Q&A: Siponimod drug interactions

Applying the cautionary principle, I would advise not drinking grapefruit juice when starting siponimod and not to drink it on a regular basis after starting it.

Case study

For 40 years, since the age of about 16, the only symptom I could attribute to caffeine was the occasional withdrawal headache, no high or jitters. I could drink caffeinated coffee late at night, go to bed and sleep.

Before starting Siponimod, I had cardiac perfusion scans because my ECG had a minor abnormality. They used adenosine to excite my heart. I switched to decaf coffee because I had to abstain from caffeine for 24 hours before the scan. I have subsequently switched back to caffeinated coffee.

I started Siponimod on 3rd January. From the 17th to the 23rd of February, I consumed two or three mugs of caffeinated coffee at a friend's house on Tuesday and two regular caffeinated lattes in a coffee shop on Wednesday and Friday. That amount of coffee is normal during college holidays. My blood pressure was 130/100 mmHg, which is usually around 125/80 mmHg, and I developed caffeine jitters. I had not reacted to coffee before; these symptoms only happened after taking siponimod.

I did some research on the Internet, suggesting a link between siponimod and adenosine receptors and, therefore, caffeine.

Do you think Siponimod is the cause of my new caffeine sensitivity? Given that the patient leaflet does not advise on caffeine, are there other potential issues associated with siponimod and caffeine? What about other drug interactions?

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Answers

Q: Do you think Siponimod is the cause of my new caffeine sensitivity? Given that the patient leaflet does not advise on caffeine, are there other potential issues associated with siponimod and caffeine? What about other drug interactions?