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Rhophylac Dosage

Medically reviewed by Drugs.com. Last updated on Feb 5, 2021.

Generic name: HUMAN RHO(D) IMMUNE GLOBULIN 1500[iU] in 2mL
Dosage form: injection

Observe patients for at least 20 minutes following administration of RHOPHYLAC.

Preparation and Handling

  • RHOPHYLAC is a clear or slightly opalescent, colorless to pale yellow solution. Inspect RHOPHYLAC visually for particulate matter and discoloration prior to administration. Do not use if the solution is cloudy or contains particulates.
  • Prior to intravenous use, ensure that the needle-free intravenous administration system is compatible with the tip of the RHOPHYLAC glass syringe.
  • Do not freeze.
  • Bring RHOPHYLAC to room temperature before use.
  • RHOPHYLAC is for single dose only. Dispose of any unused product or waste material in accordance with local requirements.

Administration

DO NOT confuse micrograms (mcg) with International Units (IU) when calculating the dose of RHOPHYLAC. Miscalculations could result in a significant overdose or underdose of the product. Note that 1 mcg = 5 IU of RHOPHYLAC.

Suppression of Rh Isoimmunization

RHOPHYLAC should be administered by intravenous or intramuscular injection. If large doses (greater than 5 mL) are required and intramuscular injection is chosen, it is advisable to administer RHOPHYLAC in divided doses at different sites.

Ensure the site of administration will allow the injection to reach the muscle if RHOPHYLAC is administered intramuscularly. Consider intravenous administration if reaching the muscle is of concern [see Adverse Reactions (6.2)]. Do not administer RHOPHYLAC subcutaneously into the fatty tissue.

Refer to Table 1 (for dosing instructions in micrograms) and Table 2 (for dosing instructions in International Units) by indication.

Table 1. Dosing Guidelines based on Micrograms (mcg) for Suppression of Rh Isoimmunization
MICROGRAMS (mcg)
Indication Timing of Administration Dose*
(Administer by intravenous (IV) or intramuscular (IM) injection)
*
A 300 mcg dose of RHOPHYLAC will suppress the immunizing potential of ≤15 mL of fetal Rh(D)-positive RBCs.1
The dose of RHOPHYLAC must be increased if the patient is exposed to >15 mL of fetal Rh(D)-positive RBCs; in this case, follow the dosing guidelines for excessive fetomaternal hemorrhage.
Rh-incompatible pregnancy
Routine antepartum prophylaxis Week 28-30 of pregnancy 300 mcg
Postpartum prophylaxis (required only if the newborn is Rh(D)-positive, or of unknown status) Within 72 hours of birth 300 mcg
Obstetric complications (e.g., miscarriage, abortion, threatened abortion, ectopic pregnancy or hydatidiform mole, transplacental hemorrhage resulting from antepartum hemorrhage) Within 72 hours of complication 300 mcg
Invasive procedures during pregnancy (e.g., amniocentesis, chorionic biopsy) or obstetric manipulative procedures (e.g., external version, abdominal trauma) Within 72 hours of procedure 300 mcg
Excessive fetomaternal hemorrhage (>15 mL fetal RBCs) Within 72 hours of complication 300 mcg plus:
  • 20 mcg per mL Rh(D)-positive fetal RBCs in excess of 15 mL if excess transplacental bleeding is quantified
    or
  • An additional 300 mcg dose if excess transplacental bleeding cannot be quantified
Incompatible transfusions Within 72 hours of exposure 20 mcg per 2 mL transfused Rh(D)-positive whole blood or per 1 mL Rh(D)-positive RBCs
Table 2. Dosing Guidelines based on International Units (IU) for Suppression of Rh Isoimmunization
INTERNATIONAL UNITS (IU)
Indication Timing of Administration Dose*
(Administer by intravenous (IV) or intramuscular (IM) injection)
*
A 1500 IU dose of RHOPHYLAC will suppress the immunizing potential of ≤15 mL of fetal Rh(D)-positive RBCs.1
The dose of RHOPHYLAC must be increased if the patient is exposed to >15 mL of fetal Rh(D)-positive RBCs; in this case, follow the dosing guidelines for excessive fetomaternal hemorrhage.
Rh-incompatible pregnancy
Routine antepartum prophylaxis Week 28-30 of pregnancy 1500 IU
Postpartum prophylaxis (required only if the newborn is Rh(D)-positive, or of unknown status) Within 72 hours of birth 1500 IU
Obstetric complications (e.g., miscarriage, abortion, threatened abortion, ectopic pregnancy or hydatidiform mole, transplacental hemorrhage resulting from antepartum hemorrhage) Within 72 hours of complication 1500 IU
Invasive procedures during pregnancy (e.g., amniocentesis, chorionic biopsy) or obstetric manipulative procedures (e.g., external version, abdominal trauma) Within 72 hours of procedure 1500 IU
Excessive fetomaternal hemorrhage (>15 mL fetal RBCs) Within 72 hours of complication 1500 IU plus:
  • 100 IU per mL fetal RBCs in excess of 15 mL if excess transplacental bleeding is quantified
    or
  • An additional 1500 IU dose if excess transplacental bleeding cannot be quantified
Incompatible transfusions Within 72 hours of exposure 100 IU per 2 mL transfused Rh(D)- positive whole blood or per 1 mL RBCs

Treatment of ITP

For treatment of ITP, ADMINISTER RHOPHYLAC BY THE INTRAVENOUS ROUTE ONLY [see Dosage and Administration (2.1)]. Do not administer intramuscularly.

Calculate the dose of RHOPHYLAC for ITP on the basis of the patient's weight in kilograms (kg). Inappropriate use of pounds (lbs) will result in an overdose.

Table 3. Dosing Guidelines for ITP
Dose (mcg) Rate of administration
mcg = microgram
50 mcg per kg body weight 2 mL per 15 to 60 seconds

The following formula can be used to calculate the number of syringes of RHOPHYLAC to administer:

Dose (50 mcg) x body weight (kg) = Total mcg / 300 mcg per syringe = Number of syringes

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.