Cosentyx is a prescription drug that’s used to treat certain inflammatory conditions, such as plaque psoriasis. Cosentyx can cause side effects that range from mild to serious. Examples include infections, diarrhea, and hives.
Cosentyx is used in adults and some children to treat:
- moderate to severe plaque psoriasis that may benefit from phototherapy (light treatment) or systemic treatment (medication that works throughout your body)
- an active* form of arthritis, such as:
- psoriatic arthritis (arthritis that affects the skin and joints)
- ankylosing spondylitis (rare form of arthritis that mostly affects your spine)
- non-radiographic axial spondyloarthritis with inflammation that can be measured with certain tests
- arthritis related to enthesitis (inflammation in areas of your bones where tendons and ligaments attach)
The active ingredient in Cosentyx is secukinumab. (An active ingredient is what makes a drug work.) The drug comes as an injection given under the skin.
Keep reading to learn about the common, mild, and serious side effects that Cosentyx can cause. For a general overview of the drug, including details about its uses, see this article.
* “Active” means your condition is causing symptoms.
Cosentyx can cause rare but serious side effects. In studies, these rare side effects included:
- Serious infection. Using Cosentyx may make it harder for your immune system to fight infections, including tuberculosis (TB). Your doctor will check you for TB before and during your Cosentyx treatment. Your risk for a serious infection may be higher if you have a chronic (long lasting) infection or have had recurring (repeating) infections.
- Inflammatory bowel disease (IBD) or IBD flare-ups. IBD is a group of conditions that cause inflammation (swelling or damage) in certain parts of your digestive system. Examples include Crohn’s disease and ulcerative colitis. If you have IBD, your doctor will watch you closely during Cosentyx therapy or choose a different treatment. Tell your doctor if you have IBD, even if it’s in remission (periods of time with no IBD symptoms).
- Anaphylaxis. Anaphylaxis is a life threatening allergic reaction that requires immediate medical care. Symptoms of anaphylaxis can include trouble breathing or swelling in your face or throat. If you experience these symptoms, call 911 or your local emergency phone number, or get medical care right away.
Cosentyx may cause other mild or serious side effects. To learn more, see the next sections.
Cosentyx can cause mild side effects. These may include:
- cold sores (lip, mouth, or gum infection caused by herpes simplex virus)
- cold symptoms, such as cough, congestion, runny nose, or sore throat
* To learn more about this side effect, see the “Side effects explained” section below.
In most cases, these side effects should be temporary. And some may be easily managed, too. But if you have any symptoms that are ongoing or that bother you, talk with your doctor or pharmacist. And don’t stop using Cosentyx unless your doctor recommends it.
Cosentyx may cause other mild side effects, too. See the prescribing information for Cosentyx to learn more.
In rare cases, Cosentyx may cause serious side effects. Before starting treatment, talk with your doctor about your risk for serious side effects from this drug.
Serious side effects of Cosentyx may include:
- bacterial, fungal, or viral infection*
- inflammatory bowel disease (IBD)*
- allergic reaction, including anaphylaxis*
* To learn more about this side effect, see the “Side effects explained” section below.
See the “Side effects explained” section below to learn more about these serious side effects.
If you experience side effects of Cosentyx that feel serious or life threatening, call 911 or your local emergency phone number, or get emergency medical care.
Get answers to some frequently asked questions about Cosentyx’s side effects.
Is fatigue a side effect of Cosentyx?
However, fatigue is a side effect of methotrexate (Trexall, Rasuvo, RediTrex, Otrexup), which you may use with Cosentyx. Fatigue can also be a symptom of psoriatic arthritis or other conditions that Cosentyx treats.
If you experience fatigue that bothers you, talk with your doctor. They’ll check your overall health and review your medications. Don’t stop or change your Cosentyx treatment unless your doctor recommends it.
Can the Cosentyx injection cause side effects?
It’s possible. Injection-site reactions weren’t seen in studies, but in general, injected drugs such as Cosentyx may cause certain side effects. An example is skin irritation.
Cosentyx comes as a solution that’s given as an injection under your skin. In some cases, the injection may cause mild or temporary swelling, discoloration, or pain at the injection site.
