Drug interactions
Methyldopa + Thioridazine
Severity: Major
Methyldopa 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
Thioridazine has strong alpha-blocking and sedative activity that can produce marked additive hypotension with methyldopa. Thioridazine also carries a significant risk of QT prolongation, which adds to the concern in patients with cardiovascular disease. The interaction is mainly hemodynamic.
What this interaction means in plain words
Methyldopa 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.
Methyldopa belongs to Cardiovascular; Thioridazine belongs to Central Nervous System.
Why it happens
Additive hypotension from alpha-1 blockade and central sympatholytic effects, with possible dopaminergic antagonism.
What to do
Avoid if possible, preferring an antipsychotic with less alpha-blockade and QT risk. If combined, monitor blood pressure and ECG closely.
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 Methyldopa
- Methyldopa + Tranylcypromine Contraindicated
- Iobenguane i + Methyldopa Major
- Lofexidine + Methyldopa Major
- Methyldopa + Pexidartinib Major
- Methyldopa + Pretomanid Major
- Adrenaline-articaine + Methyldopa Moderate
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 Methyldopa with Thioridazine?
MediHelp rates the interaction as major. Methyldopa 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. Thioridazine has strong alpha-blocking and sedative activity that can produce marked additive hypotension with methyldopa. Thioridazine also carries a significant risk of QT prolongation, which adds to the concern in patients with cardiovascular disease. The interaction is mainly hemodynamic.
How serious is the interaction between Methyldopa 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 if possible, preferring an antipsychotic with less alpha-blockade and QT risk. If combined, monitor blood pressure and ECG closely.
What other medicines interact with Methyldopa?
MediHelp also lists interactions of Methyldopa with, for example, Tranylcypromine, Iobenguane i, Lofexidine. The full list is on the Methyldopa page.
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