Drug interactions
Clozapine + Epinephrine racemic
Severity: Major
Clozapine and Epinephrine racemic: major interaction.
Last updated Sources: UK SmPC
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
Clozapine blocks alpha-1 adrenergic receptors, so epinephrine's vasoconstrictor effect is blocked while its beta-mediated vasodilation and tachycardia remain. This can cause paradoxical severe hypotension and tachycardia. Racemic epinephrine by inhalation has less systemic exposure, but systemic use carries the greatest risk.
What this interaction means in plain words
Clozapine and Epinephrine racemic 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
Clozapine alpha-1 adrenergic blockade leaves epinephrine's beta-agonist effects unopposed (epinephrine reversal).
What to do
For hypotension in clozapine-treated patients, prefer a pure alpha agonist such as phenylephrine or norepinephrine over epinephrine. Monitor blood pressure and heart rate closely when epinephrine is required, such as in anaphylaxis.
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
- Clozapine Viatris 100 mg Orodispersible Tablets - SmPC sections 4.3/4.5 (names the partner; "reverse the pressor effect of epinephrine") — electronic medicines compendium (UK SmPC)
Other interactions of Clozapine
- Clozapine + Deferiprone Contraindicated
- Clozapine + Irinotecan Contraindicated
- Clozapine + Pimozide Contraindicated
- Clozapine + Thioridazine Contraindicated
- Acalabrutinib + Clozapine Major
- Adagrasib + Clozapine Major
Frequently asked questions
Can I take Clozapine with Epinephrine racemic?
MediHelp rates the interaction as major. Clozapine and Epinephrine racemic 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. Clozapine blocks alpha-1 adrenergic receptors, so epinephrine's vasoconstrictor effect is blocked while its beta-mediated vasodilation and tachycardia remain. This can cause paradoxical severe hypotension and tachycardia. Racemic epinephrine by inhalation has less systemic exposure, but systemic use carries the greatest risk.
How serious is the interaction between Clozapine and Epinephrine racemic?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: For hypotension in clozapine-treated patients, prefer a pure alpha agonist such as phenylephrine or norepinephrine over epinephrine. Monitor blood pressure and heart rate closely when epinephrine is required, such as in anaphylaxis.
What other medicines interact with Clozapine?
MediHelp also lists interactions of Clozapine with, for example, Deferiprone, Irinotecan, Pimozide. The full list is on the Clozapine page.
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