What is efalizumab, and how does it work (mechanism of action)?
Efalizumab is a synthetic (man-made) antibody that is used for the treatment of psoriasis.Psoriasis is a disease of the skin in which the cells of the skin reproduce more rapidly than normal. This increased reproduction is thought to be stimulated by activation of the immune system, in particular, the lymphocytes. In order for lymphocytes to become activated, they must adhere (attach) to other cells through receptors on their surface. Efalizumab blocks one of these receptors (called leukocyte function antigen-1 or LFA-1) on the lymphocyte. By blocking adhesion, efalizumab prevents the activation of lymphocytes that is responsible for psoriasis.
What are the side effects of efalizumab?
Reactions to the first dose of efalizumab include headache, fever, nausea, and vomiting and are dose-level related, that is, the higher the dose the more likely are reactions. With the currently recommended first dose (0.7 mg/kg), one in three patients will have a reaction.
Efalizumab suppresses the immune system and there have been reports of infections including serious infections and infections that worsen despite treatment with antibiotics. It also is possible that this immune-suppressing effect may increase the risk for tumors. Low platelet counts may occur increasing the risk of bleeding. An immune-mediated anemia due to the destruction of red blood cells also has been reported.
Efalizumab increases the risk for progressive multifocal leukoencephalopathy (PML), a rare, serious, progressive disease of the nervous system caused by a virus. PML usually occurs in people with severely weakened immune systems resulting in an irreversible decline in function of the nervous system and death. There is no known effective treatment for PML. Patients receiving efalizumab therapy should be monitored for symptoms that suggest PML. If PML is suspected, efalizumab should be discontinued.
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- What is efalizumab, and how does it work (mechanism of action)?
- What brand names are available for efalizumab?
- Do I need a prescription for efalizumab?
- What are the side effects of efalizumab?
- What is the dosage for efalizumab?
- Which drugs or supplements interact with efalizumab?
- Is efalizumab safe to take if I'm pregnant or breastfeeding?
- What else should I know about efalizumab?
What is the dosage for efalizumab?
Efalizumab is given as weekly subcutaneous (beneath the skin) injections. The first dose is 0.7 mg per kilogram of body weight (1 kilogram equals 2.2 pounds). Thereafter, each weekly dose is 1 mg per kilogram (up to a maximum single dose of 200 mg).
Efalizumab should be administered using the disposable syringe and needles provided in the kit. The cap on the pre-filled syringe containing sterile water should be removed. Thereafter, the needle is attached to the syringe. Remove the plastic cap protecting the rubber stopper of the efalizumab vial and wipe the top of the rubber stopper with one of the provided alcohol swabs. After cleaning with the alcohol swab, do not touch the top of the vial. To prepare the efalizumab solution, slowly inject the 1.3 mL of sterile water in the provided pre-filled syringe into the efalizumab vial. Swirl the vial with a gentle circular motion to dissolve the product. Do not shake. This procedure should be done immediately before each use, and the solution that is made should be used only once. If it is not used immediately after it is made, store at room temperature and use within 8 hours. Following administration, discard any unused reconstituted efalizumab solution. Potential sites for injection include the thigh, abdomen, buttocks, or upper arm. Injection sites should be rotated.
Which drugs or supplements interact with efalizumab?
The safety and efficacy of efalizumab in combination with other immune-suppressing medicines have not been evaluated. It is recommended that patients receiving other immune-suppressing medicines should not receive efalizumab because of the possibility of increasing the risks of infections and tumors. The safety and efficacy of vaccines administered to patients being treated with efalizumab also have not been studied. Some vaccines consisting of live viruses which have been rendered inactive (attenuated) should not be used in patients taking efalizumab
Is efalizumab safe to take if I'm pregnant or breastfeeding?
Reproduction studies in animals have not been conducted with efalizumab. It also is not known whether efalizumab can cause harm to the fetus in humans. Therefore, efalizumab should be given to a pregnant woman only if the physician feels that its benefits clearly warrant the theoretical risks and with the patient's consent. Female patients also should notify their physicians if they become pregnant while taking efalizumab (or within 6 weeks of discontinuing efalizumab) and be encouraged to enroll in the RAPTIVA Pregnancy Registry.
It is not known whether efalizumab passes into breast milk. Since animal data suggest a potential for side effects in nursing infants from similar (but not commercially available) drugs, a decision must be carefully made whether to discontinue nursing while taking efalizumab or to discontinue efalizumab, taking into account the importance of the drug to the mother.
What else should I know about efalizumab?
What preparations of efalizumab are available?
Vial of 125 mg lyophilized (freeze-dried) powder, prefilled syringe containing sterile water for reconstitution, and syringes and needles for injection.
How should I keep efalizumab stored?
Efalizumab must be stored at refrigerated temperature, between 2 and 8°C (36-46°F). Reconstituted efalizumab must be used within eight hours. Keep this medicine - as well as all others - away from the reach of children.
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Reference: FDA Prescribing Information