The 3-2 Rule and How It Protects You

A Physician's Guide to Drug Compounding FDA Guidance

Did you know that the USP categorizes compounding into three risk categories?

Each risk category requires different facility requirements in order to be compliant with the law. Unfortunately for many doctors, only one of these compounding categories is manageable without built-to-purpose clean rooms, specialized air filters, pressurization and pumps along with other key equipment and highly trained staff. Doctors office are most complaint with Low-Risk Compound Sterile Preparations (CSPs). So what does low-risk actually mean and how is it different from high and medium risk?

Welcome to the 3-2 Rule

There is a simple rule to remember that will help you remain compliant with USP guidelines and removed from potential FDA risk. It is called the 3-2 rule and it refers to the guidelines for low-risk compounding. The 3-2 rule requires that doctors mix no more than 3 medications into any one (IV bag) treatment and that all sterile vessels, like a vial or an IV bag, be entered no more than twice. It is important to note that puncturing an IV bag with a sterile needle is still considered to be ‘entering' it. There are a few more guidelines but the 3-2 rule is the most important. (United States Pharmacopeial Convention, 2008)

The USP also places restrictions on the type of aseptic handling and transferring techniques used. You may not mix several sterile vials into a bigger container for the use of several patients, or one patient over several different occasions of treatment. You may also only use simple, single volume transfer to move sterile fluids. An example of this would be penetrating a sterile stopper with a sterile syringe and then injecting that medicine into an IV bag. You would not be able to pull from two different medicines in the same syringe or anything more complicated than the procedure mentioned. Doing so puts you into a higher risk category in the eyes of the USP and the FDA. Also, after preparing a Low-Risk CSP, the compound must be used within no more than 12 hours in order to be compliant. (United States Pharmacopeial Convention, 2008)

Remember, not adhering to these strict guidelines for the low-risk compounding group means that you are mixing in either the medium or high-risk categories and are responsible for meeting the facility requirements set by the government.

Doesn't a hood keep me compliant?

In the eyes of the USP, a hood simply is not good enough. They have set very clear guidelines for the facilities in which medium and high-risk compounding is to take place. They defined these requirements specifically so that purpose built distributers and pharmacies – not a standard doctor's office – would be able to meet them. The facility requirements are outlined in USP chapter 797, but it's not important to know them unless you are interested in investing upwards of hundreds of thousands of dollars in compliant, high-grade clean rooms to meet USP 797 guidelines. Anything beyond the 3-2 rule and the its limitations will push your practice into the medium-risk compounding category

Vertisis provides Help

You might be thinking to yourself, “3 and 2? That's much too restrictive! my patient's regimen is more complicated than that.” Well, naturally it is. These rules were designed to be restrictive. In our opinion FDA has shown a clear bias to naturopathic and integrative medicine. The FDA has investigated many unsanitary compounding operations that have resulted in the deaths of patients. They have found mold, technicians working without gloves, even toaster ovens used to sterilize tools and instruments! (Food & Drug Administration, 2016) It may be inconvenient, but these are people's lives at stake and the FDA takes that very seriously. The FDA has issued guidance for patient safety. It's up to you to keep your practice safe and in line with the law. (Food & Drug Administration, 2017)

One way to do that is to let Vertisis handle your medicine compounding needs. Vertisis is completely USP 797 compliant with our new, modern pharmacy. We pride ourselves on taking a personal touch with each of our valued physicians and patients. By becoming our partner, we help shield you from not just one but two potential sources of liability. By remaining compliant with state and federal law, we take the burden of regulation off of your practice and help shield you from potential malpractice suits resulting from improperly prepared medication. When you administer medication prepared by us, we retain the potential liability for an adverse event, eliminating that exposure for your practice. To learn more please feel free to contact us and discover why integrative and naturopathic doctors are choosing Vertisis Custom Pharmacy.


  1. [1] Food & Drug Administration. (2016). Insanitary Conditions at Compounding Facilities. Silver Spring, MD, United States: Office of Compliance.
  2. [2] Food & Drug Administration. (2017, March 01). Compounding - FDA Implementation of the Compounding Quality Act. Retrieved from
  3. [3] United States Pharmacopeial Convention. (2008). <797> Pharmaceutical Compounding - Sterile Preparations. In General Chapter <797>.