease called anti-glomerular basement membrane disease. Blood and urine must be monitored every month for up to 4 years after the last dose.

It can also cause life-threatening infusion reactions (like severe allergic reactions) and has been linked to stroke — including within just 3 days of an infusion. Get emergency help immediately if you have any sudden stroke symptoms such as numbness, weakness, or trouble speaking. Additionally, there is an increased risk of certain cancers, including thyroid cancer, melanoma, and lymphoma. Yearly skin exams are required. Because of all these risks, this medication is only available through a restricted program (REMS).

Read the full warning on DailyMed →

📖 Alemtuzumab Injection (Chronic Lymphocytic Leukemia): Patient Information Guide

A plain-language walkthrough of Alemtuzumab Injection (Chronic Lymphocytic Leukemia) — what it treats, how it works, how it’s taken, side effects, warnings and interactions. Tap any section to expand it.

What Alemtuzumab Injection (Chronic Lymphocytic Leukemia) is used for

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Alemtuzumab (Lemtrada) treats relapsing forms of multiple sclerosis (MS) in adults. It is generally used only after other MS medications have not worked well enough.

  • Relapsing-remitting MS — the most common form, with episodes of new or worsening symptoms followed by periods of recovery
  • Active secondary progressive MS — a later stage where disability gradually worsens, but relapses are still occurring

Not recommended for clinically isolated syndrome (CIS), a first MS-like episode, because the risks outweigh the benefits at that stage.

How Alemtuzumab Injection (Chronic Lymphocytic Leukemia) works

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Alemtuzumab is a monoclonal antibody — a precisely engineered protein — that targets a molecule called CD52 found on the surface of T and B lymphocytes (immune cells central to MS inflammation), as well as natural killer cells, monocytes, and macrophages. When it locks onto these cells, it signals the immune system to destroy them through two processes: antibody-dependent cellular cytolysis and complement-mediated lysis (both are ways the body dismantles and clears those tagged cells). The result is a dramatic reduction in the circulating immune cells responsible for attacking the nervous system in MS.

Because it depletes the immune system so significantly, it also opens the door to serious risks — which is why such intensive monitoring is required.

How Alemtuzumab Injection (Chronic Lymphocytic Leukemia) is taken (dosage)

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Alemtuzumab is given as an IV infusion in a clinical or hospital setting — not at home. Treatment is delivered in courses separated by at least 12 months.

  • First course: infusions on 5 consecutive days
  • Second course: infusions on 3 consecutive days, given 12 months after the first
  • Additional courses: may be given on 3 consecutive days, at least 12 months after the previous course, if your doctor determines they are needed
  • Each infusion takes about 4 hours; you are monitored for at least 2 hours after each one
  • You will receive corticosteroids before the first 3 days of each course, and antiviral medication starting on the first day and continuing for at least 2 months after treatment

Follow your prescriber's instructions exactly. Do not adjust or skip treatments on your own.

Alemtuzumab Injection (Chronic Lymphocytic Leukemia) side effects in detail

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The most commonly reported side effects include:

  • Rash, itching (pruritus), or hives (urticaria)
  • Headache and dizziness
  • Fever and fatigue
  • Nausea, vomiting, diarrhea, or abdominal pain
  • Stuffy nose, sore throat, and upper respiratory infections
  • Urinary tract infections
  • Herpes viral infections
  • Thyroid gland problems

More serious reactions — including stroke, severe autoimmune conditions, anaphylaxis (severe allergic reaction), and certain cancers — require immediate medical attention. Call your doctor or get emergency help right away if you notice unusual bleeding, stroke symptoms, signs of kidney problems, or any sudden worsening of your health.

Alemtuzumab Injection (Chronic Lymphocytic Leukemia) warnings and precautions

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The most critical risks are autoimmune reactions, infusion reactions, stroke, and cancer. Alemtuzumab can cause the immune system to attack the body's own organs — including the blood, kidneys, thyroid, liver, and brain. These reactions can be fatal. Monthly blood and urine monitoring is required for up to 4 years after the last dose, and thyroid function must be checked every 3 months during that period.

  • Stroke: has occurred within 3 days of infusion — get emergency care immediately for any sudden stroke symptoms
  • Infusion reactions: can be severe or life-threatening; infusions must be given where emergency care is available
  • Immune thrombocytopenia: dangerously low platelets leading to uncontrolled bleeding
  • Kidney disease: including anti-glomerular basement membrane disease
  • Thyroid disorders: very common — can develop months or years after treatment
  • Cancer risk: increased risk of thyroid cancer, melanoma, and lymphoma; annual skin exams required
  • Serious infections: including herpes, fungal, and others due to immune suppression; live vaccines must be avoided after treatment
  • Autoimmune hepatitis, colitis, encephalitis, and other rare but serious conditions have also been reported

Alemtuzumab Injection (Chronic Lymphocytic Leukemia) interactions: what it interacts with

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Because alemtuzumab profoundly suppresses the immune system, certain drugs, vaccines, and conditions can create dangerous interactions:

  • Live vaccines — must not be given after treatment; the weakened immune system cannot safely handle live pathogens and infection could result
  • HIV infection — alemtuzumab is contraindicated; it further depletes CD4+ immune cells that people with HIV already lack, increasing infection risk severely
  • Active infections — treatment is contraindicated during any active infection; starting alemtuzumab while infected could be life-threatening

This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.