It’s also important to note that the Cosentyx Sensoready Pen and prefilled syringes have removable caps that contain latex. If you have a latex allergy, you may be sensitive to these forms of the drug. Talk with your doctor about your risk for injection-site reactions with Cosentyx. You may need to receive Cosentyx injections with a latex-free syringe in your doctor’s office instead of giving yourself the injections at home.
If you’re having trouble injecting Cosentyx, ask your doctor or pharmacist for tips. And for more help with self-injecting Cosentyx, see these instructions for use.
Can Cosentyx cause weight loss?
No, it’s unlikely that Cosentyx causes weight loss. This side effect wasn’t seen in studies of Cosentyx.
Weight loss is a common side effect of apremilast (Otezla), which is also used to treat plaque psoriasis and psoriatic arthritis in adults.
Additionally, weight loss may be a symptom of an infection. And infections are a possible side effect of Cosentyx.
If you have unexplained weight loss while using Cosentyx, talk with your doctor. They’ll check your overall health and review your medications. Don’t stop or change your Cosentyx treatment unless your doctor recommends it.
Can depression be a side effect of Cosentyx?
Other drugs used to treat your condition may cause depression. Examples of these drugs include:
- Brodalumab (Siliq), which treats plaque psoriasis and may raise your risk for depression and suicidal thoughts or behaviors. This drug works the same way in your body as Cosentyx.
- Corticosteroids such as prednisone (Rayos), which treat psoriatic arthritis and other autoimmune diseases. Corticosteroids may cause mood changes and depression, especially when they’re taken too long or in high doses.
In addition, autoimmune diseases such as psoriasis are linked with depression and mental health conditions.
Depression is a serious condition that shouldn’t be ignored. If you think you have depression or another mental health condition, call your doctor as soon as possible. Symptoms of depression may include anxiety, mood changes, loss of appetite, or feeling angry or irritable.
I’m having some hair loss. Could Cosentyx be causing it?
No, Cosentyx shouldn’t cause hair loss. Hair loss wasn’t seen in studies of Cosentyx.
But hair loss is a side effect of methotrexate (Trexall, Rasuvo, RediTrex, Otrexup), which is sometimes used with Cosentyx. And in rare cases, other biologic drugs such as etanercept (Enbrel) and adalimumab (Humira) may cause hair loss. (Cosentyx is also a biologic drug, which is a drug made from living cells.)
Also, plaque psoriasis can form itchy patches on your scalp. Itching can cause hair loss. But once the patches improve, your strands should grow back.
If you’re concerned about hair loss while using Cosentyx, talk with your doctor.
Learn more about some of the side effects Cosentyx may cause.
Bacterial, fungal, or viral infections
Mild infections are a common side effect of Cosentyx. Examples include upper respiratory infections (such as the common cold) and cold sores. In most cases, these infections should go away on their own. You’ll likely only need treatment to relieve your symptoms.
In rare cases, Cosentyx can cause serious infections. These may include:
You’ll likely need treatment to clear these infections.
Note: TB is a rare but serious bacterial infection that primarily affects the lungs. Your doctor will check you for TB before and during your Cosentyx treatment. Tell your doctor if you’ve had TB in the past, too. Drugs that affect your immune system, such as Cosentyx, may cause a latent TB infection (TB that’s in your body but isn’t causing symptoms) to become active again.
What might help
Here are a few steps you can take to help prevent infection while using Cosentyx:
- Wash your hands often (use hand sanitizer if soap and water aren’t available).
- Avoid crowds during cold and flu season.
- Stay up to date on vaccines (but see note below for certain exceptions).
- Eat a balanced diet.
- Keep your doctor and lab appointments.
- Contact your doctor if you feel sick or have a fever.
Call your doctor if you have any symptoms of infection, even if they seem mild. Your doctor will check for a serious infection and treat it if needed.
In some cases, your doctor may stop your Cosentyx treatment until your infection has cleared. But don’t stop using Cosentyx unless your doctor recommends it.
