Is Januvia an effective drug for diabetes?

DEAR DR. ROACH: Is Januvia an effective drug for diabetes? What are the side effects?

ANSWER: Sitagliptin (Januvia) is an oral medication for diabetes mellitus.

The way it works is complicated: It inhibits a molecule called “DPP-4,” which causes an increase in another molecule called “glucagon-like peptide 1.”

GLP-1 causes decreased secretion of the anti-insulin hormone glucagon, so the net effect of Januvia is to block a hormone that opposes insulin.

It may decrease hunger, and has a modest effect on blood sugar: In most clinical trials, it reduces the A1C level by 0.5 to 1 point. It is unlikely, by itself, to cause abnormally low blood sugars.

Side effects include joint aches, which usually go away on stopping the medication.

Allergic reactions are possible as well.

In clinical trials, there were reports of pancreatitis, so any abdominal pain should be reported to your doctor.

Diabetes has become epidemic in North America. The booklet on it provides insight on its diagnosis and treatment. Readers can order a copy by writing: Dr. Roach, Book No. 402, 628 Virginia Dr., Orlando, Fla., U.S.A. 32803. Enclose a cheque or money order for C$6 with the recipient’s printed name and address. Allow four weeks for delivery.

DEAR DR. ROACH: My son doesn’t like to visit me, as my home is too hot for him. I cannot visit him either, as I practically need a snowsuit in his home from fall through spring.

Even in my own house, I can’t bathe without a portable heater in the bathroom.

I am concerned about low thyroid levels.

ANSWER: Although it’s possible your son is the one who is too warm, it sounds more likely that it’s you who is abnormally sensitive to cold.

Cold intolerance is common in the elderly, especially in those who do not have a lot of body fat. However, you are quite right that it is a common sign of low thyroid levels, and I certainly think you should get yours tested.

However, there are other conditions, both common and less so, that can show up in people with sensitivity to the cold. One is anemia. There are many causes of anemia, and when you see your doctor to get your thyroid checked, he or she probably will test for that as well.

Rare causes, like Addison’s disease (an inability to make cortisone) and disease of the hypothalamus, which regulates body temperature, are much less common.

DEAR DR. ROACH: Can indigestion (possibly due to gas) cause hip pain or sciatica? I always experience these two conditions simultaneously.

I get relief by belching, walking and, when all else fails, milk of magnesia.

I suspect that the gas is exerting pressure on the sciatic nerve and thereby causing the hip pain.

Is there any medical history to support this suspicion? Or is there another explanation? Thank you.

ANSWER: I don’t see a direct connection between intestinal distention and nerve pain in the back or hip.

The sciatic nerve — which is a very large structure, nearly the size of your little finger — travels through the sciatic foramen in the hip bone.

It can be compressed by structures in the hip and back, such as a herniated disc or the piriformis muscle.

The contents of the abdomen are far above the sciatic nerve. People with sciatic nerve pain more typically feel pain radiating down the back of the leg into the foot.

The best I can come up with is that, often, people with abdominal distention change their body position, sometimes bending over to relieve the pressure, and this might cause the sciatic nerve, or a different nerve going to the hip, to be pressed on.

DEAR DR. ROACH: I am a 73-year-old woman. I have had migraine headaches with aura since my late 30s. I haven't suffered migraine pain in years, but I still experience the aura from time to time. The aura has increased in size and intensity in recent years; even without the horrible pain anymore, it is rather disturbing, as it blocks my vision while it expands and then dissipates. It usually begins and disappears inside of 20 minutes. What is happening? It is a bit frightening. I now take Premarin, but I did not when the migraines began.

ANSWER: Acephalgic migraine — which refers to any migraine symptoms without headache — is seen more often in women than in men.

Migraine is thought to be a neurological condition (it was previously thought to be vascular, caused by dilation of blood vessels). The electrical activity of the brain cells produces the aura, and activation of the pain fibers in the fifth cranial nerve causes the pain sensation. If that nerve is not affected, then you can have the other symptoms of a migraine without experiencing pain. It can be confused with a transient ischemic attack, which is why it can be frightening.

Migraines can be triggered in women when estrogen levels drop. That’s why some women get migraines around the time of the period (called catamenial migraine), and some women have worsening of migraine or an increase in frequency around the onset of menopause.

The use of estrogen in women with aura is controversial. Certainly, high-dose estrogen, such as the doses used in some oral contraceptives (birth-control pills), increases stroke risk up to eight times, so high-dose estrogen is not recommended in women with any history of migraine with aura at any time.

Some studies also show an increase in stroke risk even with lower levels of estrogen.

If your doctor is giving you estrogen to reduce headaches (which is not unreasonable in some cases of women with perimenopausal migraine), you may already have discussed this.

Otherwise, taking estrogen (like your Premarin) may have more risks than benefits. I would be sure you have had a comprehensive discussion with your estrogen prescriber about continuing it.

Readers may email questions to ToYourGoodHealth@ med.cornell.edu.