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.
🧬 Where this information comes from
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 →
Alemtuzumab (Lemtrada) is a lab-made antibody infusion for relapsing multiple sclerosis (MS) that latches onto CD52, a protein on T and B immune cells, and triggers their destruction; it can meaningfully cut relapses but is reserved for people who have tried at least two other MS medicines. Infusion days often bring rash or flushing, headache, fever and nausea, and thyroid problems and herpes infections are common later. Its boxed warning covers serious autoimmune conditions (such as dangerously low platelets and kidney disease), infusion reactions, stroke and cancers, so the monthly blood and urine tests that run for 4 years after the last dose are the part you cannot skip.
Clinical pearls
- Sudden numbness, weakness, trouble speaking or a severe headache within 3 days of an infusion means calling emergency services.
- Get any needed vaccines, including chickenpox, at least 6 weeks before the first course, because live vaccines are off-limits afterward.
- Take the antiviral medicine prescribed alongside the infusions faithfully, since herpes infections are a common side effect.
- Use effective contraception during treatment and for at least 4 months after each course, and tell your team before planning pregnancy.
⚠️ 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).
Patient Information Guide A plain-language walkthrough of Alemtuzumab Injection (Chronic Lymphocytic Leukemia), written from its FDA label.
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.
Alemtuzumab Injection (Chronic Lymphocytic Leukemia) 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.
Dosing details from the FDA-approved label
From the Alemtuzumab Injection (Chronic Lymphocytic Leukemia) prescribing information (“Dosage and Administration”). Doses are set by your prescriber for your product, condition, kidney function and age — never change a dose on your own.
Read the label’s full dosing text
2 DOSAGE AND ADMINISTRATION Baseline laboratory tests are required prior to treatment. ( 2.1 ) Administer LEMTRADA by intravenous infusion over 4 hours for 2 or more treatment courses: Initial treatment of 2 courses: First course: 12 mg/day on 5 consecutive days. ( 2.3 ) Second course: 12 mg/day on 3 consecutive days 12 months after first treatment course. ( 2.3 ) Subsequent treatment courses of 12 mg per day on 3 consecutive days (36 mg total dose) may be administered, as needed, at least 12 months after the last dose of any prior treatment course. ( 2.3 ) Premedicate with corticosteroids prior to LEMTRADA infusion for the first 3 days of each treatment course. ( 2.2 ) Administer antiviral agents for herpetic prophylaxis starting on the first day of LEMTRADA dosing and continuing for a minimum of two months after completion of LEMTRADA dosing or until CD4+ lymphocyte count is more than 200 cells per microliter, whichever occurs later. ( 2.2 ) Must be diluted prior to administration. ( 2.4 ) 2.1 Testing and Procedures Prior to Treatment Baseline laboratory tests are required prior to treatment with LEMTRADA [see Dosage and Administration (2.6) ] . In addition, prior to starting treatment with LEMTRADA [see Warnings and Precautions (5.15) ] : complete any necessary immunizations at least 6 weeks prior to treatment. determine whether patients have a history of varicella or have been vaccinated for varicella zoster virus (VZV). If not, test the patient for antibodies to VZV and consider vaccination for those who are antibody-negative. Postpone treatment with LEMTRADA until 6 weeks after VZV vaccination. perform tuberculosis screening according to local guidelines. instruct patients to avoid potential sources of Listeria monocytogenes. 2.2 Recommended Premedication and Concomitant Medication Corticosteroids Premedicate patients with high dose corticosteroids (1,000 mg methylprednisolone or equivalent) immediately prior to LEMTRADA infusion and for the first 3 days of each treatment course [see Warnings and Precautions (5.2) ] .
Excerpted — the section continues on the label. Read the full Dosage and Administration section on DailyMed →
Alemtuzumab Injection (Chronic Lymphocytic Leukemia) Side Effects
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The most commonly reported side effects include:
Common side effects
- Rash or skin flushing
- Headache
- Fever (pyrexia)
- Nausea or vomiting
- Fatigue
- Urinary tract infection
- Herpes viral infections
- Thyroid gland problems
- Rash, itching (pruritus), or hives (urticaria)
- Headache and dizziness
- Nausea, vomiting, diarrhea, or abdominal pain
- Stuffy nose, sore throat, and upper respiratory infections
When to get medical help
- Signs of stroke — sudden numbness, weakness, trouble speaking, or severe headache — seek emergency care immediately, especially within 3 days of an infusion
- Unusual bleeding or bruising — could signal immune thrombocytopenia (dangerously low platelets)
- Blood in urine, swelling, or sharp drop in kidney function — possible kidney (glomerular) disease
- Signs of serious infection — high fever, chills, painful urination, or cough that doesn't go away
- Severe infusion reactions — chest tightness, throat swelling, rapid heartbeat, or difficulty breathing during or after infusion
- New or worsening thyroid symptoms — unexplained weight changes, racing heart, feeling too hot or too cold
- Confusion, memory problems, or seizures — could indicate autoimmune encephalitis (brain inflammation)
- Yellowing of skin or eyes, or dark urine — possible autoimmune hepatitis (liver inflammation)
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
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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
Not a complete list. The label covers the interactions the manufacturer studied or reported, and our own interaction database does not cover every medicine either. Bring your full medication list, including vitamins and herbal products, to your pharmacist.
