Answer
Tamiflu is a commonly prescribed antiviral medication, used to both treat andprevent the flu in those who may have been exposed to it. It is available in two dosage forms, capsules, and liquid suspension.
Per the manufacturer, Tamiflu suspension can be stored in the refrigerator or at room temperature, although refrigeration is preferred for a few reasons:
- Refrigeration of Tamiflu increases the palatability of the suspension, making it more likely to be well tolerated by children and infants.
- Refrigeration increases the shelf life of the product once mixed.
In terms of how long the liquid the Tamiflu suspension is stable and safe to give when left out of the refrigerator, it depends on which product you have:
- The commercially available Tamiflu suspension (the product that is made directly by the manufacturer) is stable for 10 days at room temperature (up to 77℉).
- Compounded versions of Tamiflu suspension (made by your pharmacist using Tamiflu capsules during times of shortage) are only stable for 5 days at room temperature (up to 77℉).
Most individuals will have the Tamiflu product direct from the manufacturer, but it is important to know if you have the compounded version instead since the room temperature expiration date is shorter!
I discuss below why there are two different versions of Tamiflu suspension and how to store them safely.
Tamiflu Suspension And Compounded Tamiflu
There is extensive published data on the stability of Tamiflu suspension, both at room temperature and under refrigeration.
It is extremely important to know,which type of Tamiflu suspension you were dispensed as stability varies based on which product you have.
The vast majority of people will have received the commercially available product, which is supplied directly from the manufacturer as a white powder blend in a glass bottle. With this product, your pharmacist will add water to reconstitute it when you pick it up.
There have been numerous times recently, however, where there has been a significant shortage of Tamiflu suspension (2013 was a particularly bad year, which was widely reported).
There was such a shortage in 2013 that the CDC (Centers for Disease Control) provided instructions for pharmacists on how to compound a suspension out of Tamiflu capsules (as they were more often available) when the commercially manufactured Tamiflu oral suspension formulation was not readily available.
Shortages of the liquid Tamiflu suspension happen often enough that, in 2013, the prescribing information for the drug was revised to add specific instructions for pharmacists on how to compound it if necessary.
In the next sections, I discuss how long both the commercially available Tamiflu suspension, and compounded version, are safe at room temperature and in the refrigerator.
Tamiflu Suspension (Manufacturer-Labeled Product) Storage Requirements
If you accidentally left your bottle of Tamiflu (oseltamivir) suspension out of the refrigerator, that is okay! The reconstituted suspension (after the pharmacist adds liquid to the powder), is stable at room temperature (up to 77℉) for 10 days.
Since the length of dosing of Tamiflu is generally between 5 and 10 days, it is safe to simply store it in the refrigerator or leave it out at room temperature for the duration of therapy.
There is no stability data after 10 days, so if the prescribed time you are supposed to be using Tamiflu is over 10 days, it should be refrigerated. When refrigerated, it is good for up to 17 days.
Below is an excerpt from the 'Storage and Handling' section from the prescribing information for Tamiflu that summarizes the storage conditions:
"Store constituted oral suspension under refrigeration for up to 17 days at 2℃ to 8℃ (36℉ to 46℉). Do not freeze. Alternatively, store constituted oral suspension for up to 10 days at 25℃ (77℉); excursions permitted to 15℃ to 30℃ (59℉ to 86℉)"
Compounded Tamiflu Refrigerator Requirements
A Tamiflu suspension can be compounded by your pharmacist from Tamiflu capsules if the commercially available product is undergoing a supply shortage.
There are three different liquid vehicles your pharmacist can use to make the suspension:
- Cherry Syrup (manufactured by Humco)
- Ora‐Sweet SF (sugar‐free) (manufactured by Paddock Laboratories)
- Simple syrup (which is a 1:1 mixture of sugar and water)
Regardless of the liquid vehicle, your pharmacist uses to make the compounded Tamiflu suspension, the prescribing information states that they are only stable at room temperature for 5 days (which is less than the 10 days for the commercially available suspension).
Under refrigeration, compounded Tamiflu is stable for up to 5 weeks.
Per the prescribing information:
Storage of the Emergency Compounded Suspension: Refrigeration: Stable for 5 weeks (35 days) when stored in a refrigerator at 2 to 8 C (36° to 46°F). Room Temperature: Stable for five days (5 days) when stored at room temperature, 25 C (77°F).Note: The storage conditions are based on stability studies of compounded oral suspensions, using the abovementioned vehicles, which were placed in glass and polyethyleneterephthalate (PET) bottles. Stability studieshave not been conducted with other vehicles or bottle types.
Final Words
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