Not All Angiotensin Receptor Blockers Linked to Cancer
A new study published in Lancet Oncology has pointed out a link between the use of certain angiotensin receptor blockers (ARBs) and cancer, but healthcare consumers should be aware that not all angiotensin receptor blockers are being associated with an increased risk of cancer.
Currently in the United States, there are seven angiotensin receptor blockers approved by the Food and Drug Administration (FDA) for treatment of high blood pressure: candesartan (Atacand), eprosartan (Teveten), irbesartan (Avapro), losartan (Cozaar), olmesartan (Benicar), telmisartan (Micardis), and valsartan (Diovan). Doctors also prescribe these drugs to treat heart failure, kidney failure in diabetes, chronic kidney diseases, and scleroderma (hardening and thickening of the skin).
Angiotensin receptor blockers work by blocking the action of angiotenin II, a substance that occurs naturally in the body. This substances affects blood pressure in several ways: it causes the blood vessels to narrow, which triggers a rise in blood pressure; and it triggers the release of a hormone that elevates sodium and water levels in the body, which also can make blood pressure rise.
Angiotensin II receptor blockers block the actions of angiotensin II, which relaxes the blood vessels and in turn lowers blood pressure and makes it easier for the heart to pump and circulate blood.
The findings of the new study were the first time an association has been made between the use of angiotensin receptor blockers and a risk of cancer. In the CHARM study (Lancet 2003), which evaluated the ARB candesartan, researchers found that the drug reduced both cardiovascular mortality and hospital admissions for congestive heart failure. The researchers also found an overall increase in fatal cancer that was determined to be by chance.
The ARBs used in the new study included only three: telmisartan (Micardis), which was used by about 85 percent of the patients evaluated; losartan and candesartan. The other four ARBs—eprosartan, irbesarton, olmesarten, and valsartan—were not part of the study. It is not known whether any of these four are associated with a higher risk of cancer.
Thus far, use of ARBs have not been associated with much controversy. Few people experience significant side effects, which can include headache, dizziness, lightheadedness, nasal congestion, diarrhea, and back and leg pain. Rarely use of the drugs can cause kidney failure, liver failure, a decline in white blood cell count, and localized swelling of tissues (angioedema). Because angiotensin receptor blockers can cause birth defects, they should not be used by women who plan to get pregnant or those who are pregnant.
Although results of the new study can serve as an alert to healthcare consumers who take an angiotensin receptor blocker, so far the only possible link to cancer has been with three of the drugs, and especially telmisartan. Not all angiotensin receptor blockers are linked to cancer, but if you have any concerns, you should consult your physician.
Moller BH. Lancet 2003 Nov 15; 362(9396): 1677-78
Sipahi I et al. Lancet Oncology 2010; DOI:10.1016/S1470-2045(10)70106-6.