Nicky asked
I take 600 mg of the time-release capsules phenytoin every day to prevent grand mal seizures. They were in my mailbox yesterday for several hours and the temperature outside was 93-degrees. Are they safe to take? The VA sends them to me all the time.
At a glance
- I cannot say with 100% certainty that the drug is still safe to take and has not broken down.
- It’s probably still OK to take. Drugs are manufactured to withstand less than ideal conditions.
Answer
Hi Nicky and thank you for the great question. I checked every pharmacy reference book on my shelf and scoured every digital reference that I have access to. Unfortunately, I will not be able to give you a 100% correct answer, but I can give you my best-educated opinion on the matter.
Your Phenytoin will most likely be fine to use if it is exposed to higher than the manufactures recommended temperatures for just a few hours.
The professional monograph from the manufacturer states “Store at 20 to 25°C (68 to 77°F) [See USP Controlled Room Temperature]. Preserve in tight, light-resistant containers. Protect from moisture.
Fortunately, even though it’s not explicitly stated, drugs are manufactured to be able to withstand less than ideal conditions. Phenytoin is commonly prescribed around the world, in countries that are in warmer climates and don’t have the luxury of air conditioning in the home to cool their drugs (or the folks living there). During the summer, there’s a decent chance that the truck that carried the drugs to the pharmacy before they filled it for you was a bit warm as well.
We know that some drugs are fragile and very sensitive to temperature, but they are usually drugs that need to be kept in the refrigerator or freezer. These medications are sent to your pharmacy in insulated totes with ice packs and are typically insulins, protein-based drugs, and vaccines. I was not able to find any information on phenytoin breaking down at higher than normal temperatures.
If the capsules appear warped, or the gelatin (the actual shell of the capsule) melted and fused with other capsules, then I would call your pharmacy and ask if they can be replaced. If they look fine, then they probably are fine but again, unfortunately, I cannot guarantee this with 100% certainty due to the lack of published data on the matter.
If your phenytoin levels have fallen at your next physicians' visit or you begin to see an increase in seizure activity, it would be a good idea to replace the capsules.
