Home Drug Guide Ofatumumab

Drug Guide

Generic Name

Ofatumumab

Brand Names Arzerra, Kesimpta

Classification

Therapeutic: Antineoplastic and immunomodulating agent

Pharmacological: Anti-CD20 monoclonal antibody

FDA Approved Indications

  • Chronic lymphocytic leukemia (Arzerra)
  • Multiple sclerosis (Kesimpta)

Mechanism of Action

Ofatumumab binds selectively to the CD20 antigen on B cells, leading to B cell depletion through complement-dependent cytotoxicity, antibody-dependent cellular cytotoxicity, and apoptosis.

Dosage and Administration

Adult: For CLL: 300 mg IV initially, then 1,000 mg IV weekly for 4 weeks, then maintenance doses as prescribed. For MS: 20 mg subcutaneously monthly after initial loading dose.

Pediatric: Not approved for pediatric use.

Geriatric: Adjust dose based on tolerability and renal function, with careful monitoring.

Renal Impairment: Adjust dosing as needed, based on renal function.

Hepatic Impairment: No specific adjustments recommended.

Pharmacokinetics

Absorption: Subcutaneous route provides steady absorption; IV provides immediate bioavailability.

Distribution: Wide distribution including lymphoid tissues.

Metabolism: Metabolized via proteolytic degradation into peptides and amino acids.

Excretion: Excreted via proteolytic catabolism.

Half Life: Approximately 24 days.

Contraindications

  • Active infections
  • Hypersensitivity to ofatumumab

Precautions

  • Immunosuppression increasing risk of infections, including hepatitis B reactivation, progressive multifocal leukoencephalopathy (PML), infusion reactions, cardiopulmonary reactions, hypersensitivity reactions, malignancies, and hematologic toxicity.

Adverse Reactions - Common

  • Injection site reactions (Common)
  • Upper respiratory infections (Common)
  • Headache (Common)

Adverse Reactions - Serious

  • Progressive multifocal leukoencephalopathy (PML) (Rare)
  • Serious infections (Rare)
  • Infusion reactions including hypotension, bronchospasm, hypoxia (Potentially serious)

Drug-Drug Interactions

  • Other immunosuppressants, live vaccines

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Screen for infections, hepatitis B status, and allergies before initiation.

Diagnoses:

  • Risk for infection
  • Impaired tissue integrity due to infusion reactions

Implementation: Monitor for infusion reactions, infections, and signs of hypersensitivity during and after administration.

Evaluation: Assess patient’s response, watch for adverse effects, and ensure infection prevention.

Patient/Family Teaching

  • Report any signs of infection immediately.
  • Avoid live vaccines during treatment.
  • Understand possible side effects and when to seek medical help.

Special Considerations

Black Box Warnings:

  • Progressive multifocal leukoencephalopathy (PML)

Genetic Factors: N/A

Lab Test Interference: May cause false elevation of serum immunoglobulin levels; monitor accordingly.

Overdose Management

Signs/Symptoms: Severe infusion reactions, hypersensitivity, or infection signs.

Treatment: Supportive care, discontinue ofatumumab, and manage symptoms; no specific antidote.

Storage and Handling

Storage: Store vials refrigerated at 2-8°C (36-46°F), protect from light.

Stability: Stable until expiration date when refrigerated.

🛡️ 5 Critical Medication Safety Tips for Nurses

1

Triple-Check High-Risk Medications

Always have another nurse verify insulin, heparin, warfarin, and chemotherapy drugs. These "high-alert" medications cause the most serious errors. Check concentration, dose calculation, and pump settings twice.

2

Know Look-Alike, Sound-Alike Drugs

Common mix-ups: hydromorphone/morphine, Celebrex/Celexa, Zyprexa/Zyrtec. Always use BOTH generic and brand names, read labels twice, and use barcode scanning when available. One wrong letter can be fatal.

3

Assess Before AND After Giving Meds

Check vitals before cardiac meds, pain levels before analgesics, and blood glucose before insulin. Always reassess within 30 minutes to evaluate effectiveness and watch for adverse reactions.

4

Watch for Drug Interactions

Common dangerous combinations: warfarin + aspirin (bleeding), ACE inhibitors + potassium (hyperkalemia), digoxin + diuretics (toxicity). Always check drug interactions before administering new medications.

5

Educate Your Patients

Teach patients medication names, purposes, major side effects, and what to report. Informed patients catch errors and improve compliance. Always encourage questions - an educated patient is a safer patient.

⚡ Remember: When in doubt, don't give it out! It's always safer to double-check than regret later.

⚠️ Medical Disclaimer

This drug guide is for educational purposes only and is NOT intended for clinical use. Always consult current prescribing information, healthcare providers, and institutional protocols before administering any medication. Do not use this information for patient care decisions.