If you live with Crohn's disease, your doctor might recommend treatment with biologics. These medications help ease symptoms and achieve remission. They also reduce inflammation and can prevent long-term damage. Like any treatment, they can cause side effects.
Most Common Side Effects
Biologic medications are live antibodies produced in a lab. They help block certain proteins in the body that cause inflammation. They work by modifying your immune system. They also work in a more targeted way than many traditional treatments because they focus on specific proteins. But they can still cause side effects. Most are mild and easy to manage. Here are some of the most common ones.
Reactions from the needle
If your biologic is subcutaneous, meaning you give it with a small needle under the skin, you might experience the following side effects where the needle went in your skin:
- Redness
- Mild pain
- Itching
- Tenderness
- Slight swelling
These reactions can last from a few hours to a couple of days. They are very common and usually not a cause for concern.
Reactions during or after an infusion
If you are given the biologic intravenously (by IV) at an infusion center, you might experience:
- Headaches
- Low blood pressure or dizziness
- Flushing of the face
- A feeling of warmth
- Nausea
One advantage of infusion treatment is that it takes place in specialized centers. If you have any symptoms, questions, or concerns, the medical staff at the center can help.
Fatigue
It's common to feel general tiredness when using biologic medications for Crohn's disease. It usually appears in the first few weeks as your body adjusts to the treatment.
To ease fatigue, you can:
- Ask your doctor for a blood test to figure out if you need iron or vitamins
- Stay active with gentle or low-impact exercise, meditation, or therapy
- Avoid caffeine and screens in the evenings for better sleep
Mild infections
Biologic medications calm a specific part of your immune system to control inflammation. Because of this, your body might have fewer defenses against some germs.
This can raise your chances of mild viral, bacterial, and fungal infections, such as:
- Colds
- Sinusitis
- Urinary tract infections
Gastrointestinal issues
You might experience nausea, diarrhea, or abdominal pain. In people with Crohn's disease, it can be hard to tell if it's a temporary side effect or a flare-up.
Headaches
They are usually mild and can be managed with common pain relievers (approved by your doctor).
Muscle or joint pain
This can happen after receiving a dose but tends to improve after a few hours or days.
Most of the common side effects of biologic medications appear at the start of treatment and get better over time as the body gets used to the medicine.
Tips for Easing Side Effects
Once you start treatment with biologics, there are simple steps that can help you manage the most common side effects.
For reactions where the needle went in
- Apply a cold compress or ice pack before and after the shot.
- Check with your doctor to see if you can take pain medication to ease discomfort.
- Change the spot where the needle goes in for each dose.
For fatigue
- Drink more water.
- Avoid alcohol.
- Get enough sleep.
- Choose light, nutrient-rich meals.
- Walk or meditate to reduce stress.
For headaches
- Stay hydrated.
- Rest in a quiet, dark place.
- Apply cold and hot compresses to your head or neck.
- Gently massage your head or neck.
- Drink caffeine only in the morning.
- Talk to your doctor about which pain medications are safe for you.
For stomach discomfort
- Avoid heavy meals for 24 hours after a dose.
- Choose easy-to-digest foods, like gelatin.
- Rest and avoid sudden movements that may worsen nausea.
- Drink lemonade, ginger ale, peppermint tea, and plenty of water.
- Avoid strong smells and other nausea triggers.
To prevent infections
- Wash your hands frequently.
- Avoid close contact with sick people.
- Stay up to date with your vaccines, as recommended by your doctor.
When to Call Your Doctor
Call your doctor if you have symptoms of infection or other less common side effects, such as:
- Persistent fever or a fever higher than 100.4 F
- Difficulty breathing
- Severe swelling of the face, lips, or throat
- Chest pain
- Widespread hives
- Severe or bloody diarrhea
- Persistent vomiting
- Clear signs of infection, such as severe pain when urinating, cough with thick phlegm, or worsening skin sores
- Confusion, severe dizziness, or fainting
- Yellowing of the skin or eyes (jaundice)
These symptoms require immediate medical attention.
Can You Use Biologics if You Have Cancer?
The latest evidence shows that if you have Crohn's disease or ulcerative colitis and have had cancer, you can use these medications safely with proper management.
If you currently have cancer, talk to your doctor to figure out if biologics are suitable for your immune system at this time.
Get Ready for Biologic Treatment
Take these steps before starting treatment to help you feel more prepared and lessen some side effects.
Get a complete health panel, which may include blood tests, tuberculosis (TB) tests, hepatitis screening, and a review of your vaccines. This can help spot certain risks early, such as infections or low nutrient levels that can cause fatigue.
Keep a calendar where you can write the dates of your shots or infusions, appointment reminders, and your symptoms. This makes it easier to track this information and communicate with your medical team.
Prepare a "biologic kit" with basic items like alcohol wipes, cold packs, a notebook, and something to entertain yourself during treatment.
How Your Medical Team Can Help
Your medical team plays a key role in managing the side effects of biologic medications. They are with you before, during, and after treatment so you feel safe, informed, and supported at every stage. They can help you with the following:
Education and training:
- Teach you how to use the autoinjector
- Explain what to expect after each dose
- Answer your questions about normal side effects or warning signs
Medication adjustments if you have side effects:
- Adjust the dose
- Change the frequency
- Switch you to another biologic
Continuous monitoring:
- Run blood tests
- Watch for signs of infection
- Check your progress and response to treatment
Emotional support:
- Provide support from specialized nurses, especially during your first treatments
If side effects don't improve or the treatment doesn't work as expected, your doctor may consider changing the medication. This is common and part of finding the best option for you. Make sure to tell your doctor about your symptoms and keep a record of them to help you make a decision.
Show Sources
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