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Drug interactions

Crizotinib + Cyclobenzaprine

Severity: Major

Crizotinib and Cyclobenzaprine: major interaction.

Last updated

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

Both drugs can prolong the QT interval, so combined use may increase the risk of torsades de pointes, especially with electrolyte disturbances or heart disease. Crizotinib can also cause bradycardia, which further adds to proarrhythmic risk.

What this interaction means in plain words

Crizotinib and Cyclobenzaprine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.

Crizotinib belongs to Oncology; Cyclobenzaprine belongs to Musculoskeletal.

Evidence level: Low

Why it happens

Additive QT prolongation.

What to do

Obtain a baseline ECG and correct potassium and magnesium before combining, then monitor the ECG periodically. Prefer a non-QT-prolonging muscle relaxant if possible.

What to ask your pharmacist

  • Does the benefit of taking both outweigh the risk in my case?
  • Do I need any blood test, ECG or other check while on both?
  • What early warning signs should I watch for, and what should I do if they appear?

Bring a full list of your medicines, including over-the-counter products, supplements and herbal remedies, to every pharmacy visit.

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Frequently asked questions

Can I take Crizotinib with Cyclobenzaprine?

MediHelp rates the interaction as major. Crizotinib and Cyclobenzaprine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Both drugs can prolong the QT interval, so combined use may increase the risk of torsades de pointes, especially with electrolyte disturbances or heart disease. Crizotinib can also cause bradycardia, which further adds to proarrhythmic risk.

How serious is the interaction between Crizotinib and Cyclobenzaprine?

MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Obtain a baseline ECG and correct potassium and magnesium before combining, then monitor the ECG periodically. Prefer a non-QT-prolonging muscle relaxant if possible.

What other medicines interact with Cyclobenzaprine?

MediHelp also lists interactions of Cyclobenzaprine with, for example, Isocarboxazid, Linezolid, Phenelzine. The full list is on the Cyclobenzaprine page.

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