Pediatric Sirolimus (Rapamycin®, Rapamune®) Uses and Side Effects

What Is Sirolimus?

Sirolimus medication is a new immunosuppressant drug originally approved for use in kidney transplant recipients. Ultimately, it will be used in all transplant patients. It is available as a 1mg/ml solution, in both multi-dose bottles and unit-dose pouches.

Sirolimus Uses

During transplant rejection, the transplanted organ stimulates lymphocytes in the body to multiply in response to certain molecules. Sirolimus inhibits the lymphocytes from multiplying in response to these molecules.

This action is different from those of other immunosuppressants like cyclosporine and tacrolimus. Instead of slowing down the lymphocytes, those immunosuppressants work on the molecules themselves. Because of this difference, sirolimus can be combined with other immunosuppressants. The interaction of sirolimus and these other immunosuppressants can have a combined effect that is even more beneficial than taking them individually.

You might hear your child’s transplant doctor refer to this effect as “synergistic”.

Sirolimus Dosage

Sirolimus dosage is available as a solution in a concentration of one mg/ml, either in multi-dose amber glass bottles or as liquid-filled, unit dose pouches.

How to Properly Take Sirolimus

Sirolimus medication should be mixed with two ounces of either orange juice or water and shaken vigorously just prior to administration. To ensure that the entire drug dose is taken, refill the cup used with four more ounces of either orange juice or water and have your child drink that as well.

The dose should be taken four hours after either cyclosporine or tacrolimus doses. Sirolimus must be stored in the refrigerator.

While your child is on this medication and for 24 hours afterwards, he or she should drink extra fluids and empty your bladder regularly. This helps the kidneys remove the drug from his or her body, and avoids some of the side effects.

Sirolimus Dosage

Initial studies indicate that sirolimus should be administered with full-doses of cyclosporine and prednisone. It is presently being studied with tacrolimus at Children’s Hospital of Pittsburgh of UPMC to determine appropriate combined doses.

Missed Doses

If your child misses a dose, inform your doctor or clinical coordinator. Do not double the dose to catch up. For best results, your child must take each dose of medication as scheduled and directed.

Sirolimus Side Effects

Common adverse side effects of sirolimus include:

  • High triglyceride and cholesterol levels
  • Decreased platelet and white blood cell counts (these usually go back to normal after discontinuation of the drug)
  • Anemia
  • High blood pressure
  • Elevated liver enzymes
  • Diarrhea
  • Pneumonia
  • Risk of viral infection.

If any of these side effects continues or becomes bothersome, inform your child’s doctor.

Sirolimus Drug Interactions

There are some medications that can interact with sirolimus and change its effectiveness. Tell your doctor or pharmacist about any prescription or over-the-counter medication your child is taking, so you can be warned of interactions and prevent them.

Precautions for Children

When any immunosuppressive drug is used, and especially when immunosuppressive agents are combined, there is the risk of infection and the possible development of PTLD, a lymphocyte disorder that may lead to cancer. Increased serum triglyceride and cholesterol levels should be monitored and may require treatment.

Although sirolimus is not believed to be dangerous to the kidneys, kidney function should be monitored when it is used with other immunosuppressants like cyclosporine.

Sirolimus Availability

Not all pharmacies stock sirolimus. Call your pharmacist at least five days before you need to fill a sirolimus prescription to make sure the medication will be available. CellCept may be available as an alternative.

Learn more about other Liver Transplant Drugs.

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