By Stephen Lau

Saturday DEc 17, 2011(foodconsumer.org) -- Researchers from the University of Buffalo found that the use of antibiotics to treat childhood acute lymphoblastic leukemia and other pediatric cancers was linked to increased risk of heart disease later in life.

The study, led by Javier G. Blanco, PHD and released in the Journal of Clinical Oncology, shows merely an association between using antibiotics at an early age with getting heart disease later in life. It did not establish a causal relation, meaning that it may not be the drugs that increase the risk of heart disease.

Dr. Blanco and colleagues began the study seven years ago.  They recruited 487 volunteers who survived childhood cancers.  Of these volunteers, 170 people were diagnosed with anthracycline-related cardiomyopathy and 317 weren’t.

By comparing DNA genotypes of these two groups, the scientists identified a tiny gene variant related to the risk of cardiotoxicity.

In addition to comparing DNA genotypes, the scientists assessed two enzymes, CBR1 and CBR3, which break down anthracyclines into cardiotoxic alcohol metabolites.  They found that higher levels of CBRs or faster enzymes dictate higher levels of these metabolites and more cardio toxicity.

"Anthracyclines are effective drugs used to treat a variety of pediatric cancers.  They are also used to treat breast cancer and other malignancies in adults," Blanco says.  

"After cancer, survivors can develop cardiac toxicity anywhere from one year to more than 15 years after the initial chemotherapy with anthracyclines. The window separating the effectiveness of these drugs from their toxicity is narrow. The dosage has to be precise to achieve a therapeutic effect without toxicity," he adds.

In spite of the risk, anthracyclines are still the most effective way to treat childhood acute lymphoblastic leukemia.  However, Blanco suggests that parents continue to have their children’s health monitored long after the cancer is cured to identify cardiac problems if they develop.

Anthracyclines are not the only drugs that cause heart disease.

L. Slørdal and O. Spigset from Norwegian University of Science and Technology in Trondheim, Norway published a review in 2006 in the journal Drug Safety saying that many drugs can cause all types of heart problems.

Slørdal and Spigset reported that many drugs are associated with the development or worsening of heart failure, and they may also adversely affect the heart as a pump without resulting in symptoms or signs of heart failure.

Dangerous drugs include "anticancer agents such as anthracyclines, mitoxantrone, cyclophosphamide, fluorouracil, capecitabine and trastuzumab; immunomodulating drugs such as interferon-alpha-2, interleukin-2, infliximab and etanercept; antidiabetic drugs such as rosiglitazone, pioglitazone and troglitazone; antimigraine drugs such as ergotamine and methysergide; appetite suppressants such as fenfulramine, dexfenfluramine and phentermine; tricyclic antidepressants; antipsychotic drugs such as clozapine; antiparkinsonian drugs such as pergolide and cabergoline; glucocorticoids; and antifungal drugs such as itraconazole and amphotericin B."

According to the authors, NSAIDs including selective cyclo-oxygenase (COX)-2 inhibitors are able to cause heart disease, particularly in inidviduals with pre-existing adrenal dysfunction.

However, the authors emphasized that two categories of drugs are particularly of concern: anthracyclines and their derivatives, which can cause cardiomyopathy years after drug therapy and children are particularly at risk because they are more vulnerable.    The second type of drugs that need particular attention are NSAIDS, which can cause renal dysfunction and elevated blood pressure, which can boost risk of heart failure in vulnerable individuals.