Drug interactions
Iobenguane i + Nortriptyline
Severity: Major
Iobenguane i and Nortriptyline: major interaction.
Last updated Sources: Health Canada product monograph
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
Nortriptyline blocks the norepinephrine transporter that takes iobenguane into target cells. This reduces uptake and can cause false-negative imaging or reduced therapeutic effect.
What this interaction means in plain words
Iobenguane i and Nortriptyline 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.
Why it happens
Inhibition of the norepinephrine transporter reduces iobenguane uptake.
What to do
If clinically possible, stop nortriptyline for several half-lives before iobenguane use, following labeling. Treat negative imaging with caution if it was not stopped.
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?
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References
Other interactions of Nortriptyline
- Disopyramide + Nortriptyline Contraindicated
- Dofetilide + Nortriptyline Contraindicated
- Dronedarone + Nortriptyline Contraindicated
- Ibutilide + Nortriptyline Contraindicated
- Isocarboxazid + Nortriptyline Contraindicated
- Methylene blue + Nortriptyline Contraindicated
Frequently asked questions
Can I take Iobenguane i with Nortriptyline?
MediHelp rates the interaction as major. Iobenguane i and Nortriptyline 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. Nortriptyline blocks the norepinephrine transporter that takes iobenguane into target cells. This reduces uptake and can cause false-negative imaging or reduced therapeutic effect.
How serious is the interaction between Iobenguane i and Nortriptyline?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: If clinically possible, stop nortriptyline for several half-lives before iobenguane use, following labeling. Treat negative imaging with caution if it was not stopped.
What other medicines interact with Nortriptyline?
MediHelp also lists interactions of Nortriptyline with, for example, Disopyramide, Dofetilide, Dronedarone. The full list is on the Nortriptyline page.
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