Note: Because Cosentyx may weaken your immune system, you shouldn’t get live vaccines during your treatment. Live vaccines contain a weakened form of a virus or bacteria, and they could cause infection in someone with a weakened immune system. Examples of live vaccines include those for smallpox and chickenpox, and the measles, mumps, rubella (MMR) vaccine.
Before starting Cosentyx, talk with your doctor about any vaccines you may need.
Inflammatory bowel disease
What might help
Before starting Cosentyx, tell your doctor if you have Crohn’s disease, UC, or another type of IBD. It’s important to mention your IBD even if it’s in remission (you’re not currently experiencing symptoms). Your doctor may monitor you more closely during your treatment, or they may choose another treatment for your condition.
While using Cosentyx, watch for IBD symptoms. Tell your doctor right away if you have new or worsening:
- belly pain or cramping
- bloating or gas
- blood or mucus in your stool
- mouth ulcers
Before starting Cosentyx, talk with your doctor about your IBD risk and symptoms to watch for.
Diarrhea is a common side effect of Cosentyx. However, diarrhea is also a symptom of inflammatory bowel disease (IBD), which is a rare but serious side effect of Cosentyx.
What might help
Diarrhea that’s not caused by IBD should go away in a few days or couple of weeks.
Until then, stay hydrated and consider following the BRAT diet. (BRAT stands for bananas, rice, apples, and toast.) These are bland foods that shouldn’t upset your digestive system, and they can bulk up your stools. You can also ask your doctor if it’s safe to use over-the-counter diarrhea treatments.
In some cases, diarrhea may be a sign of IBD, which is a serious side effect of Cosentyx. Call your doctor if your diarrhea doesn’t go away or gets worse. And call them right away if you see blood or mucus in your stool.
Two forms of Cosentyx, the Sensoready Pen and prefilled syringes, have removable caps that contain latex. If you have a latex allergy, you may be sensitive to these forms of the drug.
Allergic reaction to latex wasn’t tested in studies of Cosentyx, so it’s unclear how often this may occur.
What might help
If you have a latex allergy, talk with your doctor before using Cosentyx. You may need to receive Cosentyx injections with a latex-free syringe in your doctor’s office instead of giving yourself the injections at home. Or your doctor may prescribe a different treatment for your condition.
If you have a mild latex allergy and use the pen or prefilled syringe to self-inject at home, watch for symptoms of allergic reaction. These symptoms could include hives or skin rash. If you have side effects that feel serious or life threatening, call 911 or your local emergency phone number, or get emergency medical care.
In rare cases, Cosentyx may cause hives (itchy welts on your skin). Hives are a common symptom of allergic reaction.
What might help
With mild allergic reactions, hives usually go away without treatment. If you’re uncomfortable, try cold compresses (unless cold makes your hives worse) or calamine lotion.
But if your hives are severe, or if you have other symptoms of an allergic reaction (such as swelling), contact your doctor. They may prescribe treatment such as an antihistamine. If your symptoms feel life threatening, call 911 or your local emergency phone number, or get medical care right away.
If your doctor confirms you’re having an allergic reaction, they may stop your Cosentyx treatment. But don’t stop taking this drug unless your doctor recommends it.
Like most drugs, Cosentyx can cause an allergic reaction in some people. Symptoms can be mild or serious and can include:
- skin rash or hives
- flushing (temporary warmth, redness, or deepening of skin color)
- swelling under your skin, typically in your eyelids, lips, hands, or feet
- swelling of your mouth, tongue, or throat, which can make it hard to breathe
What might help
If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. . To help manage your symptoms, they may suggest an over-the-counter antihistamine that you swallow, such as diphenhydramine (Benadryl), or a product you apply to your skin, such as hydrocortisone cream.
If your doctor confirms that you had a mild allergic reaction to Cosentyx, they’ll decide if you should continue using it.
If you have symptoms of a severe allergic reaction, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.
Keeping track of side effects
During your Cosentyx treatment, consider keeping notes on any side effects you’re having. Then, you can share this information with your doctor. This is especially helpful to do when you first start taking new drugs or using a combination of treatments.
