Infliximab is a chimeric monoclonal antibody (IgG1κ) that binds with high affinity and specificity to both soluble and transmembrane forms of human Tumor Necrosis Factor-alpha (TNF-α), neutralizing its biological activity. It is a potent immunosuppressive biologic agent used to manage severe autoimmune and inflammatory conditions. In the Indian context, it is a critical therapy for patients with moderate-to-severe disease refractory to conventional treatments.
Adult: Rheumatoid Arthritis: 3 mg/kg at 0, 2, and 6 weeks, then every 8 weeks. May increase to 5 mg/kg or adjust interval to 6 weeks if suboptimal response. Crohn's Disease/Ulcerative Colitis: 5 mg/kg at 0, 2, and 6 weeks, then every 8 weeks. Ankylosing Spondylitis/Psoriatic Arthritis/Plaque Psoriasis: 5 mg/kg at 0, 2, and 6 weeks, then every 8 weeks.
Note: For intravenous infusion only. The 100mg lyophilized powder must be reconstituted with 10 mL of Sterile Water for Injection (SWFI) using a 21-gauge or smaller needle. Gently swirl, do not shake. Further dilute in 250 mL of 0.9% Sodium Chloride Injection. Infuse over a period of not less than 2 hours using a low-protein-binding filter. Patient must be monitored for infusion reactions during and for at least 1-2 hours post-infusion.
Infliximab binds to soluble and membrane-bound TNF-α, a pro-inflammatory cytokine central to the pathogenesis of several autoimmune diseases. This binding prevents TNF-α from interacting with its receptors (p55 and p75) on cell surfaces, thereby inhibiting TNF-α-mediated cellular responses, including the release of other inflammatory cytokines (IL-1, IL-6), adhesion molecules, and matrix metalloproteinases. It also lyses cells expressing transmembrane TNF-α through complement-dependent cytotoxicity and antibody-dependent cell-mediated cytotoxicity.
Pregnancy: Pregnancy Category B (US FDA). Limited human data. Use only if clearly needed. Infliximab crosses the placenta in the second and third trimesters; infants may have detectable levels for up to 6 months. Avoid live vaccines in the infant until drug clearance is confirmed.
Driving: Dizziness and visual disturbances may occur as part of infusion reactions. Patients should be cautioned about driving or operating machinery on the day of infusion if they experience such effects.
| Anakinra, Abatacept, Tocilizumab | Concomitant use with other biologic DMARDs or potent immunosuppressants significantly increases risk of serious infections without demonstrated added benefit. | Contraindicated / High |
| Live Vaccines (MMR, Varicella, Yellow Fever, Oral Polio, Rotavirus) | Risk of disseminated infection. Live vaccines should not be given concurrently. | High |
| Methotrexate | Co-administration reduces the formation of anti-infliximab antibodies and may increase infliximab serum concentrations, improving efficacy. | Moderate (Beneficial) |
| Corticosteroids, Azathioprine, 6-Mercaptopurine | Increased risk of opportunistic infections, particularly hepatosplenic T-cell lymphoma (HSTCL) in young patients with Crohn's disease. | Moderate (Caution) |
| Warfarin | Case reports of increased INR and bleeding; monitor INR closely. | Moderate |