DEAR DR. ROACH: I get all of my medicine by mail. Since the manufacturers stress keeping the pills at cool room temperatures, I wonder what the excessive heat does to them. The medicine must cook all day in the mailbox — way over 100 degrees here in Florida. I wonder how much the pills or liquids are deteriorating, and how the effectiveness is influenced. — F.N.

ANSWER: You are right to be concerned. All medicines should be stored in a cool and dark place, as direct sunlight and heat can damage their effectiveness. Hormones, such as oral contraceptive pills, thyroid hormone and insulin, are among the most sensitive. Nitroglycerine is as well. Although some are shipped in packaging with cold packs and insulation, that’s not always the case.

I recommend using a local pharmacy, but many people have prescription plans that require them to use mail order. If that’s the case for you, try to make sure the medicine will be delivered when you are available to receive it. If you have a temperature-sensitive medicine, such as the ones I mention above (ask your pharmacist about others), ask your mail-order pharmacy to send it in special packaging during warm-weather months.

DEAR DR. ROACH: My 59-year-old son has cirrhosis, probably from a blood transfusion he had as a teenager. His gastroenterologist tells him he is two years away from going on the transplant list for a new liver. Do you know if someone with compatible blood could donate a piece of his or her liver? Would that provide him with enough healthy liver? Also, he heard that you live only about five years with a new liver. Is that true? — B.M.

ANSWER: Cirrhosis after a blood transfusion makes me suspect that your son’s liver disease is due to hepatitis C. If that’s the case, his gastroenterologist has had or will have a discussion with him about new treatments for hepatitis C that will hopefully keep him from needing a transplant.

However, if he does need a transplant, it can be done from a family member or even from a nonrelated person. There are risks to the donor, but major complications happen in only 1 to 3 percent of cases. The transplanted lobe of the liver does rapidly regenerate. The results for the recipient are comparable to that of deceased organ donors. Only the transplant surgeons can recommend whether a living donor is possible.

For adults in your son’s age group, the likelihood of surviving five years after liver transplantation is about 70 percent.

The booklet on hepatitis explains the three different kinds. Readers can obtain a copy by writing: Dr. Roach — No. 503, 628 Virginia Dr., Orlando, FL 32803. Enclose a check or money order (no cash) for $4.75 U.S./$6 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

DEAR DR. ROACH: I recently was diagnosed with transient global amnesia. I had never heard of this. My primary care doctor sent me for further testing, which included an MRI and MRA with contrast, and a CT scan. All were normal. Can you elaborate further on this condition? — M.T.M.

ANSWER: Transient global amnesia is a cause of retrograde amnesia (“retrograde” meaning you don’t remember things from the past, usually the past day to a month, but sometimes longer; “anterograde” means memory loss forward from the time of the event). Its cause is unknown, but it occurs more frequently in men and women over 50. Your doctor ordered the appropriate tests to make sure it wasn’t a TIA or stroke. Epilepsy sometimes can look similar to TGA, so sometimes an EEG is obtained.

As scary as it sounds, TGA usually doesn’t happen again and doesn’t predict a higher risk of developing memory troubles, stroke or epilepsy in the future.

Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or request an order form of available health newsletters at 628 Virginia Dr., Orlando, FL 32803. Health newsletters may be ordered from www.rbmamall.com.