Sirolimus Immunosuppressant: Uses, Side Effects, & Interactions

Sirolimus (brand name: Rapamune) is an immunosuppressant medication that belongs to a group of drugs called mammalian target of rapamycin (mTOR) inhibitors. Please continue reading to find out what conditions sirolimus is used to treat and its side effects, interactions, and risks.

What is sirolimus used to treat?

Sirolimus is used to prevent organ rejection in kidney transplant patients in adults and children 13 years and older. Sirolimus is used along with other medications, such as cyclosporine and corticosteroids, after a kidney transplant to prevent organ rejection. Sirolimus inhibits the activity of the immune system and prevents it from rejecting the transplanted organ.

Sirolimus is also used to treat a condition called lymphangioleiomyomatosis (LAM), in which abnormal growths develop in the blood vessels, lymphatic vessels, and alveoli (air sacs) of the lungs.

Sirolimus is sometimes used to treat severe psoriasis, an autoimmune skin condition.

How to take sirolimus?

Sirolimus comes in the form of tablets or liquid solution to take by mouth, usually once a day. You can take this medicine either with or without food, but you need to be consistent in taking it the same way every time to help the sirolimus blood levels be more stable.

Read the prescription label carefully and take sirolimus exactly as directed. Do not change the dose, dosage frequency, or treatment duration without talking to the prescribing physician.

Swallow the sirolimus tablets whole. Do not cut, crush, or chew them. Talk to your doctor if you have swallowing problems. You can be prescribed sirolimus oral solution instead of oral tablets.

For sirolimus oral solution:

For the most accurate administration of this medication, you should use the oral dose syringe to withdraw the prescribed amount of sirolimus oral solution from the bottle, then empty the content of the syringe into a glass or plastic container with at least 2 ounces (60 mL) of water or orange juice.

The oral solution should be mixed with at least 60 mL (1/4 cup or 2 ounces) of water or orange juice, as mentioned. Do not mix sirolimus oral solution with other types of liquids or other juices, such as apple juice or grapefruit juice. Stir the mixture well and drink it immediately.

Make sure you refill the cup in which you put the sirolimus oral solution with an additional 4 ounces (120 mL or 1/2 cup) of water or orange juice and drink it to ensure you get the full dose of medicine.

You can carry sirolimus in a capped syringe for up to 24 hours at temperature. Once the oral solution is diluted, the mixture must be drunk immediately. Sirolimus solution can become hazy after refrigeration. This does not mean the medicine is spoiled or unsafe. Keep it at room temperature and shake the bottle until the haze clears.

Keep all your medical and lab appointments while you are on sirolimus. Your doctor may want to adjust your dose. Do not stop taking sirolimus without your doctor’s approval, even if you feel well and are symptom-free. Discontinuation could lead to organ rejection.

What are the side effects of sirolimus?

Common adverse effects of sirolimus include stomach pain, nausea, diarrhea, constipation, headache, and joint pain. Other common side effects that have been reported are low platelet counts, urinary tract infections, fever, and high blood sugar. Tell your doctor if these side effects are severe or do not go away after a few days once your body has gotten used to the medicine.

Less commonly, sirolimus can cause more serious side effects. Seek emergency medical care if you develop:

Unusual bleeding or bruising
Swelling of the hands, feet, and other body tissues, including the sac surrounding your heart causing trouble breathing.
Poor wound healing
Signs of infection such as painful urination, cold or flu symptoms, fever, and chills
Signs of anemia (low red blood cells) such as usual cold extremities, paleness, extreme fatigue, shortness of breath or lightheadedness.

In case of an overdose of sirolimus, seek immediate medical attention. Call 911 if someone has stopped breathing, had a seizure, is unresponsive, or has trouble breathing.

What are sirolimus drug interactions?

Interactions between sirolimus and your other medicines can cause serious side effects or make one or both medications ineffective. Potential drug interactions with sirolimus are described below:

These medications can lead to serious drug interactions with sirolimus and their extreme caution should be exercised:

Cyclosporine, tacrolimus
Tuberculosis medications: rifabutin (Mycobutin), rifampin;
Antimicrobials agents: clarithromycin (Biaxin), erythromycin (E.E.S., Erythrocin, E-Mycin), itraconazole (Sporanox), ketoconazole (Nizoral), and voriconazole (Vfend);

Caution should be exercised with the following medications. Your doctor may adjust the dosage to compensate for these drug interactions:

Medications that can cause an increase in sirolimus blood levels: bromocriptine (Cycloset, Parlodel), cimetidine (Tagamet), clotrimazole (Lotrimin), danazol (Danocrine), letermovir, fluconazole (Diflucan), diltiazem (Dilacor, Cardizem, Tiazac), nicardipine (Cardene), verapamil (Isoptin, Calan, Verelan, Covera), cannabidiol (CBD), HIV and hepatitis C treatment such as ritonavir (Norvir), indinavir (Crixivan), boceprevir, telaprevir;
Medications that can decrease sirolimus blood levels: Anti-seizure medications such as phenobarbital (Luminal), phenytoin (Dilantin), and carbamazepine (Tegretol), rifapentine, and herbal products such as St. John’s Wort
On the other hand, when being given together, sirolimus can increase the blood levels of verapamil

What precautions should I take while on sirolimus?

Allergic reactions

Before starting sirolimus, tell your doctor if you have ever had an allergic reaction to sirolimus, other immunosuppressant drugs, or any other medications.

Medications

Give your doctor and pharmacist a complete list of your medications, including prescription drugs, over-the-counter medications, dietary supplements, and herbal products.

Medical conditions

Tell your doctor if you have liver disease or high cholesterol.

Missed dose

If you miss a dose of sirolimus, take it as soon as you remember. However, if it is almost time for the next dose, skip the missed dose and go back to your regular dosing schedule. Do not take extra medicine or a double dose to make up for a missed dose.

Food and drinks

Avoid drinking grapefruit while on sirolimus.

Dose timing

If you are taking the soft gelatin capsules of a medication called cyclosporine (Neoral), take them at least 4 hours before your sirolimus dose.

Vaccinations

You should not receive a “live” vaccine while on sirolimus. Sirolimus can cause the vaccine to be less effective. You should check with your healthcare provider first before getting any vaccine.

Procedures

Tell all your healthcare providers you are on sirolimus, including before medical and dental procedures.

Pregnancy and lactation

Before starting sirolimus, tell your doctor if you are pregnant or breastfeeding. Call your doctor without delay if you become pregnant while on sirolimus. You will need to be on an effective birth control method before starting treatment with this medicine, while you are on it, and for 12 weeks after stopping sirolimus.

What are sirolimus warnings and risks?

Sirolimus is an immunosuppressant medication that suppresses the body’s immune system. It can, therefore, increase your risk of infection and cancer, especially lymphoma (a type of blood cancer) and skin cancer.

Sirolimus is prescribed to kidney transplant patients. The safety and efficacy of this medication have not been established in patients who have received liver transplantation or lung transplantation.

Wear protective clothing and sunblock with at least SPF30 to lower your risk of skin cancer. Call your doctor immediately if you develop signs and symptoms of active infections, such as fever, chills, sore throat, frequent urination, pain with urination, mouth sores, skin changes, night sweats, swollen glands, and weight loss while on sirolimus.

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