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Rho(D) immune globulin (Gamulin Rh, HypRho-D MICRhoGAM, MiniGamulin Rh, Rhesonativ, RhoGAM, WinRho)

Indications: 1) prevent alloimmunization in Rh-negative women exposed to Rh+ blood a) during delevery of an Rh+ infant b) as a result of abortion c) following amniocentesis or abdominal trauma d) following a transfusion accident 2) Rh isoimmunization - to prevent hemolytic disease of the newborn if there is a subsequent pregnancy with an Rh+ fetus 3) treatment of refractory immune thrombocytopenic purpura (ITP) Contraindications: 1) Rho(D)-positive patient 2) hypersensitivity to immune globulins or thimerosal 3) transfusion of Rho(D)+ blood in previous 3 months 4) prior sensitization to Rho(D) Caution: 1) do not inject IV 2) do not administer to neonates pregnancy-category C safety in lactation ? Dosage: Obstetrical: 1) 1 vial (300 ug) IM prevents maternal sensitization of fetal RBC volume that has entered maternal circulation is < 15 mL 2) if more, give additional vials 3) number of vials = RBC volume (mL) of fetomaternal hemorrhage divided by 15 Postpartum prophylaxis: - 1 vial (300 ug) IM within 72 hours of delivery Antepartum prophylaxis: 1) 1 vial (300 ug) IM at 26-28 weeks of gestation 2) followed by another vial (300 ug) IM within 72 hours of delivery if fetus is Rh+ Following miscarriage, abortion, or termination of ectopic pregnancy: 1) up to 13 weeks of gestation: - 50 ug IM within 3 hours, but may be given up to 72 hours later 2) after 13 week of gestation: 300 ug IM Injection: 1) (RhoGAM, HypRho-D) each vial contains 300 ug 2) MICRhoGAM each vial contains 50 ug Benefit/risk: - Rhogam at 28 & 24 weeks of gestation in at risk women - unclear benefit [3] - Rhogam postpartum in at risk women - number needed to treat = 8 to prevent alloimmunization in a future pregnancy [3] Pharmacokinetics: elimination: liver Adverse effects: 1) most common (1-10%) - headache, fever, chills, hemolysis (Hgb drop of > 2 g/dL in 5-10% of patients with ITP), slight swelling at site of injection 2) rare [2] a) severe & sometimes fatal, intravascular hemolysis b) disseminated intravascular coagulation in patients with ITP Notes: - Acetaminophen may ease minor discomfort after vaccination.

Related

Rhesus blood group cluster

General

immune globulin (Gamastan, Gamimune N, Gammagard, Gammar, Sandoglobulin, Venoglobulin-I, Venoglobulin-S, ISG, Vivaglobulin, Gamunex, Privigen, Gammaplex, Flebogamma, Gammaked, Bivigam, Carimune, Hizentra)

References

  1. Kaiser Permanente Northern California Regional Drug Formulary, 1998
  2. FDA Medwatch http://www.fda.gov/medwatch/safety/2006/safety06.htm#WinRho
  3. The NNT: Anti-D (Rh Factor) Administration During Late Pregnancy for the Prevention of Alloimmunization in At-Risk Women. http://www.thennt.com/nnt/rhogam-in-late-pregnancy-for-prevention-of-sensitization-in-at-risk-women/ - The NNT: Anti-D (Rh Factor) Immunoglobulin Administration Postpartum for the Prevention of Alloimmunization in At-Risk Women. http://www.thennt.com/nnt/rhogam-postpartum-for-prevention-of-sensitization-in-at-risk-women/ - Crowther C, Middleton P. Anti-D administration after childbirth for preventing Rhesus alloimmunisation. Cochrane Database Syst Rev. 2000;(2):CD000021. PMID: 10796089