Side effects of Humira – What should I watch out for?

Humira is a so-called monoclonal antibody and, like any effective drug, has side effects. Antibodies can bind certain structures in the body in a targeted way. Mostly these are immune system structures, to suppress the body’s immune response. Humira was initially approved for the treatment of rheumatoid arthritis and is now used for a wide variety of chronic inflammatory diseases. For therapy for inflammatory bowel disease Crohn's disease and ulcerative colitis, approval represented a major innovation, particularly for those patients for whom well-known medications had little or no success.

Conventional medications also work by suppressing the immune system (immunosuppressants), but in a less targeted and much broader way. They have the great advantage that they have been used for a long time so there is a great wealth of experience regarding their use and side effects. The disadvantage is often their limited effectiveness.

Antibody therapy, on the other hand, plays an increasingly important role in the treatment of autoimmune and cancer diseases, since it is often significantly more effective. Compared to other immunosuppressants, they usually show a faster onset of action. Their side effect profile differs in part from the previous drugs.

Which side effects are of particular importance?

To understand which side effects can be caused by therapeutic antibodies like Humira, you should keep the mode of action in mind. The target of the active substance adalimumab, which is contained in Humira, is the so-called tumor necrosis factor (short: TNF-α). It is a messenger for our immune system - which is widespread and effective: it affects almost all cells and is an essential mediator of immune and inflammatory reactions.

TNF-α blockers are therefore counted among the drugs that aim at the suppression of the immune system (immunosuppressants). That is why one of the side effects can be infections.

Tuberculosis must therefore be excluded before starting therapy with Humira. However, ongoing therapy may also have to be interrupted in the case of various infections, which are initially less serious, so that the body's immune system can react appropriately to pathogens. Serious infections are very rare overall, but are potentially dangerous.

Tab.: Overview of the side effects of Humira

Side effects: Skin

Cases of newly emerging psoriasis and cases of exacerbation of existing psoriasis have been observed with treatment using TNF-α blockers, including Humira. If the condition is severe, this can lead to the treatment with Humira having to be stopped.

Aside from that, rashes, itching and inflammatory changes in the skin are frequent side effects.

Side effects: Lungs, heart and intestines

One of the common side effects is** coughing**, and occasional shortness of breath can also occur. Attention should be paid to infections of the upper and lower respiratory tract, which can occur frequently under immunosuppressive therapy.

The general rule: Symptoms of any infection (e.g. fever, wounds, fatigue, dental problems) must urgently be clarified by a doctor under therapy with immunosuppressants.

The heart is only occasionally or rarely affected by side effects, such as increased heart rate and irregular heartbeat. With existing heart failure Humira cannot always be used due to the possible sometimes severe impairments of the heart.

The gastrointestinal tract can frequently show a reaction to the drug. Among others, diarrhea, abdominal pain, nausea and gastrointestinal bleeding have been reported. Serious side effects such as an intestinal wall breakthrough are rare.

Side effects: Eyes

The eyes can occasionally experience side effects such as conjunctivitis or increased intraocular pressure. In rare cases, therapy with TNF-α blockers has been reported to cause a new occurrence or worsening of existing multiple sclerosis. This disease is often noticeable when it first appears as an optic nerve inflammation due to a one-sided reduction in visual acuity, loss of visual field and pain during eye movements.

Side effects: Teeth

Toothache, bleeding gums and itching can occur in the mouth. It is important that teeth or the oral cavity can also be the starting point for an infection that should be avoided with immunosuppression. A toothache must therefore always be treated quickly. Before an intervention at the dentist, they should also be informed about your use of Humira.

Side effects: Weight changes with Humira

An increase in weight can be a (common) side effect of Humira. Weight loss is not one of the specific side effects of Humira. Under certain circumstances, however, this is a symptom of an infection or cancer and should therefore always be clarified immediately by a doctor.

Can Humira cause cancer?

The cells of the human immune system not only fight pathogens, but also cancer cells. For this reason, the new immunosuppressants such as Humira have been suspected of causing an increased risk of tumor diseases since their development.

However no definitive statement is possible on this as of yet. Since the class of TNF-α blockers is still very new, there is no long-term data. It also needs to be studied for a larger patient population. Case reports from individual patients in which tumor diseases have been reported after such therapy must be considered. However, they cannot easily be extrapolated to the general public. The highly active, inflammatory underlying diseases among the treated patients increase the risk of some tumor diseases without any therapy, which further complicates the assessment.

However, from all previous studies on biologica therapy for patients with rheumatoid arthritis, Crohn's disease and ulcerative colitis it can be said that it **no evidence of an increased risk of cancer **exists.

The information on side effects listed is explicitly not exhaustive; a complete list can be found in the package insert or the manufacturer's specialist information. The aim here is to give an overview of the undesirable effects of Humira that concern many patients. If a side effect (described or unknown) is suspected due to a medication, the doctor must be informed.

When Humira is no longer effective

Some patients can develop resistance to therapy with TNF-α blockers. The cause is probably the formation of inactivating antibodies by your own immune system. These bind to the individual spatial structure of the active ingredient.

If such a loss of effectiveness is probable, i.e. other causes for the lack of effectiveness are excluded, patients can switch to a different TNF-α blocker with another active ingredient. However, the dosage may need to be adjusted or increased. The monitoring of such therapy always belongs in the hands of a specialist and should also be checked at regular intervals. They can create an individual medication and dosage plan for each patient.

Humira lost its patent protection in autumn 2018. At the end of the patent protection, competition from various manufacturers began, which caused prices to drop. According to data from the GKV drug index 2016, Humira was actually the drug with the highest sales. Now there are several approved successor products with the same active ingredient (generics) on the market.