Finding a source for generic substitutions

[tompharm]

I was wondering if other pharmacists can help me find a resource or method of finding generic substitutions that are equivalent. For example Diltiziazem comes in a thousand different time released versions. I want to find a resource where I can type in the drug into the system and find what I can substitute it for. Like diltiazem CD or LA or XT. Where can I find so that I know for sure that they are equivalent. I looked at orange book but I don't see where it shows they are equivalent. I also tried just typing the drug into McKesson ordering system and it really doesn't show equivalents. Please let me know if I am doing something wrong and if you can help me.

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[BidingMyTime]

um, the orange book is the only resource I'm aware of. You will learn more about how to use the orange book in pharmacy school. For most oral drugs, you are looking for things that are AB rated. For instance, Cartia XT is AB rated to Cardizem CD, therefore its considered a generic equivalent. For anything, the first letter has to be A for it to be considered equivalent (the 2nd letter refers to the dosage form, and I think maybe if the drug is a biological? I don't have an orange book in front of me to reference....the dosage form letter would have to match for the 2 products to be equivalent) So like if there was an AT brand of diltizem (there isn't, this is just for discussion), it would not be equivalent to Cardizem CD, because the dosage form is different.

 

[Ackj]

I didn't know there was an actual book anymore. Pretty sure it's just the website now (which, admittedly, is a bit complicated).

 

[Sine Cura]

I never found an easy way. Even Drugs@FDA will say something is BX-rated (but BX-rated compared to what?)

For diltiazem it helps to know what are the O.G. NDAs and find out what you actually have on hand so you remember.

Dilacor XR (AB2) - NDA 020092
Cardizem CD (AB3) - NDA 020062
Tiazac (AB4) - NDA 020401

Then go to the "online Orange Book" (Drugs@FDA), search for these NDA numbers, then click on therapeutic equivalents to find the ANDAs for the generics. Then you find what's on the shelf, go find the DailyMed listing (Google search), and see what the ANDA or NDA is (for authorized generics)

Drugs@FDA: http://www.accessdata.fda.gov/scripts/cder/drugsatfda/

For example, Sun/Caraco has generics for Tiazac (AB4) and Cardizem CD (AB3). Teva diltiazem is generic for Cardizem CD. Mylan diltiazem is generic for Dilacor XR (AB2), and these are the only generics we have, so at least I know in the 0.00001% chance a prescriber actually gives a crap

 

[lapharmacienne]

If you have access to clinical pharmacology, that information is available under the "How supplied" section. Therapeutic equivalent formulations are grouped together

 

[FarmD711]

If you have an iPhone there is a great app called rxorange. Paid 99 cents and definitely worth it

 

[Sine Cura]

Clinical Pharmacology - pharmaceutical equivalents are grouped together but therapeutic equivalents are NOT grouped together

Rxorange - the special topic section for diltiazem is a good start but since NDC codes are not in the Orange Book there is no simple way to know if the product you are ordering is A*-rated to such and such. Also there is no way to tell what's an authorized generic from the Orange Book.

 

[farmadiazepine]

And what really is the clinical difference of giving a patient Tiazac 360mg vs. Diltiazem CD 360mg vs. Dilacor XR 360mg?

 

[trailerpark]

If you have an iPhone there is a great app called rxorange. Paid 99 cents and definitely worth it

By 99 cents do you mean $3.99?

 

[FarmD711]

Ahhhhhh it was .99 when I got it earlier this year haha. Inflation!

 

[trailerpark]

Is rxorange better than iGeneric?

 

[FarmD711]

Not familiar with i generic so I guess I can't say