Your side effect notes can include things like:
- what dose of drug you were taking when you had the side effect
- how soon after starting that dose you had the side effect
- what your symptoms were from the side effect
- how it affected your daily activities
- what other medications you were also taking
- any other information you feel is important
Keeping notes and sharing them with your doctor will help your doctor learn more about how Cosentyx affects you. And your doctor can use this information to adjust your treatment plan if needed.
Cosentyx may not be right for you if you have certain medical conditions or other factors that affect your health. Talk with your doctor about your health history before you take Cosentyx. Factors to consider include those listed below.
Inflammatory bowel disease. If you have a type of inflammatory bowel disease (IBD) such as Crohn’s disease or ulcerative colitis, talk with your doctor before using Cosentyx. This drug may cause serious IBD flare-ups. Your doctor may monitor you closely during your treatment, or they may choose another treatment for your condition. While using Cosentyx, tell your doctor right away about any new or worsening IBD symptoms, including bloating, gas, or blood or mucus in your stools.
Allergy to latex. If you have a latex allergy, talk with your doctor before using Cosentyx. Two forms of Cosentyx, the Sensoready Pen and prefilled syringes, have removable caps that contain latex. If you have a latex allergy, you may be sensitive to these forms of the drug. Ask if you should receive Cosentyx injections with a latex-free syringe in your doctor’s office or if you can give yourself injections at home.
Infection. If you have an infection, your doctor may need to treat it before you start using Cosentyx. This is because the drug can raise your risk for infections, including tuberculosis (TB). Tell your doctor if you’ve had TB before. Your doctor will check you for TB before and during your Cosentyx treatment.
Allergic reaction. If you’ve had an allergic reaction to Cosentyx or any of its ingredients, you shouldn’t take Cosentyx. Ask your doctor what other medications are better treatment options.
Alcohol and Cosentyx
If you drink alcohol, it should be safe to drink during Cosentyx treatment.
However, alcohol can damage your liver. A drug that’s used with Cosentyx, methotrexate (Trexall, Rasuvo, RediTrex, Otrexup), can also harm your liver. Drinking alcohol with methotrexate can raise your risk for liver problems. Therefore, you should avoid alcohol if you’re using methotrexate to treat your condition.
If you drink alcohol, talk with your doctor about how much is safe for you to drink with your condition and treatment plan.
Pregnancy and breastfeeding while using Cosentyx
It’s unknown if Cosentyx is safe to use during pregnancy or while breastfeeding.
If you’re pregnant or breastfeeding, or planning to become pregnant or to breastfeed, talk with your doctor before using Cosentyx.
Cosentyx may help relieve symptoms of plaque psoriasis, psoriatic arthritis, or other types of arthritis. In some people, Cosentyx may cause mild side effects. In rare cases, it could also cause an infection or other serious side effects.
If you have questions or concerns about Cosentyx’s side effects, talk with your doctor or pharmacist. They can provide information to help you manage side effects. Here are a few example questions to get you started:
- Am I at risk for any serious side effects?
- If I get tuberculosis (TB) while using Cosentyx, can it be treated?
- If I develop inflammatory bowel disease (IBD) while using Cosentyx, will it go away when I stop the drug?
- What can I do to help prevent infection while using Cosentyx?
To learn more about Cosentyx, see these articles:
- All About Cosentyx
- Cosentyx and Cost: What You Need to Know
- Cosentyx Dosing Details
- Cosentyx: How It’s Used to Treat Psoriasis
To get information on different conditions and tips for improving your health, subscribe to any of Healthline’s newsletters. You may also want to check out the online communities at Bezzy. It’s a place where people with certain conditions can find support and connect with others.
Cosentyx may prevent certain vaccines, such as the flu shot or COVID-19 vaccines, from working as well as they should. If possible, you should get a flu shot or COVID-19 vaccine at least 2 weeks before you start using Cosentyx.
However, if you’re already taking the drug, you may still benefit from these vaccines. Talk with your doctor to learn more.
You shouldn’t get any live vaccines, such as the FluMist (nasal spray) flu vaccine, while using Cosentyx. (Live vaccines contain a weakened form of the virus or bacteria.)
Before starting your Cosentyx treatment, talk with your doctor about any vaccines you may need.The Healthline Pharmacist TeamAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.
Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.