Health Information and Tools >  Organ Transplants: Anti-Rejection Medicines
Facebook Tweet Share

Main Content

Organ Transplants: Anti-Rejection Medicines


People who've had an organ transplant need anti-rejection medicines. That's because the immune system will try to destroy the new organ. These medicines weaken your immune system and make it harder for your body to destroy your new organ. But they also make it harder for your body to fight infections, cancer, and other diseases.

Types of anti-rejection medicine you may need to take include:

  • Corticosteroids.
  • Calcineurin inhibitors.
  • Antiproliferative agents.
  • Monoclonal antibodies.
  • Polyclonal antibodies.

These medicines are also called immunosuppressants.


You get a dose of a steroid medicine before your transplant. These medicines include prednisone and methylprednisolone. They make your immune system less active. They also reduce inflammation and prevent rejection of the organ. A high does is usually continued after your surgery. Then the dosage is slowly reduced to the lowest dose that helps prevent rejection.

Taking steroid medicine for just a few days may cause short-term side effects. These include stomach upset, facial swelling, fluid retention, high blood sugars, acne, thinning of skin, high blood pressure, weight gain, sleep problems, and anxiety. High doses can sometimes cause more severe side effects, such as extreme agitation, paranoia, psychosis, and hallucinations.

Calcineurin inhibitors block the message that causes rejection. Examples include tacrolimus and cyclosporine. You probably will always need to take these medicines. Side effects include high blood pressure, too much potassium in the blood, diabetes, and kidney problems. These medicines can also cause nausea, vomiting, diarrhea, high cholesterol, swelling of gums, increased hair growth, tremors, and seizures.

Antiproliferative agents

Antiproliferative agents prevent the immune cells from multiplying. These medicines include mycophenolate and azathioprine. They prevent your immune system from attacking and destroying the donor organ. Common side effects can include nausea, anemia, high triglycerides, and intestinal upset.

Monoclonal antibodies

Monoclonal antibodies block the growth of immune cells that are responsible for rejection. These medicines include basiliximab, and rituximab. They are given through an intravenous (IV) and are used early after transplantation along with calcineurin inhibitors and antiproliferative agents.

Polyclonal antibodies

Polyclonal antibodies deplete the body's immune cells for a short time. These medicines include anti-thymocyte globulin-equine and anti-thymocyte globulin-rabbit. They are given through an intravenous (IV) and are used in the hours and days right after your organ transplant. They prevent your body from rejecting the donor organ. They may also be used again if your body starts to reject the donor organ.

They are often used to reduce early use of calcineurin inhibitors, which can have serious side effects. Side effects of polyclonal antibodies include fever, chills, leukopenia, itching, and joint pain.

Related Information


Adaptation Date: 4/5/2023

Adapted By: Alberta Health Services

Adaptation Reviewed By: Alberta Health Services

Adapted with permission from copyrighted materials from Healthwise, Incorporated (Healthwise). This information does not replace the advice of a doctor. Healthwise disclaims any warranty and is not responsible or liable for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.