How Long Can You Leave Tamiflu Suspension Out Of The Refrigerator?

In our latest question and answer, the pharmacist discusses how long Tamiflu suspension is stable at room temperature and in the refrigerator.

How Long Can You Leave Tamiflu Suspension Out Of The Refrigerator?
Mar 09, 2019

Worried mother asked

My 9 month old was prescribed Tamiflu. This morning was Day 3 and gave him the prescribed amount. I realized I left it out so it's been approximately been 12-13 hours at room temperature. We keep our house at 70°. I gave him a second dose anyway. Should I have not done so? I put it back in the refrigerator and is it ok to continue to give it to him until he finishes it?

At a glance

  • Below is an image that summarizes the recommended storage conditions from the manufacturer of Tamiflu: Answer SummaryThe commercially available Tamiflu suspension is stable for 17 days under refrigeration and 10 days at room temperature. The compounded version of Tamiflu suspension is stable for 5 weeks under refrigeration and 5 days at room temperature.


Open And Closed Illustration Of Refrigerator

Tamiflu is a commonly prescribed antiviral medication, used to both treat and prevent the flu in those who may have been exposed to it. It is available in two dosage forms, capsules, and liquid suspension.

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

tan hand holding stopwatch illustration

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 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).

Per the prescribing information:


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