In July, I flew from New York City to Phoenix to meet my new book agent. (Trust me, I would not have deliberately sought out 100-degree weather without good reason.) Always thinking ahead, I decided to bring along a fancy new bag specially insulated to keep my insulin cool. Alas, either the bag failed me, or I failed the bag.

After sitting in the airtight trunk of my agent's car during the three-hour drive to Tucson, both the insulated bag and the Lantus emerged hot! This was bad: Insulin is not supposed to get hot. I was due for my daily basal injection of Lantus the next morning, so I needed to find another bottle post-haste.

Embarrassingly enough, I had to ask my new agent to chauffeur me to a drugstore right away. Dear Claire, however, was cheerfully agreeable, and off we went. It was 6:00 on Saturday night by the time we pulled into the drugstore parking lot. When the kind young assistant behind the counter asked for my prescription, I thought that I was home free. I was holding an out-dated prescription that I use for airline boarding, and I figured that my mail order pharmacy would have a prescription on file as well.

Unfortunately, when the assistant called my mail order pharmacy, she was informed that they didn't have a current prescription and couldn't do anything without one. Apparently it wasn't their concern that I was 2,500 miles from home and couldn't reach my doctor for at least twelve hours. Now I began to freak out a little. This was no way to be welcomed to Tucson.

I felt adrift. Have you ever been without your insulin and unable to get more? Trust me, you feel as though you are walking through a parallel universe. Everything looks the same, but nothing feels the same: The ground is spongy, and you know that at any moment you could sink through it. I was going to be in Tucson for four days. I had to get that Lantus.

Still at the pharmacy, I asked the presiding pharmacist, "Can Lantus be warm for a few hours and still work?" He looked at me blankly. I rephrased my question in simpler terms: "Is there a certain number of hours that insulin has to be warm before it's ineffective?" He still wouldn't tell me. Talk about not wanting to take responsibility for anything. He said he couldn't say and, true to his word, he didn't.

So where does that leave you when you need insulin fast? How can it be so hard to get urgent medicine when you're traveling out of state? Are we such a litigious society that all that was on the pharmacist's mind was not getting sued? I was getting the short end of the stick, and I was sickened by it. Soon I would be truly sick.

Leaving the pharmacy, I called my doctor's service and left a message. Early the next morning, however, I had a brainstorm: I called a friend who works as a physician's assistant in North Carolina. I didn't think she could write me a prescription, but maybe she could tell me how long Lantus can be warm and still be effective. When she answered the phone, low and behold, she was working at a pharmacy! "Hold on a minute," she said, "I'll ask the pharmacist." Accommodating caregiver that he was, the pharmacist said that usually Lantus has to be warm for several hours before it goes bad. "If your Lantus isn't cloudy and has no crystals in it," he said, "it should be fine."

I ran to the kitchen, opened the fridge, and inspected my Lantus. Clear as a bell, no crystals - it looked just fine, and I decided to go with it. However, I checked my blood sugar probably eight or nine times that day to reassure myself that the Lantus was really working. It was. I was enormously relieved, and yet extremely disturbed. How could it be so difficult to get a bottle of life-saving insulin?

From this distressing episode, here's what I learned: Carry a current prescription (you'll have to get a new one every six months). Stay on the safe side and don't let your Lantus get hot. The package insert forbids exposing Lantus to temperatures exceeding 86 degrees Fahrenheit and specifically warns (now they tell me) against leaving it in your car on a summer day. If it should get hot and you are in desperate need, start with the "it might be okay if there are no crystals and it's not cloudy" rule, but test frequently to be sure it's working. As for me? Although Arizona is a lovely state with many warm (very) and friendly residents, next summer I'm booking an Alaskan glacier tour.

Editor's note: If you are in dire straits, you can always get NPH and Regular insulin without a prescription to keep you going until your usual prescription comes through.