Siltuximab (Intravenous)

Siltuximab is a drug only available upon prescription, which is injected into patients suffering from Multicentric Castleman's Disease (MCD).


Siltuximab is a prescription-only drug that is given via intravenous form to those suffering from Multicentric Castleman's Disease (MCD). MCD is a rare blood disorder that affects the lymph nodes, as well as related tissues. Siltuximab is not a drug that you take yourself at home, but is instead injected during regular appointments by a trained nurse or doctor.

Siltuximab is not to be used in patients who have HIV and HHV-8 (human herpes virus-8).

Conditions treated

  • Multicentric Castleman's Disease

Type of Medicine

  • Powder for an injectable solution.

Side Effects

There are a number of side effects that can occur whilst taking Siltuximab.

If you experience any of the following side effects, then contact your doctor or nurse immediately:

  • Cough
  • Decreased amount or frequency of urine
  • Black, tarry stools
  • Blurred vision
  • Vomiting
  • Loss of appetite
  • Loss of voice
  • Side or lower back pain
  • Body aches or pain
  • Chills
  • Confusion
  • Bloating or swelling of the feets, face, hands, lower legs, or arms
  • Increased thirst
  • Troubled breathing
  • Unusual bruising or bleeding
  • Bloody urine
  • Difficulty with breathing
  • Lightheadedness, dizziness or faintness when getting up suddenly from a sitting or lying position
  • Ear congestion
  • Fever
  • Full or bloated feeling
  • Pressure in the stomach
  • Rapid weight gain
  • Headache
  • Unusual weakness or tiredness
  • Unusual weight loss or gain
  • Nasal congestion
  • Sore throat
  • Sweating
  • Nausea
  • Sneezing
  • Bleeding gums
  • Stomach or abdominal pain
  • Swelling of stomach or abdominal area
  • Tingling of the hands or feet
  • Pinpoint red spots on the skin
  • Runny nose

Less common:

  • Back pain
  • Fainting
  • Fast, irregular, pounding, or racing pulse or heartbeat
  • Sunken eyes
  • Unusually warm skin
  • Wrinkled skin
  • Dizziness
  • Lightheadedness
  • Dry mouth
  • Feeling of warmth
  • Chest pain or discomfort
  • Rapid breathing
  • Redness of the arms, face, neck and occasionally, upper chest
  • Flushing or redness of the skin


  • Difficulty with swallowing
  • Swelling or puffing of the eyelids or around the tongue, lips, eyes or face
  • Tightness in the chest
  • Skin rash, itching or hives

There are also the following side effects which, though uncomfortable, do not necessarily require you to seek medical assistance:

  • Difficulty with bowel movements
  • Rash with small raised lesions or flat lesions on the skin
  • Darkening of the skin
  • Difficulty moving
  • Muscle stiffness or pain
  • Joint pain, swelling, or stiffness
  • Dry skin
  • Skin rash, scaly, oozing and crusted
  • Decreased appetite

If you experience any of the above and they are worrying you then you can still contact your doctor. They may have a way to reduce the effects slightly or make them more bearable.

If you experience any other side effects and think they may be related to Siltuximab, then you can still contact your doctor.


The usual dosage for treating CMD is having one injection every 3 weeks with the dosage calculated at 11 mg per kg of body weight. Under no circumstances is Siltuximab to be administered at home, instead, it should be given by a trained healthcare professional in a medical environment. Siltuximab is administered intravenously, and patients are required to remain for one hour with the needle in whilst the drug is infused.

Your doctor will advise you on how long you must undergo treatment, though it may typically continue until the drug shows signs of no ongoing benefits or difference being made to your condition. During the course of your treatment, you will undergo regular visits to your doctor who can measure the effects it is having and whether or not it is suitable for you to continue.


As with any drugs you are prescribed or are taking, there is the chance that Siltuximab will react with other medication. In some circumstances, you may then be advised not to take Siltuximab, or you may be advised to stop taking the alternate medication.

Below you can find a list of medications that Siltuximab is known to react to in some form or another:

  • Alfentanil
  • Aminophylline
  • Artemether
  • Astemizole
  • Carbamazepine
  • Cisapride
  • Cyclosporine
  • Dihydroergotamine
  • Ergotamine
  • Fentanyl
  • Iloperidone
  • Lumefantrine
  • Paclitaxel
  • Phenytoin
  • Pimozide
  • Quinidine
  • Sirolimus
  • Tacrolimus
  • Terfenadine
  • Theophylline
  • Warfarin

You should make it perfectly clear to your doctor which forms of medication you are currently on, especially with regards to any of those listed. Together, you and your doctor can come to an informed decision as to whether Siltuximab is the right course of treatment for you, or if some sort of reduced dosage combination would be recommended. Please be aware that this list is not all-inclusive, and instead, your doctor is best informed to prescribe you Siltuximab. When notifying your doctor, also discuss any herbal or vitamin supplements you take.

Beyond drugs, Siltuximab has the capabilities of interacting with a variety of foods and drink and well as tobacco. So, whilst you are consulting over your condition with the doctor, give an accurate and in-depth account of your dietary intake. You may well need to restrict or remove certain elements from your daily diets, such as no tobacco or alcohol. Alternatively, they may be able to advise a different solution or ways in which you could alter your dosages.

