Pyzchiva Side Effects: What to Expect and When to Call Your Doctor

Like all biologic medications, Pyzchiva (ustekinumab-ttwe) can cause side effects. Most side effects are mild and manageable — but some are serious and require immediate medical attention. Understanding what to watch for helps you stay safe and get help quickly when you need it.

This guide covers the most important side effects associated with Pyzchiva, based on clinical trial data and the FDA prescribing information.

Common Side Effects of Pyzchiva

These side effects are reported by a meaningful percentage of patients in clinical trials and are generally mild to moderate in severity:

• Upper respiratory infections: Nasal congestion, sore throat, and runny nose are among the most frequently reported side effects. These are usually mild and resolve on their own.
• Headache: A common side effect, typically manageable with over-the-counter pain relievers. Notify your doctor if headaches are severe or accompanied by other symptoms.
• Fatigue/tiredness: Some patients feel tired, particularly around the time of injection.
• Injection site reactions: Redness, pain, or swelling at the injection site can occur. Rotating injection sites can help minimize this.
• Gastrointestinal symptoms: Nausea, vomiting, diarrhea, and stomach pain. Vomiting was reported in at least 3% of patients receiving Pyzchiva for Crohn's disease induction.
• Itching (pruritus): Some patients experience itching, particularly in the early weeks of treatment.
• Urinary tract and vaginal yeast infections: Because Pyzchiva modifies immune function, some patients may be more susceptible to certain infections like UTIs and vaginal yeast infections.
• Sinusitis and bronchitis: Upper respiratory infections of the sinuses and bronchial tubes occur in some patients. Most resolve with standard treatment.
• Joint pain (arthralgia): Some patients experience joint pain as a side effect, though for many the joint pain from their underlying psoriatic arthritis is the main concern that Pyzchiva is treating.

Serious Side Effects — Call Your Doctor Immediately

These side effects are less common but can be life-threatening. Contact your healthcare provider or go to the emergency room immediately if you experience any of the following:

• Serious infections: Pyzchiva lowers your immune system's ability to fight infections. Serious bacterial, fungal, viral, and mycobacterial infections (including tuberculosis) have been reported. Signs include: fever, chills, muscle aches, persistent cough, shortness of breath, weight loss, skin sores that won't heal.
• Tuberculosis (TB) reactivation: You should be screened for latent TB before starting Pyzchiva. If you develop TB symptoms during treatment, stop Pyzchiva and notify your doctor immediately.
• Posterior Reversible Encephalopathy Syndrome (PRES): A rare but serious brain condition. Symptoms include sudden headache, confusion, vision changes, and seizures. If PRES is suspected, Pyzchiva should be discontinued immediately.
• Malignancy: Ustekinumab products may increase the risk of certain cancers. The FDA prescribing information notes this risk. Discuss your personal cancer risk history with your doctor before starting Pyzchiva.
• Serious allergic reactions: Symptoms include: hives, swelling of the face/lips/tongue/throat, difficulty breathing, feeling faint, or chest pain. Stop using Pyzchiva and call 911 or go to the emergency room immediately.
• Interstitial pneumonitis: Rare cases of interstitial lung disease have been reported with ustekinumab products, presenting as cough, shortness of breath, and interstitial infiltrates on imaging. This has occasionally required hospitalization and corticosteroid treatment.

Vaccines and Pyzchiva: What You Need to Know

Because Pyzchiva affects your immune system, there are important vaccine considerations:

• No live vaccines: Do not receive live vaccines while on Pyzchiva. This includes vaccines such as MMR, Varicella, Yellow Fever, and the nasal flu vaccine.
• BCG vaccine: Do not receive BCG vaccine for one year before starting Pyzchiva or for one year after stopping it.
• Non-live (inactivated) vaccines: You can receive flu shots and other inactivated vaccines while on Pyzchiva, though they may be less effective than usual. Try to stay up to date on all recommended vaccines before starting treatment.

Storing Pyzchiva Safely

Keep Pyzchiva refrigerated at 36°F to 46°F (2°C to 8°C). Do not freeze. Prefilled syringes can be stored at room temperature (up to 86°F/30°C) for up to 60 days if needed, but must not be returned to the refrigerator more than once. Keep in the original carton to protect from light. For information on drug interactions, see our guide: Pyzchiva Drug Interactions: What to Avoid.