Phenobarbital 100 v 97.2

[pharmalt82]

What rules do you follow when substituting one for the other?
The pure 100 isn't available sometimes.

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[WVUPharm2007]

Call (or "call") the physician and tell them you are going to substitute it. They won't care. But you can't do a straight substitution without a prescription or notation saying the MD is fine with the slightly different dose.

 

[pharmalt82]

Call (or "call") the physician and tell them you are going to substitute it. They won't care. But you can't do a straight substitution without a prescription or notation saying the MD is fine with the slightly different dose.

Makes sense. This is why I see pharmacists writing down, even on refills, that they made a "call."

 

[Old Timer]

THEY ARE NOT THE SAME THING.​

Once upon a time, in a galaxy far, far away when pharmacy used the apothecary system Phenobarbital was ALWAYS sold by the grain 1/4 gr, 1/2 gr, 1 gr and 1+1/2 grain.

• 1/4 gr = 15 mg = 16.2 mg
• 1/2 gr = 30 mg = 32.4 mg
• 1 gr = 60 mg = 64.8 mg
• 1+/12 gr = 90mg = 97.2 mg

Depending on how you recon a grain, if it's 60mg/gr you use COL A, if you use 64.8mg/gr you use column B. They are identical and no need to call for anything.

The 100mg tablet is a relatively new strength and cannot be subbed for the 90/97.2 mg tablets.....

 

[zelman]

THEY ARE NOT THE SAME THING.​

Once upon a time, in a galaxy far, far away when pharmacy used the apothecary system Phenobarbital was ALWAYS sold by the grain 1/4 gr, 1/2 gr, 1 gr and 1+1/2 grain.

• 1/4 gr = 15 mg = 16.2 mg
• 1/2 gr = 30 mg = 32.4 mg
• 1 gr = 60 mg = 64.8 mg
• 1+/12 gr = 90mg = 97.2 mg

Depending on how you recon a grain, if it's 60mg/gr you use COL A, if you use 64.8mg/gr you use column B. They are identical and no need to call for anything.

The 100mg tablet is a relatively new strength and cannot be subbed for the 90/97.2 mg tablets.....

If you sell a bottle of "100 mg" tablets as a manufacturer, and they all have 97.5 mg of phenobarbital, the FDA says they're close enough.

 

[PharmDstudent]

Inpatient, we automatically label 60mg and 90mg as "may see 64.8mg" or "may see 97.2mg" whenever those doses are dispensed. However, we don't substitute the latter dose for the 100mg dose, so even though it makes things more cumbersome, I have to agree with Old Timer. 🙁

 

[npage148]

I don't think anyone is arguing they are not the same old timer so the 50pt bold underline proclamation is not required.

I'd call or "call" depending on the customer/MD in question. Different but close enough