October 11, 2004
Some types of blood pressure medicines may help to slow the mental deterioration of Alzheimer's disease, a new study suggests. The drugs, called ACE inhibitors, are one of various drugs commonly prescribed to treat high blood pressure.
Scientists in Japan studied 162 men and women living in long-term care facilities, and the findings were published in the journal Neurology, the scientific journal of the American Academy of Neurology. All were suffering from mild to moderate Alzheimer's disease, and all had high blood pressure. The participants were divided into three groups and given different types of blood pressure drugs.
One group was given ACE inhibitors (either captopril or perindopril) that readily enter the brain. The second group was given other types of ACE inhibitors that do not penetrate the brain. The third group received another class of blood pressure drugs called calcium channel blockers.
The participants' thinking and memory skills were tested at the start of the study, and then again one year later. Although the drugs were equally effective in controlling blood pressure, only those who were given the ACE inhibitors that penetrated the brain showed little or no mental decline. In contrast, those who had received one of the other types of blood pressure drugs showed significant declines in memory and thinking.
"These brain-penetrating ACE inhibitors might have benefits not only for the prevention but also for the treatment of mild to moderate Alzheimer's," says study author Rakahi Ohrui, M.D., of Tohoku University School of Medicine in Sandai, Japan.
Still, cautions Daivd Knopman, M.D., of the Mayo Clinic in Rochester, Minnesota, further study is needed. Although he described these findings as "provocative and exciting, the results must be replicated in carefully controlled, blinded studies." In the current study, for example, patients knew which drug they were getting, which could have biased results. Currently, only people with high blood pressure can take ACE inhibitors (which lower blood pressure). Furthermore, the ACE inhibitors, like other blood pressure drugs, don't agree with all patients.
A Range of ACEs
There are many different types of medications for high blood pressure, which doctors refer to as hypertension. Popular blood pressure drugs include diuretics (water pills), beta blockers, calcium channel blockers, and ACE inhibitors. Each type of drug lowers blood pressure by acting on different cells and molecules within the body. If you have high blood pressure, your doctor can determine which drug or combination of drugs would be best for you.
ACE inhibitors, or angiotensin-converting enzyme inhibitors, work by reducing the formation of an enzyme called angiotensin II, a potent constrictor of blood vessels. Examples of ACE inhibitors include the following, but not all of these can penetrate the brain:
- Lotensin (generic name benazepril)
- Capoten (captopril)
- Vasotec (enalapril)
- Monopril (fosinopril)
- Prinivil, Zestril (lisinopril)
- Univasc (moexipril)
- Aceon (perindopril)
- Accupril (quinapril)
- Altace (ramipril)
- Mavik (trandolapril)
All these ACE inhibitors have effects on blood vessels feeding the heart and other parts of the body. Only the two used in the current study, however, Capoten (captopril) and Aceon (perindopril), enter the brain in significant amounts. These were the two that may have benefits for those with Alzheimer's disease. Scientists are not sure why or how these medicines may be effective in slowing the progression of Alzheimer's, and whether one may be more effective than the other. More research will need to be carried out to determine whether these medications might benefit Alzheimer's disease.
In the meantime, it is vital for all people to be monitored for high blood pressure, and to get regular check-ups and treatment as needed. Doctors have evidence that cholesterol-lowering drugs may also benefit those with Alzheimer's, and agree that what's good for the heart is good for the brain.
T. Ohrui, M.D., N. Tomita, M.D., T. Sato-Nakagawa, M.D., et al: "Effects of brain-penetrating ACE inhibitors on Alzheimer disease progression." Neurology 63: October 2004, pages 1324-1325.
David S. Knopman, M.D.: "Effects of brain-penetrating ACE inhibitors on Alzheimer disease progression: A handful of ACEs?"