Siltuximab

Siltuximab is a prescription medication used to treat a rare disease of lymph nodes and related tissues called multicentric Castleman's disease (MCD). While not officially a cancer, MCD acts similarly to Lymphoma, a cancer of the lymph nodes. MCD causes an abnormal overgrowth of immune cells in lymph nodes and related tissues in the body.

Siltuximab is an injection that works by blocking a protein that stimulates abnormal growth of immune cells. 

Common side effects include itchy skin (pruritis), weight gain, rash, increased levels of uric acid in the blood and upper respiratory tract infection.

Siltuximab is a prescription medication used to treat multicentric Castleman's disease (MCD). It is intended for patients with MCD who do not have HIV or human herpes virus 8 (HHV-8).

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

Siltuximab may be found in some form under the following brand names:

• Sylvant

Serious side effects have been reported with siltuximab. See the “Siltuximab Precautions” section.

Common side effects of siltuximab include the following:

• rash
• itchy skin (pruritis)
• upper respiratory tract infection
• weight gain
• increased blood level of uric acid

This is not a complete list of siltuximab side effects. Ask your doctor or pharmacist for more information.

Tell your doctor if you have any side effect that bothers you or that does not go away.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Tell your doctor about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you take:

• medications that use the enzyme CYP450 such as:

  • warfarin (Coumadin, Jantoven)
  • cyclosporine (Neoral, Sandimmune, Gengraf)
  • theophylline
  • lovastatin (Mevacor)
  • atorvastatin (Lipitor)
  • oral contraceptives

This is not a complete list of siltuximab drug interactions. Ask your doctor or pharmacist for more information.

Serious side effects have been reported with siltuximab including the following:

• Infections. Siltuximab may lower your ability to fight infections. Tell your healthcare provider right away if you have any signs or symptoms of an infection during treatment with siltuximab.
• Infusion and allergic reactions. If you have an infusion or allergic reaction while receiving siltuximab, your healthcare provider will stop your infusion and treat your reaction. If you have a severe infusion or allergic reaction, your healthcare provider may stop your treatment completely. Tell your healthcare provider or get medical help right away if you have any of these symptoms during or after your infusion of siltuximab:
  • trouble
  • breathing
  • chest
  • tightness
  • wheezing
  • dizziness
  • or light-headedness, swelling of the lips, or skin rash

Do not take siltuximab if you are allergic to siltuximab or to any of its ingredients.

Medications can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of siltuximab, there are no specific foods that you must exclude from your diet when receiving this medication.

Before taking siltuximab, tell your doctor about all of your medical conditions. Especially tell your doctor if you:

• are allergic to siltuximab or to any of its ingredients
• have an infection. You should not receive siltuximab if you have a severe infection.
• have had a recent vaccination or are scheduled to receive any vaccinations. You should not receive a live vaccine during your treatment with siltuximab.
• have or have had any stomach or bowel (intestine) problems, such as diverticulitis or ulcers. Tell your healthcare provider if you have pain in your stomach area.
• are pregnant or plan to become pregnant. It is not known if siltuximab will harm your unborn baby. You should not become pregnant while receiving treatment with siltuximab. Females who are able to become pregnant should use effective birth control during treatment with siltuximab and for 3 months after stopping treatment.
• are breastfeeding or plan to breastfeed. It is not known if siltuximab passes into your breast milk. You and your healthcare provider should decide if you will take siltuximab or breastfeed. You should not do both.

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements.

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

Siltuximab falls into category C. There are no well-controlled studies that have been done in pregnant women. Siltuximab should be used during pregnancy only if the possible benefit outweighs the possible risk to the unborn baby.

Tell your doctor if you are breastfeeding or plan to breastfeed.

It is not known if siltuximab crosses into human milk. Because many medications can cross into human milk and because of the possibility for serious adverse reactions in nursing infants with use of this medication, a choice should be made whether to stop nursing or stop the use of this medication. Your doctor and you will decide if the benefits outweigh the risk of using siltuximab.

Take siltuximab exactly as prescribed.

Siltuximab is available in an injectable form to be given directly into a vein (IV) by a healthcare professional and is given over 1 hour by intravenous infusion every 3 weeks.

If you miss a dose, be sure to make a follow up appointment.

Take this medication exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.

The dose your doctor recommends may be based your weight.

The recommended dose of siltuximab for the treatment of multicentric Castleman's disease (MCD) is 11 mg/kg dose given over 1 hour by intravenous infusion every 3 weeks.

If siltuximab is administered by a healthcare provider in a medical setting, it is unlikely that an overdose will occur. However, if overdose is suspected, seek emergency medical attention.

• Keep all appointments with your doctor.