We’ve all done it: left our birth bag in the trunk after we’ve come home from an all-nighter, because food is more important than unloading the trunk right now. But when summer temperatures climb, your car becomes one of the worst places to store medication. Even on a mild day, the inside of a parked car can reach well over 100°F, and on a hot day it can exceed 130°F in under an hour. That kind of heat can damage many common medications, making them less effective — or even unsafe.

Why Heat Matters

Most medications are designed to be stored at room temperature (usually between 68°F and 77°F) with short-term exposure up to 86°F considered acceptable. But in a hot car, temperatures can soar far beyond those limits. Here’s what that can mean for your medications:

• Changes in appearance or smell: Medications that are exposed to high temperatures may melt, separate, discolor, or take on a strange odor — clear signs that they shouldn’t be used.

• Decreased potency: Heat can break down active ingredients in medications, reducing their effectiveness. This can be dangerous if you rely on precise dosing, such as with pitocin, Vitamin K, or RhoGAM.

• Unpredictable effects: Some medications can become unstable or degrade into harmful compounds when exposed to high heat, especially over time.

Medications That Are Especially Heat-Sensitive

As a midwife, you may carry certain medications that are particularly vulnerable to heat damage. These include:

• Oxytocin (Pitocin): Heat can reduce its effectiveness in controlling postpartum hemorrhage.
• Methergine: Should be kept refrigerated; this can be at room temp for up to 14 days total, but exposure to heat above 77°F can render it useless.
• Rh immune globulin (RhoGAM): Must be kept refrigerated; exposure to heat can render it inactive.
• Misoprostol (Cytotec): Though stable in tablet form, extreme heat can cause degradation over time.
• Vitamin K for injection: Sensitive to both heat and light; improper storage may compromise potency.
• Epinephrine (for anaphylaxis): Degrades rapidly when exposed to heat, potentially making it ineffective in an emergency.
• Lidocaine (especially with epinephrine): High temperatures can alter stability and reduce effectiveness for local anesthesia.
• Antibiotics for GBS prophylaxis (e.g., penicillin, ampicillin): Even in dry powder form, this should be stored below 86°F. In solution form, just one day in a hot car will kill it.
• Vaccines (any): Should be kept between 36°F and 46°F (2°C–8°C); even brief exposure to high heat can make them ineffective (or even harmful).

If you’re carrying these or similar medications in your birth kit, it’s critical to store them in a temperature-controlled container and to rotate them regularly to ensure efficacy and safety.

Safe Storage Tips

• Never leave medications in a parked car, even for a few minutes. The interior temperature can spike quickly, especially in direct sunlight.
• Use a cooler or insulated bag when transporting medications, especially if you’re traveling or doing visits in the heat.
• Keep medications with you, not in the trunk or glove box. The interior of your bag, or a climate-controlled purse or backpack is a safer bet.
• Watch for signs of damage. If a medication looks, smells, or feels different than usual, it’s best to not use it.
• Talk to your medication supplier about any special storage needs for your prescriptions, especially if you live in a hot climate or travel often.

Bottom Line

When it comes to storing medication, temperature matters more than most people realize. A few hours in a hot car could turn your life-saving prescription into a useless (or harmful) compound. So this summer, treat your medications like you would your groceries or electronics — don’t leave them to bake in the heat.

We’d love to hear from you!

What strategies do you use to keep your meds safe during summer travel or at births? Do you use a specific cooler or insulated bag for your meds? Share your thoughts, tips, or questions in the comments below.

The information provided through this activity is for educational purposes only. This information is intended to provide general guidelines for risk management and those involved in claim process. It is not intended and should not be construed as legal or medical advice.

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RELATED: Cohen et al. (2007). Room-temperature storage of medications labeled for refrigeration. Am J Health-Sys Pharm, 64(16):1711-1715.