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Alemtuzumab Side Effects

Medically reviewed by Last updated on Jul 30, 2023.

Applies to alemtuzumab: intravenous solution.


Intravenous route (Solution)

Cytopenias, Infusion-related Reactions, and InfectionsSerious, including fatal, cytopenias, infusion-related reactions, and infections can occur.Limit doses to 30 mg (single) and 90 mg (cumulative weekly); higher doses increase risk of pancytopenia.Escalate dose gradually and monitor patients during infusion. Withhold therapy for Grade 3 or 4 infusion-related reactions.Administer prophylaxis against Pneumocystis jirovecii pneumonia (PCP) and herpes virus infections.

Intravenous route (Solution)

Autoimmunity, Infusion Reactions, Stroke, and MalignanciesAlemtuzumab causes serious, sometimes fatal, autoimmune conditions such as immune thrombocytopenia and anti-glomerular basement membrane disease. Monitor complete blood counts with differential, serum creatinine levels, and urinalysis with urine cell counts before starting treatment and then at monthly intervals until 48 months after the last does of alemtuzumab.Alemtuzumab causes serious and life-threatening infusion reactions. Alemtuzumab must be administered in a setting with appropriate equipment and personnel to manage anaphylaxis or serious infusion reactions. Monitor patients for two hours after each infusion. Make patients aware that serious infusion reactions can also occur after the 2-hour monitoring period.Serious and life-threatening stroke (including ischemic and hemorrhagic stroke) has been reported within 3 days of alemtuzumab administration. Instruct patients to seek immediate medical attention if symptoms of stroke occur.Alemtuzumab may cause an increased risk of malignancies, including thyroid cancer, melanoma, and lymphoproliferative disorders. Perform baseline and yearly skin exams.Because of the risk of autoimmunity, infusion reactions, and malignancies, alemtuzumab is available only through restricted distribution under a Risk Evaluation Mitigation Strategy (REMS) Program. Call 1-855-676-6326 to enroll in the alemtuzumab REMS program.

Serious side effects of Alemtuzumab

Along with its needed effects, alemtuzumab may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur while taking alemtuzumab:

More common

Less common


Incidence not known

Other side effects of Alemtuzumab

Some side effects of alemtuzumab may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Less common


For Healthcare Professionals

Applies to alemtuzumab: intravenous solution.


Very common (10% or more): Lymphopenia (97%), neutropenia (77%), anemia (76%), thrombocytopenia (71%), granulocytopenia

Common (1% to 10%): Decrease in CD4 lymphocytes, decrease in CD8 lymphocytes, decrease in T-lymphocyte count, febrile neutropenia, pancytopenia, leukopenia, lymphopenia, purpura

Uncommon (0.1% to 1%): Aplasia bone marrow, disseminated intravascular coagulation, hemolytic anemia, decreased haptoglobin, bone marrow depression, hematology test abnormal[Ref]


Very common (10% or more): Immunogenicity (up to 83%), herpes viral infection (16%), fungal infection (13%), sepsis, cytomegalovirus infection, cytomegalovirus


Common (1% to 10%): Influenza, neutropenic fever

Uncommon (0.1% to 1%): Sepsis, staphylococcal bacteremia, tuberculosis, beta hemolytic streptococcal infections, candidiasis, genital candidiasis, body tinea

Very rare (less than 0.01%): Immune thrombocytopenia

Frequency not reported: Autoimmunity[Ref]


Very common (10% or more): Nasopharyngitis (25%), upper respiratory tract infection (16%), sinusitis (11%), pneumonia

Common (1% to 10%): Cough, dyspnea, bronchitis, chest discomfort, epistaxis, hypoxia, hemoptysis, bronchospasm

Uncommon (0.1% to 1%): Stridor, throat tightness, pulmonary infiltration, pleural effusion, breath sounds decreased, respiratory disorder

Frequency not reported: Respiratory alkalosis[Ref]


Very common (10% or more): Nausea (21%), diarrhea (12%), oropharyngeal pain (11%), abdominal pain (10%), vomiting (10%)

Common (1% to 10%): Dyspepsia, gastrointestinal hemorrhage, ulcerative stomatitis, stomatitis, gastroenteritis, tongue ulceration, gingivitis, hiccup, eructation, dyspepsia, constipation, flatulence, oral candidiasis

Uncommon (0.1% to 1%): Gingival bleeding, dry mouth, paralytic ileus, oral discomfort

Frequency not reported: Duodenal ulcer, intestinal perforation, melena, peptic ulcer, pseudomembranous colitis, colitis, pancreatitis, peritonitis[Ref]

Nervous system

Very common (10% or more): Headache (52%), insomnia (16%), paresthesia (10%), dizziness (10%)

