Drug interactions
Siltuximab + Theophylline
Severity: Moderate
Siltuximab and Theophylline: moderate interaction.
Last updated Sources: US FDA label
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Siltuximab blocks interleukin-6, which normally suppresses hepatic CYP enzyme expression during inflammation. As IL-6 is neutralized, CYP activity may return to normal and increase theophylline clearance, lowering its levels. This matters because theophylline has a narrow therapeutic index.
What this interaction means in plain words
Siltuximab and Theophylline can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Siltuximab belongs to Miscellaneous; Theophylline belongs to Respiratory.
Why it happens
IL-6 inhibition reverses cytokine-mediated downregulation of CYP1A2 and CYP3A4, increasing theophylline metabolism.
What to do
Monitor theophylline concentrations when siltuximab is started or stopped, and increase the dose if levels drop. The effect may persist for several weeks after siltuximab treatment.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Siltuximab and Theophylline, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 14 days on the web. No card needed.
References
- Sylvant - FDA drug label (DailyMed) — openFDA / DailyMed
Other interactions of Theophylline
- Riociguat + Theophylline Contraindicated
- Adenosine + Theophylline Major
- Apalutamide + Theophylline Major
- Bupropion + Theophylline Major
- Carvedilol + Theophylline Major
- Cimetidine + Theophylline Major
Other interactions of Siltuximab
- Baricitinib + Siltuximab Major
- Atorvastatin + Siltuximab Moderate
- Carbamazepine + Siltuximab Moderate
- Cyclosporin + Siltuximab Moderate
- Ethinyl estradiol-drospirenone + Siltuximab Moderate
- Ethinyl estradiol-levonorgestrel + Siltuximab Moderate
Frequently asked questions
Can I take Siltuximab with Theophylline?
MediHelp rates the interaction as moderate. Siltuximab and Theophylline can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Siltuximab blocks interleukin-6, which normally suppresses hepatic CYP enzyme expression during inflammation. As IL-6 is neutralized, CYP activity may return to normal and increase theophylline clearance, lowering its levels. This matters because theophylline has a narrow therapeutic index.
How serious is the interaction between Siltuximab and Theophylline?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor theophylline concentrations when siltuximab is started or stopped, and increase the dose if levels drop. The effect may persist for several weeks after siltuximab treatment.
What other medicines interact with Theophylline?
MediHelp also lists interactions of Theophylline with, for example, Riociguat, Adenosine, Apalutamide. The full list is on the Theophylline page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
