Ever since my college semester abroad in Chile, I had wanted to return. I finally had the opportunity in 2019, but one major roadblock came up. After a particularly rough flare left me struggling to walk, I had just made the difficult decision to start taking a biologic to manage my ankylosing spondylitis. I knew that depending on a costly, refrigerated medication was going to add some stress and complication to my life, but I didn’t want it to prevent me from following my passion for travel. After researching my options for obtaining my biologic in Chile, it became clear that my cheapest option was to keep my US-based insurance, fill my prescriptions domestically, and then fly with multiple months’ worth of medication to take abroad. This meant I’d have to keep my medication at 36°F-46°F in a portable cooler door-to-door. Biologics manufacturers typically offer travel kits that keep medications chilled in this range for 5-10 hours, nowhere near the 30 hours of travel time I needed to budget for.
Professionally, I am a mechanical engineer and design life-saving medical devices that must be effective, reliable, and failure-proof. I applied those same expectations to devise a method for confidently traveling abroad with biologics. I’m sharing what I’ve learned to help others make sound decisions when traveling with their medications. Note that the strategies I present only work in places warmer than refrigerator temperatures and require a refrigerator at your final destination. This article is meant to be a guideline for reference only. If you’re planning to travel with biologics, make sure to reach out to your biologic’s manufacturer and your medical care team for a list of specific guidelines and defer to them. One of the common guidelines is to never put your biologics in checked baggage; always keep them with you as a carry-on item.
The challenges of traveling with refrigerated biologics can be broken down into three core concepts: 1) Preventing your cooler from getting too cold 2) Ensuring your cooler will last the entire duration of your travel time and 3) Measuring temperature. I’ll review these concepts and then provide a list of materials that I use.
1) Preventing Your Cooler from Getting Too Cold
The least discussed and hardest part of biologics travel is ensuring that your cooler does not get too cold. Home freezers are often kept close to 0°F. This is far colder than the 36°F minimum for most biologics. If you take a lot of ice straight out of the freezer and put it directly into a cooler, that cooler will get close to 0°F. This is too cold!
To understand how to effectively use ice in a medication cooler, it’s helpful to know a bit of chemistry. Every material has a “melting point” (also called a “freezing point”): the temperature at which a material undergoes a phase change from solid to liquid. Once a material begins to undergo a phase change, its temperature will remain constant until the phase change is complete.
With this in mind, make sure you allow your frozen gel packs to reach their melting points before sealing them in a cooler with your medication, or you might freeze your medication. Confirm that your gel pack material’s melting point is not below 32°F or your cooler will stabilize at a temperature that is too cold. For example, I typically leave a frozen 32 oz gel pack out for an hour when room temperature is 62°F – 72°F and 45 minutes when room temperature is 72°F – 82°F. It will be mostly solid at this point, since a material is just beginning to melt when it initially reaches its melting point. If your gel pack is fully melted, it will not keep your cooler cold enough. Note that gel packs will require more or less time depending on a few factors, including your freezer temperature, room temperature, and the size of your gel packs.
You may notice that the melting point of water, 32°F, is lower than the 36°F minimum refrigeration temperature of biologics. Even so, the manufacturer of Humira, AbbVie, recommends using ice in their formal Travel Considerations documentation. In my own testing, I have not found using materials with a 32°F melting point to be an issue. No cooler is a perfect insulator, so some heat will increase its internal temperature. In addition, you should place foam spacers between your gel packs and your medication to create an air gap. Symmetric spacing of gel packs helps maintain a consistent temperature throughout your cooler. As shown, a common configuration is an equal number of gel packs on the top and bottom of your cooler, with your medication sandwiched in the middle.
2) Ensuring Your Cooler Will Last the Entire Duration of Your Travel Time
Decide how long you need a cooler to stay in your biologic’s temperature range based on the requirements of your own travel itinerary, making sure to account for unexpected delays. Then, consider the following factors, which influence how long a cooler will last.
3) Measuring Temperature
To evaluate your cooler, I recommend using a datalogging thermometer, which records temperature over time. It is important to use a datalogging thermometer in a trial run (without your medication) before you travel to confirm that your cooler materials and conditions are acceptable. For this, I place my datalogging thermometer in the location of the cooler where my medications would normally sit. I also try to keep the following factors consistent: the material and size of my gel packs, how long I leave them out at room temperature to warm up, the temperature of my freezer and room, and how I space everything in my cooler. This trial will also give you an estimate of how long the cooler will stay cool. The more closely you can mimic your environmental conditions during travel, the more accurate your estimate will be.
Finally, when you are actually traveling with biologics, a datalogging thermometer can be used to confirm that your cooler stays within its required temperature range. If your cooler accidentally goes out of range, contact your biologics manufacturer. Sometimes brief excursions outside of the standard 36°F-46°F range are acceptable. Humira’s manufacturer, AbbVie, has published this tool to help patients evaluate extreme conditions: https://www.abbviemedinfo.com/temperature-excursion-tool)
For reference, here are the materials that I use when traveling with my biologics. Using two of these gel packs in this cooler typically lasts me around 40 hours at a room temperature of 62°F – 72°F, and 30 hours at 72°F – 82°F. I often re-use similar materials that my biologics are shipped with, but since companies use different shipping materials, you would have to evaluate your own separately.
When traveling for a few weeks and my biologics do not need to be kept in their original packaging, I opt for this smaller device.
The strategy outlined above gives me the flexibility to be where I need to be without compromising my biologic’s efficacy. I hope what I’ve shared helps you do the same!
Happy travels!
Karen
Karen Ladenheim takes Humira for ankylosing spondylitis, Crohn’s disease, and uveitis. She is a mechanical engineer who works on medical devices, including a wearable defibrillator and a robot-assist surgery system. She holds degrees from Stanford University in Product Design (B.S.) and Mechanical Engineering (M.S.). Connect with Karen at LinkedIn.
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