A team of researchers analyzed the potential side effects of a common blood pressure drug and found that it may increase the risk of a potentially severe bowel condition.
High blood pressure increases the risk of heart attack, stroke, chronic heart failure, and kidney disease. According to some estimates, in 2015, more than 1 billion people were living with high blood pressure worldwide.
Using national, subnational, or community population-based studies to analyze the worldwide trends in blood pressure from 1975 to 2015, researchers found that the number of people with high blood pressure has almost doubled over the past 40 years.
Treatments for high blood pressure include lifestyle changes and medications. The types of drug that doctors prescribe depend on blood pressure measurements and other medical problems that the person might have.
The most common medications include inhibitors, which help relax blood vessels, and channel blockers, which prevent the action of a natural chemical that narrows blood vessels, thus slowing the heartbeat and reducing the amount of blood that needs pumping.
Analyzing the effects of blood pressure drugs
Now, scientists from Imperial College London, United Kingdom, have collaborated with researchers from Ludwig Maximilian University in Munich, Germany, to investigate the efficacy and potential side effects of three common blood pressure medications: ACE-inhibitors, beta-blockers, and calcium channel blockers.
The results of the study appear in the journal Circulation.
To conduct the study, the researchers used genetic analysis. They identified the proteins that these blood pressure drugs target and analyzed data from approximately 750,000 people to identify the genetic variants that code for these proteins.
Then, using data from the U.K. Biobank study, the researchers looked at potential links between these genetic variants and the risk of various diseases. In other words, they used the genetic variants as "[g]enetic proxies for the effect of antihypertensive drugs."
By looking at the gene variations that mimic the effects of these high blood pressure drugs, they estimated the drugs' effects on heart disease risk, stroke risk, and the risk of about 900 different diseases.
"The study of genetic variants that mimic the effect of drugs is evolving as a powerful concept to help prioritize clinical trials and design clinical trials more likely to be successful," explains Dipender Gill, co-lead author of the research.
Calcium channel blockers and diverticulitis
The team found an association between these genetic variants and a lower risk of cardiovascular disease, but their findings also showed that some of the components in these drugs might have adverse effects on gut health.
The results showed that the genes relating to a specific type of calcium channel blocker — called the "nondihydropyridine class" — may increase the risk of a bowel condition called diverticulosis.
Diverticulosis is a condition in which small pouches develop in the lining of the digestive system. These bulges usually appear in the lower part of the large intestine, and they rarely cause issues unless they become inflamed or infected, which is called diverticulitis.
Diverticulosis can lead to a medical emergency if the pouches burst.
Gill says that this is the first time that these specific calcium channel blockers showed a possible connection with diverticulosis.
"We're not sure of the underlying mechanism — although it may relate to effects on the function of intestine muscles, which perform contractions to transport food through the gut."
The researcher adds that further investigation is necessary to confirm the link between blood pressure drugs and bowel disease and that these findings should not influence people who are taking these drugs.
He believes that scientists should use the results of the study as guidance for future research but that doctors should not change their prescribing guidelines for now.