Before taking Alemtuzumab Injection (Chronic Lymphocytic Leukemia)

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  • HIV positive: do not use — it is contraindicated
  • Active infection: treatment must wait until the infection is fully resolved
  • Pregnancy: may cause fetal harm, including embryo death in animal studies; placental transfer of thyroid antibodies has caused serious disease in newborns — avoid becoming pregnant during and for at least 4 months after each treatment course
  • Women of childbearing potential: use effective contraception during treatment and for 4 months afterward
  • No varicella (chickenpox) history or vaccine: testing and possible vaccination required at least 6 weeks before starting
  • Tuberculosis exposure: screening required before treatment
  • Upcoming vaccines needed: complete all necessary immunizations at least 6 weeks before starting — live vaccines cannot be given after treatment
  • Listeria risk: avoid high-risk foods (such as unpasteurized cheeses and deli meats) — your doctor will advise you on this before treatment

Alemtuzumab Injection (Chronic Lymphocytic Leukemia) overdose: if you take too much

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There have been reports of accidental overdose in MS patients who received higher-than-intended doses in a single infusion, causing reactions including headache, rash, low blood pressure, and rapid heart rate. Higher doses may intensify or prolong infusion reactions and immune suppression. There is no known antidote — treatment would focus on managing symptoms, and immediate medical attention is essential.

Pharmacodynamics: what Alemtuzumab Injection (Chronic Lymphocytic Leukemia) does in the body

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After each course of alemtuzumab, circulating T and B lymphocytes drop sharply — hitting their lowest levels about one month after treatment. B cells typically recover within 6 months, but T cells recover much more slowly and often remain below normal levels for at least 12 months. About half of patients still have below-normal CD4+ T cell counts (key infection-fighting cells) at 30 months after treatment. During the first infusion, heart rate rises by roughly 22–26 beats per minute for at least 2 hours, though this effect is not seen with later infusions in the same course.

Pharmacokinetics: how your body processes Alemtuzumab Injection (Chronic Lymphocytic Leukemia)

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Alemtuzumab is given by IV infusion and stays largely in the blood and the fluid surrounding body tissues. Drug levels build up with each consecutive infusion within a course, peaking after the last infusion of that course. The elimination half-life (the time it takes for the body to clear half the drug) is approximately 2 weeks — consistent across treatment courses. Blood levels generally become undetectable within a few weeks after a course ends, though the drug's effects on immune cells last much longer.

How to store Alemtuzumab Injection (Chronic Lymphocytic Leukemia)

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Store LEMTRADA vials at 2°C to 8°C (36°F to 46°F). Do not freeze or shake. Store in original carton to protect from light.

📄 Written from Alemtuzumab Injection (Chronic Lymphocytic Leukemia)’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Every point is grounded in that labeling — nothing is invented. How we use AI →

70

Supplements & herbs that interact with Alemtuzumab Injection (Chronic Lymphocytic Leukemia)

70 supplements and herbal products have documented interactions with Alemtuzumab Injection (Chronic Lymphocytic Leukemia) in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.

Severity mix
  • Major · 1
  • Moderate · 59
  • Minor · 10
ACTIVATED CHARCOAL Major ACTIVE HEXOSE CORRELATED COMPOUND (AHCC) Moderate ALFALFA Moderate AMERICAN GINSENG Moderate ANDROGRAPHIS Moderate ASHWAGANDHA Moderate ASTRAGALUS Moderate BEE VENOM Moderate +62 more
Every supplement checked against Alemtuzumab Injection (Chronic Lymphocytic Leukemia) — ranked by severity The full interaction hub: 1 major · 59 moderate · 10 minor · every one linked to its full report. Check Alemtuzumab Injection (Chronic Lymphocytic Leukemia) against your exact supplements

Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.

🩺 Alemtuzumab Injection (Chronic Lymphocytic Leukemia): pharmacist answers to common questions

Quick, plain-English answers to the questions patients ask most about Alemtuzumab Injection (Chronic Lymphocytic Leukemia) — the kind of thing our pharmacy team would talk through with you at the counter.

Why is my doctor recommending this medication when there are other MS treatments out there?

