omalizumab
Brand: Xolair
Prototype Drug
Drug Class: biologic — anti-IgE monoclonal antibody
Drug Family: biologic
Subclass: anti-IgE humanized monoclonal antibody
Organ Systems: respiratoryimmunology
Mechanism of Action
Binds free serum IgE preventing it from binding FcεRI receptors on mast cells and basophils; reduces high-affinity IgE receptor expression; decreases mast cell/basophil activation.
immunoglobulin E (IgE)
Indications
- moderate-severe allergic asthma (IgE-mediated; baseline IgE 30-700 IU/mL)
- chronic idiopathic urticaria
- nasal polyps
Contraindications
- not for acute bronchospasm
- anaphylaxis history to omalizumab
Adverse Effects
Common
- injection site reactions
- upper respiratory infection
- headache
- nasopharyngitis
Serious
- anaphylaxis (0.2% — delayed onset up to 24h after injection)
- malignancy (signal in some studies)
Pharmacokinetics (ADME)
| Absorption | ~62% SC bioavailability |
| Distribution | serum and tissues |
| Metabolism | proteolytic degradation |
| Excretion | hepatic proteolysis |
| Half-life | 26 days |
| Onset | 7-8 days |
| Peak | 7-14 days |
| Duration | 28 days |
| Protein Binding | <0% |
| Vd | 78 mL/kg |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| other biologics | additive immunosuppression risk | moderate |
Nursing Considerations
- Administer by healthcare provider only (delayed anaphylaxis risk)
- Observe patient 2 hours after first 3 injections and 30 minutes subsequently
- Dose and frequency based on baseline IgE level and body weight
- Clinical response assessed after 16 weeks
- Does not prevent acute attacks — continue controller medications
Clinical Pearls
- Anti-IgE: reduces mast cell and basophil sensitivity — fewer exacerbations, reduced OCS dependence
- EXTRA trial: reduces asthma exacerbations by 25% in allergic asthma
- Delayed anaphylaxis: up to 24 hours post-injection — educate patient and prescribe epinephrine auto-injector
Safety Profile
Pregnancy insufficient-data
Lactation avoid
Renal Adjustment Not required
Hepatic Adjustment Not required
TDM Not required
Concordance Terms
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