RHO(D) IMMUNE GLOBULIN

Rh_o(D) IMMUNE GLOBULIN
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RhoGAM, Rhophylac, WinRho SDF
Rh_o(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.

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

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