Common (1% to 10%): Dysgeusia, vertigo, tremor, paresthesia, hypoesthesia, hyperkinesia, taste loss

Uncommon (0.1% to 1%): Syncope, abnormal gait, dystonia, hyperesthesia, neuropathy, taste perversion[Ref]


Very common (10% or more): Hypotension, hypertension

Common (1% to 10%): Tachycardia, peripheral edema, vasospasm

Uncommon (0.1% to 1%): Cardiac arrest, myocardial infarction, atrial fibrillation, supraventricular tachycardia, arrhythmia, bradycardia, abnormal ECG, peripheral ischemia, cyanosis, orthostatic hypotension, hot flush

Frequency not reported: Congestive heart failure, cardiomyopathy, decreased ejection fraction in non-MS patients previously treated with potentially cardiotoxic agents[Ref]


Very common (10% or more): Arthralgia (12%), pain in extremity (12%), back pain (12%)

Common (1% to 10%): Chills, muscular weakness, muscle spasms, myalgia, neck pain, arthralgia, skeletal pain, back pain

Uncommon (0.1% to 1%): Leg pain, hypertonia, muscle spasms

Frequency not reported: Arthritis or worsening arthritis, bone fracture, myositis, muscle atrophy, osteomyelitis, polymyositis, skeletal pain[Ref]


Very common (10% or more): Rash (53%), urticaria (16%), pruritus (14%)

Common (1% to 10%): Dermatitis, erythema, hyperhidrosis, bullous eruption, erythematous rash

Uncommon (0.1% to 1%): Maculopapular rash, skin disorder[Ref]


Very common (10% or more): Thyroid gland disorders (13%)[Ref]


Frequency not reported: Hyperbilirubinemia, hepatic failure, hepatocellular damage, hypoalbuminemia, biliary pain[Ref]


Very common (10% or more): Anorexia

Common (1% to 10%): hyponatremia, hypocalcemia, weight decrease, dehydration, thirst

Uncommon (0.1% to 1%): Hypokalemia, diabetes mellitus aggravated

Frequency not reported: Thyroid disorder, fluid overload[Ref]


Frequency not reported: Malignancies (e.g., malignant lymphoma, malignant testicular neoplasm, prostatic cancer, plasma cell dyscrasias, secondary leukemia, squamous cell carcinoma)[Ref]


Very common (10% or more): Urinary tract infection (19%)

Common (1% to 10%): Blood in urine, abnormal uterine bleeding

Uncommon (0.1% to 1%): Impotence, urinary incontinence, urine flow decreased, polyuria, cystitis

Frequency not reported: Cervical dysplasia[Ref]


Very common (10% or more): Pyrexia (29%), fatigue (18%), flushing (10%)

Common (1% to 10%): Asthenia[Ref]


Uncommon (0.1% to 1%): Renal function abnormal

Frequency not reported: Acute renal failure[Ref]


Common (1% to 10%): Conjunctivitis

Uncommon (0.1% to 1%): Endophthalmitis[Ref]


Uncommon (0.1% to 1%): Allergic reaction

Frequency not reported: Anaphylactoid reaction[Ref]


Uncommon (0.1% to 1%): Infusion site bruising, infusion site dermatitis, infusion site pain

Frequency not reported: Infusion reactions (e.g., anaphylaxis, angioedema, bronchospasm, hypotension, chest pain, bradycardia, tachycardia (including atrial fibrillation), hypoxia, syncope, acute respiratory distress syndrome, respiratory arrest, myocardial infarction, acute cardiac insufficiency, cardiac arrest, transient neurologic symptoms, hypertension, headache, pyrexia, rash, nausea, urticaria, pruritus, insomnia, chills, flushing, fatigue, dyspnea, pulmonary infiltrates, dysgeusia, dyspepsia, dizziness, pain)[Ref]

Frequently asked questions


1. Product Information. Campath (alemtuzumab). Berlex Laboratories. 2001;PROD.

2. Cerner Multum, Inc. UK Summary of Product Characteristics.

3. Cerner Multum, Inc. Australian Product Information.

4. Poynton CH, Mort D, Maughan TS. Adverse reactions to Campath-1H monoclonal antibody [letter; comment]. Lancet. 1993;341:1037.

5. Rai KR, Freter CE, Mercier RJ, et al. Alemtuzumab in previously treated chronic lymphocytic leukemia patients who also had received fludarabine. J Clin Oncol. 2002;20:3891-7.

6. Ghobrial IM, Otteman LA, White WL. An EBV-positive lymphoproliferative disorder after therapy with alemtuzumab. N Engl J Med. 2003;349:2570-2; discussion 2570-2.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.