Alemtuzumab Injection (Multiple Sclerosis)
Alemtuzumab (Lemtrada) is a prescription infusion used to treat relapsing forms of multiple sclerosis in adults when other MS drugs haven't worked well enough.
🧬 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 →
⚠️ FDA Boxed Warning — the FDA’s strongest safety alert ▾
Alemtuzumab (Lemtrada) carries the FDA's most serious warning — a Boxed Warning — for four major risks:
- Autoimmune reactions: This drug can cause the immune system to attack the body's own tissues, sometimes fatally. This includes a blood platelet disorder that can cause severe bleeding, and a serious kidney disease. Monthly blood and urine monitoring is required for up to 4 years after your last infusion.
- Serious infusion reactions: Life-threatening allergic reactions can happen during or after the infusion. Every infusion must be given in a facility equipped to manage severe reactions, and you must be monitored for at least 2 hours after each dose. Reactions can also occur after you leave.
- Stroke: Serious strokes — both from blood clots and from bleeding — have been reported within 3 days of receiving this drug. Seek emergency care immediately if you have sudden weakness, face drooping, vision changes, severe headache, or trouble speaking.
- Cancer risk: There is an increased risk of thyroid cancer, melanoma (skin cancer), and certain lymph system cancers. Yearly skin exams are required.
Because of these risks, this drug is only available through a restricted program. Enrollment is required before you can receive it.
📖 Alemtuzumab Injection (Multiple Sclerosis): Patient Information Guide
A plain-language walkthrough of Alemtuzumab Injection (Multiple Sclerosis) — what it treats, how it works, how it’s taken, side effects, warnings and interactions. Tap any section to expand it.
🎯What it's used for▾
Alemtuzumab treats relapsing forms of multiple sclerosis (MS) in adults. It is generally used only after other MS treatments have not worked well enough.
- Relapsing-remitting MS (the most common form, with flare-ups and periods of recovery)
- Active secondary progressive MS (a later stage where disability gradually worsens, but there is still evidence of active relapses)
Not for: Clinically isolated syndrome (a first single MS episode) — the risks outweigh the benefits in that setting.
⚙️How it works▾
Alemtuzumab is a monoclonal antibody — a targeted protein — that attaches to a surface marker called CD52, which sits on T cells, B cells, and several other immune cell types. When it binds to T and B lymphocytes, it signals the body to destroy those cells through two processes: antibody-dependent cellular cytolysis and complement-mediated lysis (essentially, the immune system and a protein cascade both help eliminate the marked cells). By wiping out large numbers of these immune cells, the drug disrupts the immune attacks that damage the brain and spinal cord in MS.
After treatment, immune cell counts gradually recover over months. B cells typically return within about 6 months; T cells recover more slowly and may remain below normal for a year or more. This slow, selective rebuilding of the immune system is believed to be part of how the drug reduces MS activity long-term.
💊How it's taken▾
Alemtuzumab is given as an intravenous (IV) infusion at a qualified medical facility — never at home. Treatment is spread over two initial courses roughly a year apart, with possible additional courses at least 12 months apart if needed.
- First course: once daily for 5 consecutive days
- Second course: once daily for 3 consecutive days, given 12 months after the first
- Additional courses (if needed): 3 consecutive days, at least 12 months after the prior course
- Each infusion takes about 4 hours, followed by at least 2 hours of monitoring at the clinic
- You'll receive a corticosteroid before each of the first 3 infusion days, and an antiviral pill starting on Day 1 of treatment, continuing for at least 2 months after — or until your immune cell count recovers sufficiently
🤒Side effects — in detail▾
The most commonly reported side effects include:
- Rash, hives, or itching
- Headache
- Fever
- Nausea, diarrhea, or vomiting
- Fatigue
- Urinary tract infections
- Herpes viral infections (cold sores, shingles)
- Upper respiratory infections or sinusitis
- Thyroid gland problems
- Joint or back pain, tingling, or dizziness
- Flushing during infusion
Seek emergency medical help right away if you notice signs of a severe allergic infusion reaction (throat swelling, difficulty breathing, severe dizziness), signs of stroke (sudden weakness, slurred speech, severe headache), unusual bleeding or bruising, blood in urine, or confusion and memory changes — these can signal serious, life-threatening complications.
⚠️Warnings & precautions▾
- Autoimmune conditions: Alemtuzumab can cause the immune system to attack the body — including dangerous low platelet counts (bleeding risk), serious kidney disease, thyroid disorders, liver inflammation, and rarer conditions affecting the brain, blood, and colon. Monthly lab monitoring is required for 4 years after your last dose.
- Serious infusion reactions: Potentially fatal allergic reactions can occur during or after each infusion. Every infusion must be given where emergency equipment and trained staff are available. You'll be monitored for 2 hours after each dose, but reactions can still occur after you leave.
- Stroke: Both clot-based and bleeding strokes have been reported within 3 days of infusion. Know the warning signs and call 911 immediately if they occur.
- Cancer risk: There is an increased risk of thyroid cancer, melanoma, and lymphoma-type cancers. Yearly skin and thyroid monitoring is required.
- Infections: The drug significantly reduces immune cells, raising your risk of serious infections including herpes, fungal infections, and progressive multifocal leukoencephalopathy (PML) — a rare but serious brain infection. Live vaccines must be avoided after treatment.