Finally, make your doctor totally aware of any medical conditions you currently have. Siltuximab may interact with certain medical conditions which could lead to uncomfortable or damaging outcomes. Again, the list of possible medical interactions is wide-ranging and they can best advise you. It may be the case you can expect some minor discomfort, but that taking Siltuximab is still the best route to improve your MCD.

Do point out any knowledge of yourself suffering from:

  • A severe infection

Having a severe infection greatly reduces your immune system's ability to fight off other illnesses. You should first treat the existing infection before starting on Siltuximab.

  • Bowel or stomach problems

This includes problems such as stomach ulcers or diverticulitis. Taking Siltuximab with this may increase the chance of gastrointestinal perforation.


Make your doctor aware of any allergies you have, including those to plants, foods, animals, dyes or preservatives. Such allergies may cause severe aggravation alongside Siltuximab. Similarly, make them aware of any allergies you have to other drugs, or if you begin to experience any sort of reactions or unwelcome side effects one you start taking Siltuximab.

As of the time of writing, there has not been any safety or efficacy standards put in place regarding the relationship between Siltuximab and pediatric patients. There have not been the appropriate studies to determine whether or not it poses any sort of direct threat to younger patients suffering from MCD. Your doctor is best disposed to ascertain whether or not it is best for your child to start using Siltuximab.

The appropriate studies carried out so far on older patients have not determined any sort of geriatric-specific problems of taking Siltuximab. It would appear that it is still a useful drug to take in helping older patients. Though, being elderly may cause you to have a certain weakness to other ailments which could, in turn, make it less advisable to take Siltuximab. Your doctor is best-suited to make that decision.

There is a lack of any suitable studies to demonstrate whether Siltuximab poses any increased threat to a pregnant woman. It may also be the case that some animal studies carried out have shown some sort of adverse effect, though this is unclear. Your doctor will be aware of latest research and studies in deciding whether you are safe to take this drug whilst pregnant. Either way, if you become pregnant whilst undergoing a course of Siltuximab, make your doctor aware as they may need to review your situation.

With regards to breastfeeding women, there have not, as of writing, been suitable studies which would demonstrate any sort of risk of taking Siltuximab. Instead, the benefits of taking the drug need to be carefully weighed against any potential risks that could occur.

It is crucial that you do not miss any appointments with your doctor whilst you are receiving treatment of Siltuximab. Failure to take your dosage every three weeks will greatly impact upon the benefits you will receive and the overall effectiveness of the treatment. Those appointments are also crucial to the doctor being able to monitor your general health to see any unwanted side effects that may be occurring. Under such circumstances, blood tests may be needed to ascertain your physical well being.

It is highly recommended that you use suitable birth control during the time that you are receiving Siltuximab. You should also continue to use birth control for three months following your final injection of Siltuximab. This ensures the highest level of safety both to you and any child that may be conceived.

When taking Siltuximab, your immune system will naturally be very weakened and you will be more susceptible to getting some form of infection. Your body is far less able to fight back against infections, so you must monitor your condition closely.

If you experience any of the following symptoms at any time, then contact your doctor immediately:

  • Flu-like symptoms
  • Cough
  • Fever
  • Unusual weakness or tiredness
  • Chills

This also means you shouldn't receive any sorts of vaccinations whilst taking Siltuximab. Live virus vaccines work by exposing your immune system to a small amount of the intended virus, but with your systems weakened you are not properly equipped to tackle the vaccine.

One severe allergic reaction which can occur is called anaphylaxis. It can be extremely severe and requires immediate medical attention as it is life-threatening.

If you show any of the following symptoms whilst taking Siltuximab, notify your doctor immediately or, if severe, call an ambulance:

  • Itching
  • A rash
  • Swelling of your hands, mouth or face
  • Difficulty breathing
  • Trouble swallowing

During your infusion, or not long after, you may suffer what some sort of infusion reaction. The signs of this include chest pain and discomfort, vomiting or nausea, redness on your upper chest arms, neck or face, back pain, uneven or rapid heartbeat and difficulty breathing. If this occurs, then immediately make your nurse or doctor aware.

There is a chance of you having a gastrointestinal perforation. The signs to look out for are vomiting of material looking like ground coffee, bloody and black tarry stools or severe stomach and abdominal pains and cramps. Again, notify your doctor and seek immediate medical attention if this occurs at any time.


Siltuximab is not a prescription medication that you can take home, so you will not need to know how to store it. Instead, you will only be given the drug in a medical setting by a trained nurse or doctor.


If taken regularly and in a safe medical environment, Siltuximab is a potentially very effective way to treat and improve the quality of life for someone suffering from MCD. However, under no circumstance should you attempt to buy or use Siltuximab on your own. It should only ever be prescribed following an in-depth analysis of your existing medical condition as well as your dietary intake. Siltuximab is known to interact with a wide variety of different foods and drugs, and your doctor is best placed to come to a good understanding as to whether this is the correct drug for you.

If you are on a course of Siltuximab then you need to commit to attending each one of your appointments every three weeks. Failure to do so will reduce the effectiveness of the course of treatment. Your doctor will make you fully aware of any potential side effects that can occur whilst taking Siltuximab, and they can advise you on signs to look out for and ways to help reduce any unwanted effects.


Last Reviewed:
February 01, 2018
Last Updated:
April 05, 2018