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
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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.
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.
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 the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
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.
- Major · 1
- Moderate · 59
- Minor · 10
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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What should I expect on the days I get the infusion?
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Why do I need blood tests every single month for four years?
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I had a headache and felt my heart racing during the infusion — is that normal?
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I'm thinking about getting pregnant in the next couple of years — how does this affect that?
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What stroke warning signs should I watch for after my infusion?
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Is Alemtuzumab Injection (Chronic Lymphocytic Leukemia) available over the counter?
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When was Alemtuzumab Injection (Chronic Lymphocytic Leukemia) first available?
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Answers drafted from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
More About Alemtuzumab Injection (Chronic Lymphocytic Leukemia) on HelloPharmacist
Alemtuzumab Injection (Chronic Lymphocytic Leukemia) on the U.S. Market: Products, Makers and Brands
How Alemtuzumab Injection (Chronic Lymphocytic Leukemia) appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.
The FDA lists Alemtuzumab Injection (Chronic Lymphocytic Leukemia) products; the earliest marketing or approval year on record is 2001. Brand names on the directory include Campath, Lemtrada; the rest are generics.
Alemtuzumab Injection (Chronic Lymphocytic Leukemia) Side Effects Reported to the FDA (FAERS)
After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for Alemtuzumab Injection (Chronic Lymphocytic Leukemia) — a signal of what to watch for, not proof the drug caused it.
Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists Alemtuzumab Injection (Chronic Lymphocytic Leukemia) in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.
Alemtuzumab Injection (Chronic Lymphocytic Leukemia) FDA Approval History
How Alemtuzumab Injection (Chronic Lymphocytic Leukemia) went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
Alemtuzumab Injection (Chronic Lymphocytic Leukemia) Recall History
A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.
The FDA’s enforcement reports list no Alemtuzumab recalls since July 2021.
✅No Alemtuzumab recalls on record since July 2021Source: FDA enforcement (recall) reports, via openFDA; our copy was last updated Oct 8, 2026.
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.
RxCUI 117055 1 dose form · 2 strengths
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Dose form (SCDF) Injection RxCUI 1656629No current FDA listingClinical drug / strength (SCD) 1 ML alemtuzumab 30 MG/MLRxCUI 8282651.2 ML alemtuzumab 10 MG/MLRxCUI 1594658
Look up RxCUI 117055 in the RxCUI Atlas →
RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.
Alemtuzumab Injection (Chronic Lymphocytic Leukemia) Supply and Shortage Status
Whether Alemtuzumab Injection (Chronic Lymphocytic Leukemia) is in short supply in the U.S. right now, plus any shortage history the FDA has on record. A shortage usually reflects a manufacturing or demand issue — not a safety problem with the drug.
Source: openFDA, from the FDA Drug Shortages database.
Alemtuzumab Injection (Chronic Lymphocytic Leukemia) Brand Names
Alemtuzumab Injection (Chronic Lymphocytic Leukemia) is sold under 2 brand names in the FDA directory — Campath, Lemtrada. A brand and its generic contain the same active ingredient; the brand name belongs to one company's product.
Alemtuzumab Injection (Chronic Lymphocytic Leukemia) Drug Class (RxNorm)
Alemtuzumab Injection (Chronic Lymphocytic Leukemia) belongs to the CD52-directed Cytolytic Antibody class.
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.
How this page is built
HelloPharmacist combines public FDA and NLM records and does not author the underlying clinical facts. The plain-language sections are written with AI from the FDA-approved label text and reviewed by our pharmacy team before publication. Genzyme Corporation is the representative DailyMed label linked for verification and dates. This is general education, not medical advice: always talk to your doctor or pharmacist about your own medicines. How we build and review drug pages →