RHO(D) IMMUNE GLOBULIN

Rho(D) IMMUNE GLOBULIN (row) RhoGAM, Rhophylac, WinRho SDF Rho(D) IMMUNE GLOBULIN MICRO-DOSE BayRho-D Mini Dose, MICRhoGAM Classifications: biologic response modifier; immunoglobulin; Therapeutic: immunoglobulin Prototype: Immune globulin Pregnancy Category: C

Availability

RhoGAM, MICRhoGAM: 5% solution in prefilled syringes;

Rhophylac: 300 mcg prefilled syringe;

WinRho SDF: 120 mcg, 300 mcg, 1000 mcg vials

Action

Sterile nonpyrogenic gamma globulin solution containing immunoglobulins (IgG) of at least 90% IgG, which provides passive immunity by suppressing active antibody response and formation of anti-Rh_o(D) in Rh-negative [Rh_o(D)-negative] individuals previously exposed to Rh-positive [Rh_o(D)-positive, D^u-positive] blood.

Therapeutic Effect

Effective for exposure in Rh-negative women when Rh-positive fetal RBCs enter maternal circulation during third stage of labor, fetal-maternal hemorrhage (as early as second trimester), amniocentesis, or other trauma during pregnancy, termination of pregnancy, and following transfusion with Rh-positive RBC, whole blood, or components (platelets, WBC) prepared from Rh-positive blood.

Uses

To prevent isoimmunization in Rh-negative individuals exposed to Rh-positive RBC (see above). Rh_o(D) immune globulin micro-dose is for use only after spontaneous or induced abortion or termination of ectopic pregnancy up to and including 12 wk of gestation. Treatment of idiopathic thrombocytopenia purpura.

Contraindications

Rh_o(D)-positive patient; person previously immunized against Rh_o(D) factor, hypersensitivity for thimerosal, severe immune globulin hypersensitivity, bleeding disorders; pregnancy (category C), neonates.

Cautious Use

IgA deficiency.

Route & Dosage

Note: Only WinRho SDF can be given IV. BayRho-D and RhoGAM are available in regular and mini-dose vials. Antepartum Prophylaxis Adult: IM/IV 300 mcg at approximately 28-wk gestation; followed by 1 vial of mini-dose or 120 mcg within 72 h of delivery if infant is Rh-positive Postpartum Prophylaxis Adult: IM/IV 300 mcg preferably within 72 h of delivery if infant is Rh-positive Following Amniocentesis, Miscarriage, Abortion, Ectopic Pregnancy Adult: IM If over 13-wk gestation, 300 mcg, preferably within 3 h but at least within 72 h; if less than 13 wk, give 50 mcg Transfusion Accident Adult: IM/IV 300 mcg for each volume of RBCs infused divided by 15, given within at least 72 h of accident Child: IV Administer 600 mcg q8h until total dose given. Exposure to positive whole blood 9 mcg/mL, exposure to positive RBCs 18 mcg/mL. IM Administer 1200 mcg q12h until total dose given. Exposure to positive whole blood 12 mcg/mL, exposure to positive RBCs 24 mcg/mL. Idiopathic Thrombocytopenia Purpura Adult/Child: IV 50 mcg/kg, then 25–60 mcg/kg depending on response

Administration

Note: Each vial of Rh_o(D) immune globulin contains enough anti-Rh_o(D) to suppress the immunizing potential of 15 mL Rh-positive packed RBC. Each vial of micro-dose contains enough anti-Rh_o(D) to suppress the immune response to 2.5 mL of Rh-positive packed RBC.

Intramuscular

• Make sure that lot numbers of drug used for the cross-match and the drug to be administered are the same.
• Administer Rh_o(D) immune globulin via IM to the mother only; not to the infant.
• Use the deltoid muscle. Give in divided doses at different sites, all at once or at intervals, as long as the entire dose is given within 72 h after delivery or termination of pregnancy.
• Reconstitute with 1.25 mL of NS (using the same method to dissolve as for IV). Give immediately after reconstitution.
• Keep epinephrine immediately available; systemic allergic reactions sometimes occur.

Intravenous PREPARE: Direct: No dilution is required for products supplied in liquid form. • Reconstitute powder vials as follows: Add 2.5 mL diluent (provided by manufacturer) to each 600 or 1500 IU vial; add 8.5 mL diluent (provided by manufacturer) to each 5000 IU vial. • Direct stream of diluent to side of vial, swirl to dissolve, do not shake. Concentration of reconstituted vials: 600 IU yields 240 IU/mL, 1500 IU vial yields 600 IU/mL, and 5000 IU vial yields 588 IU/mL.  ADMINISTER: Direct: Give a single dose over 3–5 min.

• Refrigerate commercially prepared solutions, although it may remain stable up to 30 d at room temperature according to manufacturers. Discard solutions that have been frozen. Store powder at 2°–8° C (36°–46° F) unless otherwise directed; avoid freezing.

Adverse Effects (≥1%)

Body as a Whole: Injection site irritation, slight fever, myalgia, lethargy.

Interactions

Drug: May interfere with immune response to live virus vaccine; should delay use of live virus vaccines for 3 mo after administration of Rh_o(D) immune globulin.

Pharmacokinetics

Peak: 2 h IV, 5–10 d IM. Half-Life: 25 d.

Nursing Implications

Assessment & Drug Effects

• Obtain history of systemic allergic reactions to human immune globulin preparations prior to drug administration.
• Send sample of newborn's cord blood to laboratory for cross-match and typing immediately after delivery and before administration of Rh_o(D) immune globulin. Confirm that mother is Rh_o(D) and D^u-negative. Infant must be Rh-positive.

Patient & Family Education

• Be aware that administration of Rh_o(D) immune globulin (antibody) prevents hemolytic disease of the newborn in a subsequent pregnancy.

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Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug