Drug interactions
Hydrochlorothiazide-losartan + Siponimod
Severity: Minor
Hydrochlorothiazide-losartan and Siponimod: minor 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
Siponimod is cleared mainly by CYP2C9, and losartan is a weak CYP2C9 substrate and inhibitor with limited inhibitory effect. A clinically relevant rise in siponimod exposure is unlikely.
What this interaction means in plain words
Hydrochlorothiazide-losartan and Siponimod have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Hydrochlorothiazide-losartan belongs to Cardiovascular; Siponimod belongs to Central Nervous System.
Why it happens
Possible weak competition at CYP2C9, which is not expected to meaningfully reduce siponimod clearance.
What to do
No dose change is needed; monitor heart rate and lymphocyte counts as routinely recommended for siponimod.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Hydrochlorothiazide-losartan
- Aliskiren + Hydrochlorothiazide-losartan Contraindicated
- Dofetilide + Hydrochlorothiazide-losartan Contraindicated
- Hydrochlorothiazide-losartan + Sparsentan Contraindicated
- Aceclofenac + Hydrochlorothiazide-losartan Major
- Aldesleukin + Hydrochlorothiazide-losartan Major
- Amifostine + Hydrochlorothiazide-losartan Major
Other interactions of Siponimod
- Cladribine + Siponimod Contraindicated
- Fingolimod + Siponimod Contraindicated
- Fluconazole + Siponimod Contraindicated
- Influenza virus vaccine quadrivalent intranasal + Siponimod Contraindicated
- Ponesimod + Siponimod Contraindicated
- Siponimod + Thioridazine Contraindicated
Frequently asked questions
Can I take Hydrochlorothiazide-losartan with Siponimod?
MediHelp rates the interaction as minor. Hydrochlorothiazide-losartan and Siponimod have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Siponimod is cleared mainly by CYP2C9, and losartan is a weak CYP2C9 substrate and inhibitor with limited inhibitory effect. A clinically relevant rise in siponimod exposure is unlikely.
How serious is the interaction between Hydrochlorothiazide-losartan and Siponimod?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No dose change is needed; monitor heart rate and lymphocyte counts as routinely recommended for siponimod.
What other medicines interact with Hydrochlorothiazide-losartan?
MediHelp also lists interactions of Hydrochlorothiazide-losartan with, for example, Aliskiren, Dofetilide, Sparsentan. The full list is on the Hydrochlorothiazide-losartan page.
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