infliximab (in FLICKS ah mab)
What is infliximab?
Infliximab belongs to a new class of drugs known as monoclonal antibodies. This particular drug blocks the activity of an inflammatory chemical in the tissue called tumor necrosis factor (TNF). Excessive TNF seems to lead to increased inflammation and damage in the tissues in disorders like Crohn’s disease and rheumatoid arthritis. Because infliximab blocks TNF, it is known as “anti-TNF”.
What is it used for?
Infliximab is used for the treatment of patients with moderate to severe Crohn’s disease for whom conventional therapy has not been effective. It is also used to treat Crohn’s patients who have fistulas which are sinus-like tracts that most often run from the bowel to the perianal area and produce intermittent damage. Infliximab is not a cure for Crohn’s disease.
How is it given?
Infliximab is given by intravenous infusion over a two-hour period. The dosage is determined by the patient’s weight and the physician’s determination of how many milligrams per pound of weight is appropriate.
Are there interactions with food or beverages?
There is no known interaction between this drug and any food or beverage.
Are there interactions with other drugs?
There are no known interactions between infliximab and other drugs including those that a Crohn’s patient may be taking which include prednisone, Asacol, Pentasa, Azulfidine, Imuran and 6-MP (Purinethol).
Is there a problem if I have another disorder or disease?
At times, a drug may have a different or enhanced effect when other diseases are present. At other times, the drug may worsen or effect another disease. At present, there is no known adverse effect of this drug on other diseases.
What about allergies?
Allergies are known to occur with infliximab infusion. In clinical testing, about 7% of patients receiving their first infusion had a reaction. About 10% of patients had a reaction on their second infusion. Most of these were considered minor (see Side Effects). About 1% had what were considered more serious reactions, including hives, blood pressure drop or chest pain. Patients who developed certain antibodies in their blood after the first infusion were more likely to develop a reaction on subsequent infusions. The effect of infliximab in pediatric patients and the elderly is unknown.
What if I’m pregnant, considering pregnancy or breast-feeding?
Most females now know that, if possible, no drug, including alcohol, should be taken during pregnancy or lactation. The potential danger, of course, is an injury to the fetus or baby. However, some drugs are much safer than others in this regard. So, the FDA has a grading system for each drug which reflects what is known medically. It ranks drugs from A, where medical studies show no evidence for danger to the fetus or mother, to B, C, D and X, where the medical evidence indicates increasing risk to the fetus which eventually outweighs any benefit to the mother. Infliximab is ranked B. Always consult your physician before taking any drug during or when planning pregnancy.
Most physicians will not want female patients who are already pregnant or trying to become pregnant to receive this drug. Further, males who are trying to father a child generally should not receive the drug. Nursing mothers should not receive this drug as its transmission in mother’s milk and effect on the baby are unknown.
What are the effects on sexual function?
There are no known adverse effects of infliximab on sexual function.
Are there other precautions?
Immune antibodies are proteins that the body may produce when another foreign protein is infused. This is, of course, what happens when you are vaccinated. With infliximab, certain antibodies may develop which may make an allergic reaction more likely with subsequent infusions.
Infections can occur after an infusion since the drug does block the body’s response to infection and inflammation.
Malignancies have not been clearly seen to develop with infliximab. Long-term Crohn’s patients who take other immune suppression drugs may have a very slight increase in a lymphoid tumor, called lymphoma. Infliximab is not known to contribute to any such risk.
How long is it safe to take infliximab?
Infliximab has been released by the FDA for use in 1998. It is a new drug, so long-term effects are not known. During clinical trials, long-term problems have not been seen.
How about side effects?
Adverse reactions can occur with any drug, even over-the-counter medications. Minor reactions generally go away on their own but if they persist, the patient should contact the physician. For major reactions that may occur after returning home from the infusion, the patient should contact the physician immediately.
There are a number of side effects that can occur after an infusion. These include:
- respiratory infection
- skin rash/itching
- muscle aches
- abdominal pain
- shortness of breath
- chest pain
Patients should report all side effects to the physician or to the center where the infusion has been given.
A physician’s comment…
Gastroenterologists are cautiously excited about infliximab and similar drugs that should be available in the near future. Up to this time, there were only four classes of drugs available for treating Crohn’s disease, steroids (prednisone), 5 aminosalicylates (Asacol, Pentasa, sulfasalazine), immune modulators (Imuran, Purinethol or 6-MP) and antibiotics. This drug is an entirely new class of drug. Physicians are hopeful that these new drugs offer significant benefits for patients with difficult Crohn’s disease.