Solve this compounding problem (please?)

[crossurfingers]

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Doctor's rx-
Enalapril 1mg/1mL suspension
Sig: Give 0.13mL po BID
Disp: 30 days supply

A coworker came up with one 10mg enalapril tablet + 5mL Ora-plus + 6mL Ora-sweet as the correct way to fill it. Can someone please explain?

 

[WVUPharm2007]

If it were me, I'd dissolve the pulverized tablet in 7 or 8mLs of solvent, then qs to 10mL...bam 10mg/10mL. The only way 11mL of additive solutions makes any sense is if it's one of those weird solution combinations that lose volume when mixed...which does happen. No idea if the above would constitute such a combination, however.

 

[njac]

we compound enalapril at work - I think the recipe is in the lexi-comp drug info book under extemporaneous preparations.

 

[SELDANE]

Assuming you want to keep the 1mg/ml concentration, your best bet is to make about 30cc's of suspension. Because of adhesion to both the bottle and oral syringe anything less is not so practicle. The previous poster from WVU was correct. However increase my multiple of 3. Thus use 30mg of enalapril (any combination will be fine) use about 5 or 9 ml's of suspending agent and qs with Ora Sweet or syrup of choice. Be sure to let the patient know to keep it in the fridge and discard any product after 30 days.

 

[Old Timer]

Assuming you want to keep the 1mg/ml concentration, your best bet is to make about 30cc's of suspension. Because of adhesion to both the bottle and oral syringe anything less is not so practicle. The previous poster from WVU was correct. However increase my multiple of 3. Thus use 30mg of enalapril (any combination will be fine) use about 5 or 9 ml's of suspending agent and qs with Ora Sweet or syrup of choice. Be sure to let the patient know to keep it in the fridge and discard any product after 30 days.

I must respectfully disagree. Since you will only need 7.8 ml, the remaining 2.3 ml should take care of any adhesion problems. I don't have the protocol in my mind, but I would pre-mix the Ora-Plus and the Ora-Sweet. aa qs to 10ml and use the resultant mixture as the suspending agent. Of course, you don't start out with the entire 10ml, saving some to rinse the last bit of enalapril out of the mortar and into the bottle.

 

[SELDANE]

I must respectfully disagree. Since you will only need 7.8 ml, the remaining 2.3 ml should take care of any adhesion problems. I don't have the protocol in my mind, but I would pre-mix the Ora-Plus and the Ora-Sweet. aa qs to 10ml and use the resultant mixture as the suspending agent. Of course, you don't start out with the entire 10ml, saving some to rinse the last bit of enalapril out of the mortar and into the bottle.

I fail to see how preparing 10 ml of product is practicle for either the patient or the pharmacist that has to do the compound. From both an accuracy perspective (administration and preparation) and a stability factor dispensing 30 ml would make more sense. It's alot eaiser to pulverize and dissolve a tablet or tablets in 30 ml of syrup than it is in 10 ml.

 

[Old Timer]

I fail to see how preparing 10 ml of product is practicle for either the patient or the pharmacist that has to do the compound. From both an accuracy perspective (administration and preparation) and a stability factor dispensing 30 ml would make more sense. It's alot eaiser to pulverize and dissolve a tablet or tablets in 30 ml of syrup than it is in 10 ml.

If you made 30 ml, you would need three tablets or you would loose the concentration of 1mg/ml. So it's still one tablet for each 10mg tablet. Why would you waste the drug and the diluent to make 30ml when you only need 10 ml?

 

[FruitFly]

If you made 30 ml, you would need three tablets or you would loose the concentration of 1mg/ml. So it's still one tablet for each 10mg tablet. Why would you waste the drug and the diluent to make 30ml when you only need 10 ml?

Yep

 

[jpharm445]

If you made 30 ml, you would need three tablets or you would loose the concentration of 1mg/ml. So it's still one tablet for each 10mg tablet. Why would you waste the drug and the diluent to make 30ml when you only need 10 ml?

If it's difficult to work with 10 ml in practice, and if there's significantly more error associated with the smaller volume, I can see why seldane would want to increase the volume. Since I have approximately zero experience, I have to ask if it actually is difficult and impractical to work with 10 ml. Is it? If not, then avoiding waste is obviously the best policy.

 

[Old Timer]

If it's difficult to work with 10 ml in practice, and if there's significantly more error associated with the smaller volume, I can see why seldane would want to increase the volume. Since I have approximately zero experience, I have to ask if it actually is difficult and impractical to work with 10 ml. Is it? If not, then avoiding waste is obviously the best policy.

There is no greater error in measuring 2 x 5 ml or 2 x 15ml. There is no difficulty in working with 10 ml, at least not that I have experienced in 26 years of practice....

 

[FruitFly]

we compound enalapril at work - I think the recipe is in the lexi-comp drug info book under extemporaneous preparations.

so what is this fabled lexi-comp recipe?

And to those who will make 30mLs of product for only 10mLs needed, if one happened to live in a state with a compounding board requirement, they'd get severely penalized for wasting product.

