sterility rule

Multi-dose Vials and the 28-day Sterility Rule

Article by Patrick M. Carpenter, MS, PharmD, RPh

Patients on injection therapy for erectile dysfunction, testosterone therapy, and other injectable medicines use multi-dose vials of sterile medicine. A multi-dose vial is a container a patient punctures with a needle multiple times over a period of time. Let’s discuss why it’s important for a patient using a multi-dose vial to follow the 28-day sterility rule.

Safety vs. Efficacy

Pharmaceuticals need to satisfy two main objectives: They need to be safe and they need to be effective. Effectiveness has nothing to do with safety. Saying a product still works does not mean it is still safe. An old car without seatbelts and airbags may be effective for getting you from one place to another, but it is not as safe as a newer car with seatbelts and airbags. Both cars are effective, only one is safe.

What is sterility?

Sterility means lack of contamination from infectious agents including germs. A product is either sterile or it is not. A product that does not contain germs is safe in the context of a discussion about sterility.

Sterility Assurance

Rigorous standards must be met during the production of injectable pharmaceuticals to minimize the likelihood of germs in the product. These standards include a special production room containing carefully filtered, particle-free air, production personnel dressed in sterile suits with no exposed skin, and many other safety precautions. Even with these precautions in place, all products are sterilized before being dispensed to the patient.

At the very end of the production process a sterility test is performed to further demonstrate all of the rigorous processes worked as intended. Though some production steps may seem redundant, they are necessary to ensure the product is sterile and therefore safe to use. A sterile product will not cause infection in a patient.

28-day Challenge Testing

Because sterility and safety are so important, even more tests and rigorous precautions are taken in the production of injectable pharmaceuticals. Preservatives are added and challenge tests are done where test vials are purposely contaminated in the laboratory to test the ability of the preservative to keep the product germ free.

Without getting into the incredibly detailed science describing these tests, it has been accepted that multi-use vials can only be used safely for 28 days after the first puncture. Compounding pharmacies are required to demonstrate through challenge testing that the product maintains sterility and is free of germs for a minimum of 28 days after first puncture.

Germs All Around Us

The air we breathe is filled with particles that carry bacteria, fungus, and viruses. This is often how people get sick. The flu spreads when the virus is transported through moisture particles in the air and breathed in by a person who will end up getting sick. Pneumonia, chickenpox, measles, the common cold, strep throat, sinus infection, and other germs exist in the air around us and can cause infection.

With all of these germs around, how are we ever healthy?

Our bodies have certain defenses that protect us. For one, our vital organs are protected inside our body. Our blood is protected by being inside our body and contained within our circulatory system. Blood is a sterile environment. It is free of germs.

The food we eat is broken down into nutrients that end up in our blood, but first the food passes through our stomachs, an environment containing acid and enzymes that destroy bacteria and helps keep our blood sterile. Our stomachs essentially filter nutrients, so germs are kept out of our blood.
Our lungs filter the germ particles and keep them out of our blood when we breathe. Oxygen is filtered by the lungs, and then moved into the bloodstream, but germs are kept out.

Food goes in your stomach, air goes in your lungs, but nothing goes directly into your blood from the outside world without filtration, unless of course, you are administering medication via injection

People commonly get gastrointestinal illnesses or lung illnesses, but blood illnesses are much more rare. This is a beautiful testament to the function of the human body. It protects its most important parts rigorously. Nothing in ordinary human life bypasses these natural defense mechanisms. Food goes in your stomach, air goes in your lungs, but nothing goes directly into your blood from the outside world without filtration, unless of course, you are administering medication via injection.

Injectable Medicine is Different

With injectable medicine you’re bypassing your stomach, lungs, and skin, and injecting directly into your blood. When injecting into your penis you are injecting into a chamber that floods with blood, and when your erection goes away, that blood returns to the rest of your body through your circulatory system.

This is the reason sterility is so important and why you must be concerned with how long you use a multi-dose vial. When the product leaves the pharmacy it is sterile. This is known because of all of the rigorous standards during production mentioned above. After you receive the product, puncture it, and begin using it, there is a risk of introducing germs into the vial. Germs introduced into the vial can multiply in the vial and end up in your blood the next time you inject. It doesn’t matter how careful you are, we are surrounded by germs, there is no way at home to be absolutely certain you didn’t contaminate the vial – but sterile production standards, and added preservatives help protect you, for at least 28 days.

Remember the goal: keep germs out of your blood.

People often struggle with this concept as it relates to sterile injectable medications. We go about our everyday lives, get sick, get better, and we minimize the importance of keeping our blood free of germs, because our body does the job for us. However, if you are injecting medications, you need to be more aware of sterility and safety.

People will sometimes say, “but I used a vial well past 28 days after first puncture and I didn’t get sick, so why should I care?” Well, those people are taking a risk. Just because you didn’t get sick by risky behavior one time, doesn’t mean you will never get sick if you continue to disregard the rules.
Using an injectable medicine beyond 28 days after first puncture is risky. It is not recommended by the scientific community, and not recommended by the pharmacy that made your medication.

How much risk are you willing to take with your health and safety? My suggestion is to take as little risk as possible.

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By Patrick M. Carpenter, MS, PharmD, RPh

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