Drug interactions
Dextroamphetamine + Thioridazine
Severity: Major
Dextroamphetamine and Thioridazine: 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 affect cardiac conduction: thioridazine markedly prolongs the QT interval, while amphetamines raise heart rate and blood pressure and can provoke arrhythmias. Together they may raise the risk of ventricular arrhythmia, including torsades de pointes, particularly in patients with underlying cardiac disease, electrolyte disturbance or other QT-prolonging drugs.
What this interaction means in plain words
Dextroamphetamine and Thioridazine 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.
Dextroamphetamine belongs to Central Nervous System; Thioridazine belongs to Central Nervous System.
Why it happens
Additive pharmacodynamic cardiac effects: thioridazine-related QT prolongation combined with sympathomimetic stimulation by amphetamine.
What to do
Avoid the combination where possible, especially in patients with cardiac risk factors. If used together, obtain a baseline and follow-up ECG and keep potassium and magnesium within normal range.
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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Other interactions of Dextroamphetamine
- Dextroamphetamine + Isocarboxazid Contraindicated
- Dextroamphetamine + Linezolid Contraindicated
- Dextroamphetamine + Methylene blue Contraindicated
- Dextroamphetamine + Phenelzine Contraindicated
- Dextroamphetamine + Rasagiline Contraindicated
- Dextroamphetamine + Safinamide Contraindicated
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 with Thioridazine?
MediHelp rates the interaction as major. Dextroamphetamine and Thioridazine 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 affect cardiac conduction: thioridazine markedly prolongs the QT interval, while amphetamines raise heart rate and blood pressure and can provoke arrhythmias. Together they may raise the risk of ventricular arrhythmia, including torsades de pointes, particularly in patients with underlying cardiac disease, electrolyte disturbance or other QT-prolonging drugs.
How serious is the interaction between Dextroamphetamine and Thioridazine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination where possible, especially in patients with cardiac risk factors. If used together, obtain a baseline and follow-up ECG and keep potassium and magnesium within normal range.
What other medicines interact with Dextroamphetamine?
MediHelp also lists interactions of Dextroamphetamine with, for example, Isocarboxazid, Linezolid, Methylene blue. The full list is on the Dextroamphetamine page.
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