 

[Megas]

The fabled Lexi-Comp protocol may be copyrighted so although I posted it late last night, in hindsight, I deleted it this a.m. I can't post the link cause it's restricted to subscribers. If you'd really really really like the Lexi-Comp enalapril extemporaneous protocol, PM.

 

[Old Timer]

The formula quoted in this article is the one used by Children's Hospital of Philadelphia. I just can't remember if they store at room temperature or in the fridge.

 

[njac]

at work we keep it in the fridge.

 

[Glycerin]

The formula quoted in this article is the one used by Children's Hospital of Philadelphia. I just can't remember if they store at room temperature or in the fridge.

I made that using that same recipe on my community clinical rotation. It was definitely more than 10 mL, though, but the Rx required a lot more.

 

[pharmtech218]

I'm really trying to grasp out to do this type of calculation, and its really put me in a bind at my current pharmacy. Can anyone help me please??? I'd like to know how its done.
**If you mix 3.3gm of a 3% ointment with 11.7gm of a 10% ointment, what is the final concentration?**
Please help...thanks!

 

[rxlea]

I'm really trying to grasp out to do this type of calculation, and its really put me in a bind at my current pharmacy. Can anyone help me please??? I'd like to know how its done.
**If you mix 3.3gm of a 3% ointment with 11.7gm of a 10% ointment, what is the final concentration?**
Please help...thanks!

Well, think about how many grams you have from each percentage...

 

[gtpederson]

I'm really trying to grasp out to do this type of calculation, and its really put me in a bind at my current pharmacy. Can anyone help me please??? I'd like to know how its done.
**If you mix 3.3gm of a 3% ointment with 11.7gm of a 10% ointment, what is the final concentration?**
Please help...thanks!

3.3g x 3% = X grams
11.7g x 10% = Y grams

(X+Y) / 15g = final conc

 

[Rebel78]

I'd call the MD and get the concentration changed. Giving 0.13 ml orally could be a problem.

 

[txpharmguy]

For billing purposes you'd want to bill for 10 cc, but from a practical standpoint you'd want to probably dispense 20-30 cc. An extra 10 mg enalapril and Ora+ and Ora Sweet would probably cost about 25-30 cents in ingredient costs. Make sure you have a discard after disclaimer on your bottle.

 

[Clavulanic]

If you made 30 ml, you would need three tablets or you would loose the concentration of 1mg/ml. So it's still one tablet for each 10mg tablet. Why would you waste the drug and the diluent to make 30ml when you only need 10 ml?

I agree.
I would think you would use a 10mg tablet of enalapril and then qs to a volume of 10mL with your solvent and sweetener.

Why would you want 11mL like the OP said? And what's with the 0.13mL dosing? I would think that would be quite difficult for the patient to measure. I'm also curious as to what such a small dose is being used for.

 

[DYSF777]

I'm also curious as to what such a small dose is being used for.

Hypertensive cat with chronic renal failure.

 

[pharmtech218]

Thank you sooooo much!!! I appreiate this!

 

[Sparda29]

I agree.
I would think you would use a 10mg tablet of enalapril and then qs to a volume of 10mL with your solvent and sweetener.

Why would you want 11mL like the OP said? And what's with the 0.13mL dosing? I would think that would be quite difficult for the patient to measure. I'm also curious as to what such a small dose is being used for.

Yeah, if I got a prescription for that, I'd call up the prescriber and recommend changing the solution to 1 mg/10 mL. It would be much easier to manufacturer and measure for dosing. This way, you're giving 1.3 mL twice daily and making a total quantity of 78 mL (round it up to 80 or 90, whatevs).

 

[eventualeventer]

With cats, a smaller volume is often easier to get in the cat than a larger volume, the latter being easier for the cat to drool back out unless you give it in multiple small aliquots, giving the cat more time to become pissed off and plan an escape. Also, if you're measuring it in 1 mL syringes for accuracy, using 2 syringes is more of a pain when juggling a feline, but a larger diameter syringe is more unwieldy with a tiny mouth and a cat who wants to spit it all back on the floor. Just my .02 as a vet student and cat owner. I would defer to the pharmacist's judgment if the ability to accurately dose the cat is in question, however.

 

[txpharmguy]

Since, it's for a cat and not subject to third party billing, I'd call the vet to see if I could dispense for 30 ml. I'd probably also flavor it with a little sardine or chicken flavoring (about a 1/2 ml-remove that from the Ora Sweet volume). You should dispense the bottle with an adapt-a-cap or similar device, and provide a 1.0 ml syringe (which has graduations as small as 0.02, I believe---not at work, so can't check for certain). Also, I want to say that enalapril MAY be stable for up to 91 days under refrigeration, but I'll have to double check my source, again at work. I'll update on Monday when I look it up.

 

[txpharmguy]

enalapril 1 mg/ml made with tablets and 50/50 ratio of Ora Plus and Ora Sweet is stable for 91 days under refrigeration
Reference: Pediatric Drug Formulations 5th Edition Ohio, 2004 pg 101
Also, I did look at the 1 ml syringes and they have graduations down to 0.02 ml, so drawing up 0.13 ml could be done fairly accurately