Zantac And Midodrine

[davecom]

I'm taking both and I've read about a reaction between the two that may slow the absorption of midodrine. Has anyone else experienced this? I think I may be having it. I inevitably must take them within two hours of each other.

[SpinnyC]

That's really interesting! Do you have a link for where you read that?

I'm on both and have been feeling like the Midodrine isn't really doing anything anymore. But In the past I've also seemed to build up a tollerance for Midodrine so I thought it was just time to up the dose again.

[davecom]

I think it was just drugs.com interaction checker, but I also saw it in the documentation for midodrine - says cimetidine is an interaction because it affects the something cp 450 enzyme system (got that all wrong cant remember exactly, stupid pots), and I know zantac was designed to avoid the cimetidine (Tagamet) problems in that regard but still does affect them, which is probably where the interaction is coming from.

[davecom]

Here's the drugs.com interaction:

ranitidine ↔ midodrine

Applies to: Zantac (ranitidine), midodrine

Theoretically, the coadministration with midodrine may result in decreased clearance of drugs that are primarily eliminated by active tubular secretion such as metformin, cimetidine, ranitidine, procainamide, flecainide, quinidine, and triamterene. The proposed mechanism is competitive inhibition of renal excretion by desglymidodrine, the active metabolite of midodrine. However, clinical data are lacking and no supportive experimental evidence exists. Patients receiving midodrine in combination with drugs that undergo active tubular secretion should be monitored for excessive effects of one or both drugs.

[SpinnyC]

Thanks for this. What I've read seems to say that one or both may either work too much or not as well because they may not be cleared by the kidneys as they should. But it's only a theoretical possibility at this point because no interactions have ever been reported by physicians or patients. I was prescribed both by two different doctors. When I went on the Ranitidine I was told it was fine with midodrine, but still it'd be interesting to see what a doc would say about that specific interaction information.

[issie]

The P450 clearance is one of the pathways your body detox's or eliminates something. From what you have written above - it appears that it may intensify the reaction in the body and make it more potent because you may not eliminate it as fast as normal. At least, that's how I'm understanding it.

Issie