Drug interactions
Dextroamphetamine transdermal + Thioridazine
Severity: Moderate
Dextroamphetamine transdermal and Thioridazine: moderate 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
Thioridazine inhibits CYP2D6, which contributes to amphetamine metabolism, so amphetamine exposure may rise. This increases the risk of adverse effects including serotonin toxicity and cardiovascular stimulation. Thioridazine's QT-prolonging effect is also a concern alongside sympathomimetic stimulation.
What this interaction means in plain words
Dextroamphetamine transdermal and Thioridazine 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.
Why it happens
Thioridazine inhibits CYP2D6-mediated amphetamine metabolism, and there is additive pharmacodynamic cardiovascular and serotonergic effect.
What to do
Start dextroamphetamine at a low dose and titrate slowly while monitoring for agitation, tremor, tachycardia and other signs of serotonin toxicity. Check ECG and heart rate, and stop the amphetamine if toxicity develops.
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?
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Other interactions of Thioridazine
- Abiraterone + Thioridazine Contraindicated
- Adagrasib + Thioridazine Contraindicated
- Amiodarone + Thioridazine Contraindicated
- Amisulpride + Thioridazine Contraindicated
- Amitriptyline + Thioridazine Contraindicated
- Amoxapine + Thioridazine Contraindicated
Frequently asked questions
Can I take Dextroamphetamine transdermal with Thioridazine?
MediHelp rates the interaction as moderate. Dextroamphetamine transdermal and Thioridazine 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. Thioridazine inhibits CYP2D6, which contributes to amphetamine metabolism, so amphetamine exposure may rise. This increases the risk of adverse effects including serotonin toxicity and cardiovascular stimulation. Thioridazine's QT-prolonging effect is also a concern alongside sympathomimetic stimulation.
How serious is the interaction between Dextroamphetamine transdermal and Thioridazine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Start dextroamphetamine at a low dose and titrate slowly while monitoring for agitation, tremor, tachycardia and other signs of serotonin toxicity. Check ECG and heart rate, and stop the amphetamine if toxicity develops.
What other medicines interact with Thioridazine?
MediHelp also lists interactions of Thioridazine with, for example, Abiraterone, Adagrasib, Amiodarone. The full list is on the Thioridazine page.
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