Approved indications (FDA):

• Maintenance treatment of moderately to severely active Crohn’s disease in adults after treatment with an intravenous infliximab product.
• Maintenance treatment of moderately to severely active ulcerative colitis in adults after treatment with an intravenous infliximab product.

Off-label uses:

• Unlike intravenous infliximab, Zymfentra is not approved for rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, or psoriasis, and there are no well-established off-label indications yet; any off-label use would generally extrapolate from IV infliximab experience and has limited direct evidence.

Efficacy expectations:

• Most symptom improvement begins during the IV infliximab induction phase (first 6–10 weeks); Zymfentra is started around week 10 to maintain or deepen that response.
• In 54‑week maintenance trials, 63% of Crohn’s disease patients and 43% of ulcerative colitis patients on Zymfentra were in clinical remission versus 30% and 21% on placebo, respectively.
• Compared with IV infliximab and other TNF blockers, Zymfentra offers similar expected control of disease activity with the convenience of at‑home subcutaneous dosing and more stable trough levels, without new major safety signals in trials.

Typical adult dosing and schedule:

• Zymfentra is used only as maintenance therapy after an induction course with an intravenous infliximab product; it is not used for the initial IV induction.
• The recommended adult maintenance dose is 120 mg injected under the skin once every 2 weeks, starting at Week 10 after the first IV induction dose.
• For patients already on IV infliximab maintenance, the first Zymfentra dose is given in place of the next scheduled infusion, then every 2 weeks thereafter.
• Dosing is fixed (not weight‑based), and safety and effectiveness have not been established in children under 18 years.

How to take the medicine:

• Zymfentra is for subcutaneous (under‑the‑skin) injection only, using a prefilled pen or syringe in the front of the thighs, abdomen (avoiding 2 inches around the navel), or outer upper arms (by a caregiver).
• Rotate injection sites, keeping at least about 1.2 inches (3 cm) between new and previous sites, and do not inject into skin that is tender, red, bruised, or hardened.
• Keep injections on a regular every‑2‑week schedule, at a time of day that is easy to remember; dosing is not tied to meals.
• Allow the pen or syringe to warm naturally to room temperature (about 30 minutes) before injection, do not shake, and check that the solution is clear and colorless to pale brown without particles.

Special dosing instructions:

• Use Zymfentra exactly as prescribed; do not change the dose or stop the drug without discussing it with your healthcare provider, as stopping may lead to loss of disease control.
• No specific dose adjustments are recommended for kidney or liver impairment, but careful monitoring is advised in patients with significant hepatic disease or other serious comorbidities.

Missed dose:

• If a dose is missed, inject the next dose as soon as possible and then continue dosing every 2 weeks from that new date; do not take two doses on the same day to “catch up.”
• If you are unsure what to do after a missed dose, contact your prescriber or pharmacist for advice before injecting.

Overdose:

• If more than the prescribed amount is injected, or if injections are given too close together, contact your healthcare provider or poison control center right away and watch for signs of infection, allergic reactions, or other unusual symptoms.

Common side effects:

• Very common or common reactions (generally occurring in at least a few percent of patients) include COVID‑19 or other respiratory infections (such as sinus infections, sore throat, or upper respiratory tract infection), headache, joint pain, diarrhea, abdominal pain, high blood pressure, urinary tract infection, injection‑site reactions, dizziness, abnormal liver tests, anemia, and low white blood cell counts.
• Most are mild to moderate and often appear within the first weeks to months of treatment; injection‑site reactions (redness, itching, soreness) are usually short‑lived.

Serious or rare adverse effects (seek immediate care):

• Serious infections, including tuberculosis (new or reactivated), invasive fungal infections (such as histoplasmosis, coccidioidomycosis, candidiasis, aspergillosis, blastomycosis, pneumocystosis), and severe bacterial or viral infections that can spread through the body and be fatal.
• Cancers, particularly lymphomas (including rare hepatosplenic T‑cell lymphoma) and skin cancers, have been reported with TNF blockers, especially when used long term or with other immunosuppressants.
• Severe liver injury (including liver failure), worsening or new congestive heart failure, serious blood disorders (very low red cells, white cells, or platelets), severe allergic or anaphylactic reactions, delayed serum‑sickness–like reactions, demyelinating disorders (such as multiple sclerosis or Guillain‑Barré), stroke, and lupus‑like syndrome.

Warnings and precautions:

• Before starting therapy, patients are typically screened for tuberculosis and hepatitis B, and monitored during treatment for signs of infection, abnormal blood counts, or liver problems.
• It is not known if Zymfentra is safe or effective in people under 18 years; older adults may have a higher risk of serious infections.
• Use with caution in patients with a history of chronic or recurrent infections, TB exposure, demyelinating disease, moderate to severe heart failure, prior malignancy (especially lymphoma or skin cancers), COPD, or significant liver disease.
• Pregnancy: Limited data do not show a clear increase in birth‑defect risk, but TNF blockers cross the placenta, especially in the third trimester; infants exposed in utero should avoid live vaccines for at least 6 months after birth.
• Breastfeeding: Infliximab appears at low levels in breast milk after IV dosing and is mostly broken down in the infant’s gut; there are no direct data for Zymfentra, so the decision to breastfeed should balance the benefits of breastfeeding, the mother’s need for treatment, and potential infant risks.

