substitution with a different dose

[xiphoid2010]

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Just want to get a feel what are other institutions doing out there for these: At my residency site, we made substitutions for non-formulary drug with a formulary drug that had a close but different strength.

E.g: orders for Reclast (5mg), we give the patient Zometa (4mg). Revatio, 20 mg, patient gets half of a 50mg Viagra. Asked my preceptors, the answer: the dose difference is small enough to not impact outcomes while saving a ton of $$$.

Didn't see that during my internships, so it might be a VA thing. Does anyone else do that at their institutions? 😕

 

[spacecowgirl]

The sildenafil I can see, not sure I agree with the zoledronic acid sub. I usually consider 10% +/- the cutoff for rounding doses.

ETA: guess the sildenafil wouldn't qualify either

 

[Praziquantel86]

You can't select a non-formulary drug in our system, so no need for therapeutic interchange. Any non-formulary medications have to go through a formal request process.

My former institution had all therapeutic interchanges done through P&T with a similar system to what you're describing.

 

[owlegrad]

You can't select a non-formulary drug in our system, so no need for therapeutic interchange. Any non-formulary medications have to go through a formal request process.

My former institution had all therapeutic interchanges done through P&T with a similar system to what you're describing.

Our process is similar to what you describe. All formulary substitutions go through P&T.

The question confuses me somewhat though. Aren't all substitutions going to have a different dose? What does that matter? It wouldn't make sense to use the same dose of a different medication if their potencies are different. Maybe I don't understand what we are discussion.

 

[spacecowgirl]

Our process is similar to what you describe. All formulary substitutions go through P&T.

The question confuses me somewhat though. Aren't all substitutions going to have a different dose? What does that matter? It wouldn't make sense to use the same dose of a different medication if their potencies are different. Maybe I don't understand what we are discussion.

Well they are the same drug but for different FDA approved indications and doses. Can't think of too many others that would fall into this...Prolia and its sibling whose name escapes me at the moment.

 

[owlegrad]

Well they are the same drug but for different FDA approved indications and doses. Can't think of too many others that would fall into this...Prolia and its sibling whose name escapes me at the moment.

Thanks!

 

[xiphoid2010]

Well they are the same drug but for different FDA approved indications and doses. Can't think of too many others that would fall into this...Prolia and its sibling whose name escapes me at the moment.

xgeva. And our heme onc pharmacist shot the drug sales rep down.

Glad to hear that private sector institutions are doing the same. These drugs are quite expensive, there's a lot of savings to be had by not falls for the drug company's marketing trick.

 

[doublehh03]

Just want to get a feel what are other institutions doing out there for these: At my residency site, we made substitutions for non-formulary drug with a formulary drug that had a close but different strength.

E.g: orders for Reclast (5mg), we give the patient Zometa (4mg). Revatio, 20 mg, patient gets half of a 50mg Viagra. Asked my preceptors, the answer: the dose difference is small enough to not impact outcomes while saving a ton of $$$.

Didn't see that during my internships, so it might be a VA thing. Does anyone else do that at their institutions? 😕

It happens all the time when I had my hospital rotations. But most institutions have guidelines on dosage for therapeutic substitutions as equivalence is key.

 

[xiphoid2010]

It happens all the time when I had my hospital rotations. But most institutions have guidelines on dosage for therapeutic substitutions as equivalence is key.

my main concern here is the dosage difference is 20-25%.

What a learned in school for compounding drugs is that +/- 5% is considered equivalent.

FDA's definition of bioequivalence is 90% CI of AUC and Cmax falls within 80-125% of the reference drug.

In both cases, being off by 20% and not even factoring the CI, neither of the substitution can be considered equivalent. So then it's a question of whether there is data on if the difference make any clinical difference.