Lost The Cap To Descovy Bottle And Tablets Have Been Exposed To Air
In our latest question and answer, the pharmacist discusses the stability of Descovy tablets that have been left in the bottle without the cap.
I seem to have lost my cap to my Descovy medication container, so the medication has been exposed to air, but I have kept the container in a dark and dry place. I still have been taking the medication as prescribed but now I'm wondering if the medication has lost potency because it's been exposed to air. Should I be concerned that the drug has not been working? Should I finish the medication, or just get a new refill?
Dec 11, 2022- Descovy tablets stored in a cool, dry, dark place below 77°F and 60% humidity will remain stable for at least 28 days even without the original cap.
- If you've lost the cap, try to get a replacement from your pharmacy or a prior bottle, or transfer the tablets to another prescription vial while keeping the desiccant packet with them.
- If your tablets show visible signs of degradation, contact your pharmacy for a replacement prescription to ensure the medication remains effective.
Answer
Thanks so much for your question! While it's difficult to give an exact answer as to whether or not your Descovy tablets have been negatively affected by keeping them in an open bottle, I can certainly give you some information about the subject.
Descovy is recommended to be stored in the original bottle with the desiccant, and to be kept tightly closed to protect the tablets from moisture. If you've lost the cap to the bottle, the tablets certainly are more susceptible to being exposed to moisture from the air.
I will say that in all likelihood, the tablets will not have been negatively affected if they have been stored in the conditions you mention in your question (a dark, dry place at a recommended temperature). Descovy tablets don't lose potency simply by being exposed to air, it's certain conditions that can cause problems, like too high a temperature or humidity.
Additionally, data suggests that the integrity of the physical Descovy tablets will be affected by improper storage conditions before the actual drug would degrade or lose any sort of potency.
Descovy Stability Studies
Gilead, the manufacturer of Descovy, released some very helpful information regarding the stability of Descovy tablets in a variety of storage conditions (such as in the original sealed bottle, the original bottle without a seal, and an open petri dish).
I've included a picture of their data in the table below, but on the whole, it appears that if you have stored your Descovy tablets in a cool, dry, and dark place (lower than 77°F and 60% relative humidity), even if not in the original bottle, the tablets will be stable for at least 28 days.
In the table, Descovy is referred to by the abbreviations of the drugs contained in the product (FTC [Emtricitabine]; TAF [tenofovir alafenamide]).

The row that is fourth from the bottom seems to be the most applicable to your situation, and that is the data showing tablet stability for 28 days in an open petri dish at 77°F and 60% humidity.
The last two rows I didn't feel were applicable to you since those are for tablets in the original bottle with a cap, but the induction seal (the paper seal that covers the opening of the bottle) was removed.
The complete document from Gilead can be found below.
What To Do If You Lose The Descovy Bottle Cap
Descovy tablets are recommended to be kept in the original bottle, tightly sealed, to reduce exposure to the environment, specifically humidity.
If you've lost the cap, I recommend trying to find a replacement cap if you can. Likely places would be from a prior bottle of Descovy you have or from your pharmacy.
Alternatively, you could move the tablets to another prescription vial/bottle, and store them that way. If you do this, be sure to keep the desiccant with the tablets.
If you cannot find a suitable replacement capsule or bottle, like the table I've included above shows, just be sure to store your Descovy tablets properly:
- At 77°F (excursions permitted to 15°C to 30°C (59°F to 86°F)
- At or below 60% relative humidity
- Out of direct light
According to the data provided directly from the manufacturer of Descovy, as long as the tablets are stored under these conditions, they are stable for at least 28 days.
Final Words
As mentioned, in regard to exposing Descovy tablets to the environment, we are more concerned with tablet integrity versus the drug being degraded, although drug degradation may certainly happen over a longer period of time.
If you have noticed that your tablets appear to be degraded, I do highly recommend getting a new prescription from your pharmacy since, at that point, they may not be as effective. It's better to be safe than sorry!
Thanks for contacting us and please do so again anytime.
References & sources
- Descovy Prescribing Information — AccessFDA
- Descovy® (FTC/TAF) Storage and Stability — Descovy.com
Glossary — Terms in This Answer
- Desiccant
- A substance that absorbs moisture and is included in medicine bottles to keep tablets dry.
- Potency
- The strength or effectiveness of a medication to work as intended.
- Stability
- The ability of a medication to maintain its quality and effectiveness over time under specific storage conditions.
- Relative humidity
- A measure of how much moisture is in the air compared to the maximum amount the air can hold at that temperature.
- Induction seal
- A protective paper or foil seal that covers the opening of a bottle under the cap to prevent tampering and moisture exposure.
- Emtricitabine
- One of the active antiviral drugs contained in the Descovy medication.
- Tenofovir alafenamide
- The other active antiviral drug contained in the Descovy medication.
- Drug degradation
- The breakdown of a medication's chemical structure over time, which reduces its effectiveness.