Overall safety vs similar drugs:

• Zymfentra shares the same main risks as other infliximab products and TNF‑alpha inhibitors; in maintenance clinical trials, its overall safety profile was comparable to placebo and consistent with the known infliximab class profile, with no new safety signals.

How to report side effects and find safety updates:

• Report any concerning symptoms promptly to your prescriber; patients in the United States can also report side effects to the FDA MedWatch program (online or at 1‑800‑FDA‑1088) and to Celltrion USA at the phone number listed in the Medication Guide.

Drug and biologic interactions:

• Using Zymfentra with other biologic immunosuppressants for inflammatory bowel disease (for example, other TNF blockers, vedolizumab, ustekinumab, or JAK inhibitors combined with biologics) is not recommended because it can greatly increase the risk of serious infections and blood problems.
• Concomitant use with conventional immunosuppressants (such as azathioprine, 6‑mercaptopurine, methotrexate, or high‑dose corticosteroids) is common in practice but adds to infection and malignancy risk, so patients on such combinations need close monitoring.
• Zymfentra may normalize cytokine‑suppressed CYP450 enzyme activity, potentially changing blood levels of drugs metabolized by CYP450 (for example, warfarin, cyclosporine, theophylline); dose or level adjustments may be needed after starting or stopping therapy.

Vaccines and infections:

• Patients should be up to date on all recommended vaccines before starting treatment; live vaccines (such as MMR, varicella, some intranasal flu vaccines, and live shingles vaccines) are generally avoided during TNF‑blocker therapy.
• Infants exposed to infliximab in utero should not receive live vaccines for at least 6 months after birth because the drug can persist in their blood and increase infection risk.

Other precautions and conditions requiring caution:

• Screen for and, if needed, treat latent tuberculosis and hepatitis B before starting Zymfentra; consider risks carefully in people with a history of recurrent or chronic infections.
• Use caution or consider alternatives in patients with moderate to severe heart failure, demyelinating diseases (such as multiple sclerosis or Guillain‑Barré syndrome), prior lymphomas or certain other cancers, COPD, or significant liver disease.
• Alcohol does not have a direct known interaction but heavy use can worsen liver problems; patients with liver disease should limit or avoid alcohol.

Monitoring needs:

• Before and during treatment, clinicians often monitor: TB and hepatitis B status, complete blood counts, liver function tests, and clinical signs of infection, heart failure, neurologic changes, or malignancy.
• In some cases, drug levels and anti‑drug antibodies may be measured to evaluate loss of response or guide dose adjustments, similar to IV infliximab practice.

Q: What is Zymfentra and how is it different from IV infliximab (such as Remicade or Inflectra)?
A: Zymfentra is a subcutaneous formulation of infliximab‑dyyb used for maintenance treatment of moderate to severe Crohn’s disease and ulcerative colitis in adults after IV infliximab induction; it contains the same active antibody as IV infliximab products but is given as a fixed 120‑mg under‑the‑skin injection every 2 weeks at home instead of weight‑based infusions in an infusion center.

Q: How soon might I feel better after starting Zymfentra?
A: Most people experience symptom improvement during or soon after the IV infliximab induction phase (over the first 6–10 weeks), and Zymfentra—begun around Week 10—is intended to maintain that response and keep you in remission over the long term.

Q: Can I give Zymfentra injections to myself?
A: Yes, after training from a healthcare professional and reviewing the Instructions for Use, many patients or caregivers can safely self‑inject Zymfentra using a prefilled pen or syringe in the thighs, abdomen, or (for caregivers) outer upper arms.

Q: What should I do if I miss a dose?
A: If you miss a scheduled injection, take the dose as soon as you remember and then continue with injections every 2 weeks from that new date; do not inject two doses on the same day, and contact your prescriber if you are unsure how to reset your schedule.

Q: Is Zymfentra safe during pregnancy or breastfeeding?
A: Limited data from infliximab use in pregnancy have not shown a clear increase in birth‑defect risk, but the drug can cross the placenta in later pregnancy and remain in the baby’s blood for months, so live vaccines are delayed for at least 6 months after birth; there are no direct data for Zymfentra in breast milk, though IV infliximab appears at low levels, so decisions about treatment and breastfeeding should be made with your gastroenterologist and obstetric or pediatric team.

Q: Do I need special monitoring while on Zymfentra?
A: Your healthcare provider will usually check for tuberculosis and hepatitis B before treatment and may monitor blood counts, liver tests, and symptoms of infection, heart failure, neurologic problems, or cancer regularly while you continue on Zymfentra.

Storage:

• Store Zymfentra prefilled pens or syringes in the refrigerator at 36°F to 46°F (2°C to 8°C); keep them in the original carton to protect from light.
• If needed (for example, when traveling), they may be kept at room temperature 68°F to 77°F (20°C to 25°C) for up to 14 days; once kept at room temperature, do not return them to the refrigerator and discard if not used within 14 days.
• Do not freeze or shake the product, and do not use it if it has been frozen, left in direct sunlight, or appears discolored or contains particles.

Disposal:

• Zymfentra devices are single-use; do not reuse a pen or syringe and do not share it with anyone else.
• After injection, place used pens or syringes (and needles) in a puncture-resistant FDA-cleared sharps container; follow local or pharmacy instructions for disposal and never throw loose sharps into household trash or recycling.
• Discard any product that is expired, has been stored outside the recommended conditions, or has been at room temperature longer than 14 days.