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Alemtuzumab is generally reserved for people whose MS hasn't responded well enough to at least two other medications. It's a more aggressive treatment that can make a real difference in reducing relapses, but it comes with significant risks — so it's not a first choice. If your doctor is recommending it, they've weighed the risks against the fact that your MS needs stronger intervention.

What should I expect on the days I get the infusion?

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Each infusion takes about 4 hours, and you'll need to stay for at least 2 more hours of monitoring afterward. Before the infusion, you'll receive a corticosteroid medication to help reduce reactions. You may experience side effects like headache, rash, fever, nausea, or flushing during or shortly after the infusion. The clinic is set up to handle any reactions right away — you won't be going through this alone.

Why do I need blood tests every single month for four years?

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Alemtuzumab can trigger the immune system to attack your own body — your blood, kidneys, thyroid, liver, and other organs — sometimes months or even years after treatment. Monthly blood and urine tests are the early-warning system that catches these problems before they become serious or life-threatening. It feels like a lot, but this monitoring is truly one of the most important parts of staying safe on this medication.

I had a headache and felt my heart racing during the infusion — is that normal?

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Yes, a temporary increase in heart rate during the first infusion is a known effect, and headache is one of the most commonly reported side effects. The clinical team monitors you closely during and after the infusion precisely for this reason. That said, always tell the nurse or doctor right away if anything feels wrong — some infusion reactions can be serious and need prompt treatment.

I'm thinking about getting pregnant in the next couple of years — how does this affect that?

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This is really important to discuss with your doctor before starting. You should use reliable contraception during treatment and for at least 4 months after each course. The drug can cause fetal harm, and it can also trigger thyroid problems that persist long after treatment — untreated thyroid disease in pregnancy carries its own risks for both you and your baby. Your care team will monitor your thyroid closely and help you plan safely if pregnancy is on your horizon.

What stroke warning signs should I watch for after my infusion?

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Stroke has been reported within 3 days of an alemtuzumab infusion. If you suddenly experience face drooping, arm weakness, trouble speaking, vision changes, a severe headache unlike any you've had before, or numbness on one side of your body — call 911 or get to an emergency room immediately. Don't wait to see if it passes. This is one warning sign where every minute matters.

Is Alemtuzumab Injection (Chronic Lymphocytic Leukemia) available over the counter?

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Alemtuzumab Injection (Chronic Lymphocytic Leukemia) is dispensed by prescription according to its FDA labeling, so it isn't sold over the counter. Your prescriber and pharmacist will determine if it's appropriate for you.

💬 Answers drafted from Alemtuzumab Injection (Chronic Lymphocytic Leukemia)’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Grounded in that labeling — nothing is made up. How we use AI →

🧰 More about Alemtuzumab Injection (Chronic Lymphocytic Leukemia) on HelloPharmacist

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RxNorm Concept Web — From Ingredient to Every Form and Strength

This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.

Ingredient (IN) Alemtuzumab Injection (Chronic Lymphocytic Leukemia) RxCUI 117055 1 dose form · 2 strengths

Look up RxCUI 117055 in the RxCUI Atlas →

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🏷️ Alemtuzumab Injection (Chronic Lymphocytic Leukemia) brand names

Campath Lemtrada

Alemtuzumab Injection (Chronic Lymphocytic Leukemia) drug class (RxNorm)

Alemtuzumab Injection (Chronic Lymphocytic Leukemia) belongs to the CD52-directed Cytolytic Antibody class.

Pharmacologic class CD52-directed Cytolytic Antibody
Drug family (ATC) Monoclonal antibodies
How it works CD52-directed Antibody Interactions

Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.

🔬 Sources for this Alemtuzumab Injection (Chronic Lymphocytic Leukemia) page

Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.

📄
FDA-filed drug labels (SPL) Uses, dosing, warnings & side effects from SPL records retrieved through openFDA; the linked representative set can be verified on DailyMed. ✓ Linked label effective Nov 3, 2025
🏭
Forms, brands & labelersAggregated from ingredient-matched FDA National Drug Code Directory product records for Alemtuzumab Injection (Chronic Lymphocytic Leukemia).
📈
Real-world reportsThe FDA Adverse Event Reporting System (FAERS), served through openFDA.
🚨
Recalls & shortagesopenFDA drug-enforcement reports and the FDA drug-shortage database.
🧾 Clinical label set — FDA-filed SPL labels retained for Alemtuzumab Injection (Chronic Lymphocytic Leukemia) after exact ingredient or ingredient-combination matching and applicable route/form matching
Clinical labels in scope
1
Linked representative label ⓘ
Genzyme Corporation
Linked label effective
Nov 3, 2025
Composite sections available
23
Linked SPL Set ID
6236b0bc-82e9-4447-9a78-f57d94770269
Linked SPL Document ID
e9b870b2-1ea2-433f-991a-721c3cf582b1
Open the linked representative label on DailyMed ↗

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