- Restricted availability: This drug is only dispensed through the LEMTRADA REMS (Risk Evaluation and Mitigation Strategy) Program — a special safety program requiring enrollment and ongoing monitoring.
🔀What it interacts with▾
Because alemtuzumab powerfully suppresses the immune system, certain medications and vaccines require special attention:
- Live vaccines: Must not be given after treatment — a weakened immune system cannot safely handle live viral vaccines. Complete all necessary immunizations at least 6 weeks before starting.
- Antiviral medications (e.g., for herpes): Must be taken alongside and after treatment to reduce the risk of serious herpes infections triggered by immune suppression.
- Other immunosuppressant drugs: Combining them with alemtuzumab may dangerously increase infection risk and immune side effects.
- Varicella (chickenpox) vaccine: If needed before treatment, it must be given at least 6 weeks prior to the first infusion.
This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.
📋Before taking it▾
- HIV infection: Alemtuzumab is contraindicated — it must not be used — in anyone with HIV, because it causes prolonged reductions in CD4+ immune cells, which are already depleted in HIV.
- Active infection: Treatment cannot be started while you have any active infection.
- Pregnancy: This drug may harm a developing baby. Animal studies showed embryo death. Thyroid antibodies from the drug can cross the placenta and cause thyroid disease in newborns. Use effective contraception during treatment and for 4 months after each course. Tell your doctor right away if you become pregnant.
- Breastfeeding: Talk to your doctor — it is unknown whether alemtuzumab passes into breast milk.
- Thyroid conditions: This drug frequently causes thyroid disorders; pre-existing thyroid disease requires extra monitoring.
- Hypersensitivity: Do not use if you have ever had a severe allergic reaction to alemtuzumab or any ingredient in the formulation.
- Tuberculosis: Screening is required before starting treatment.
- Chickenpox history or vaccination status: Must be confirmed before starting; unvaccinated patients who lack immunity may need vaccination at least 6 weeks before treatment.
🚑If you take too much▾
There is no known antidote for a alemtuzumab overdose. In two reported cases of accidental higher-than-intended doses, patients experienced headache, rash, and either low blood pressure or a racing heart. Higher doses may increase the severity or duration of infusion reactions and immune effects. If an overdose is suspected, contact your medical team or emergency services immediately.
📡Pharmacodynamics — effects in the body▾
After each treatment course, alemtuzumab causes a rapid and dramatic reduction in circulating T and B lymphocytes. Cell counts are lowest about one month after treatment. B cells typically recover within about 6 months; T cell recovery is slower, often remaining below normal levels at 12 months and beyond — with roughly half of patients still having below-normal CD4+ T cell counts at 30 months. During infusion, the drug can cause a temporary increase in heart rate (about 22–26 beats per minute above baseline), mainly after the first infusion.
🔬Pharmacokinetics — how your body processes it▾
Alemtuzumab is given directly into the bloodstream by IV infusion, so there is no absorption step — it enters circulation immediately. It distributes largely within the blood and the fluid around tissues. The drug is cleared slowly, with an elimination half-life of about 2 weeks, meaning it takes roughly 2 weeks for the body to clear half of the drug. Blood levels are generally undetectable within about 30 days after each treatment course ends.
📦How to store it▾
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 (Multiple Sclerosis)’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 →
🩺 Pharmacist Counseling Corner
Quick, plain-English answers to the questions patients ask most about Alemtuzumab Injection (Multiple Sclerosis) — the kind of thing our pharmacy team would talk through with you at the counter.
Why is this drug only available through a special program? Can't my regular pharmacy dispense it? ▾
Why do I need blood tests every month for four years? That seems like a long time. ▾
What should I do if I feel strange during or after my infusion? ▾
I've heard this drug can cause thyroid problems. What should I watch for at home? ▾
Is it safe to get vaccinated while I'm on this treatment? ▾
Can I get pregnant while taking this medication? ▾
Is Alemtuzumab Injection (Multiple Sclerosis) available over the counter? ▾
💬 Answers drafted from Alemtuzumab Injection (Multiple Sclerosis)’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 →
🧰 Keep exploring
📈 What people report — real-world data (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 (Multiple Sclerosis) — 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 (Multiple Sclerosis) 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.
🏛️ The road to your pharmacy
How Alemtuzumab Injection (Multiple Sclerosis) went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
🚨 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.
Source: openFDA drug enforcement (recall) reports.
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.
📦 Supply & shortage status
Whether Alemtuzumab Injection (Multiple Sclerosis) 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.
🏷️ Sold under these brand names
RxNorm drug class
Alemtuzumab Injection (Multiple Sclerosis) 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.
🔬 Where this comes from
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 we combine label and product data
HelloPharmacist combines public FDA and NLM records; we don’t author the underlying clinical facts. We identified 1 FDA-filed SPL label set within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. The representative label is the starting point for the displayed reference monograph; the 12 largest stored in-scope SPL records, which may include that representative, are compared section by section, and the longest available version of each section is retained. Forms, routes, brands, labelers, product-listed strengths, and product-record counts are aggregated separately from ingredient-matched FDA NDC Directory records; package records listed above are associated with the linked SPL; and the normalized concept hierarchy comes from NLM RxNorm.
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This is general education, not medical advice — always consult your doctor or pharmacist about your medications and any medical condition. For the exact wording of the linked representative label, view that label on DailyMed; some displayed composite sections may come from other in-scope SPL labels. Learn how we use AI and our data sources & update cadence.