The National Health Service (NHS) is cautioning patients against discontinuing anticholinergic drugs despite some recent adverse findings.
The drugs in question have a range of applications, from blocking hayfever to improving breathing in some chronic lung conditions. They are also used in treatment of hypertension, congestive heart failure, gastrointestinal and genitourinary problems and in certain psychiatric conditions too.
An example of commonly used anticholinergic drugs is a special group of bronchodilators used in chronic obstructive pulmonary disease, which decrease inflammation and mucous secretion in the lungs. This group of drugs includes ipratropium bromide (brand name Atrovent).
Researchers found that the 4% of people who used drugs with definite anticholinergic effects had a small but significantly greater decline in mental ability compared to people not using these drugs. People using drugs with definite or possible anticholinergic effects had an increased risk of death within the two-year period.
The two-year study of the impact of these medications on 13,000 men and women aged 65 and older is part of the Medical Research Council (UK) Cognitive Function and Ageing Studies (CFAS), a large UK-based longitudinal multi-center study initiative looking at health and cognitive function in older adults. Results of the study of anticholinergics appear June 24, 2011 in an advanced online publication of the Journal of the American Geriatrics Society
Anticholinergics affect the brain by blocking acetylcholine, a nervous system neurotransmitter.
Blocking acetylcholine has an effect on involuntary processes in the body, and typical effects are dry mouth, decreased mucous secretion, increased heart rate, pupil dilation, slowing of bowel movements (causing constipation), and urinary retention. The medicines can also have an effect on brain function, which affects concentration, memory and attention, and causes confusion. Among commonly used anticholinergic drugs is a special group of bronchodilator medicines used in chronic obstructive pulmonary disease (chronic bronchitis) to decrease inflammation and mucous secretion in the lungs. This group of drugs includes ipratropium bromide (brand name Atrovent).
The researchers were inspired to conduct this analysis because a recently published systematic review highlighted a link between cognitive impairment and the anticholingeric strength of medications (how much the medication lowers the activity of nerve cells).
"Our findings make it clear that clinicians need to review the cumulative anticholinergic burden in people presenting with cognitive impairment to determine if the drugs are causing decline in mental status," said co-author Malaz Boustani, M.D., Regenstrief Institute investigator, Indiana University School of Medicine associate professor of medicine, and research scientist with the IU Center for Aging Research.
"Physicians should review with older patients all the over-the-counter and prescription drugs they are taking to determine exposure," said Dr. Boustani a geriatrician who sees patients at Wishard Health Services' Healthy Aging Brain Center in Indianapolis.
However the NHS said on its website, "The study had some important limitations, including not being able to verify whether participants had used the drugs as prescribed and difficulties gauging whether the slight mental decline seen in testing translated into a decline in functioning in everyday life. Also, given that the data were gathered around 20 years ago, the study may not reflect the way drugs are currently prescribed and monitored.
These are important findings, but people should not stop taking any of their prescribed medications and should contact their doctor if they have any concerns about adverse effects.
Although certain news sources focussed on the potential risks of various medications, they did not mention the proven benefits. Many of the drugs in question are of great importance in treating and managing serious health problems. The research does not in itself show that these benefits are outweighed by the risks, and people should not stop taking their medication because of this study. If patients have any concerns, they should speak to their doctor or pharmacist, who can review their medicine usage and advise them accordingly.
The study's strengths include its large, community-representative population size, high level of follow-up and use of a validated score to analyse the strength of anticholinergic properties of the drugs used. However, it does have important limitations, it has been argued.
While it has indicated a possible effect of drugs with anticholinergic properties, it has not identified how they might affect the risk of death or found a causative link between the two factors. In other words, the findings do not necessarily prove that the drugs themselves increased the risk of death. However, the study has identified an area worthy of further research, which should ideally consider more complete records of medication use and feature a more in-depth analysis into cognitive performance and functioning.
The Medicines and Healthcare Regulatory Agency, the UK's drug watchdog, has commented on the study's findings, saying:
"All medicines have side effects - no effective medicine is without risk. Our priority is to ensure that the benefits of medication outweigh the risks. The known side effects of anticholinergic medicines are described in the product information for prescribers and in patient information leaflets. Where it is known that taking a combination of medicines may increase the risk of experiencing side effects, it will be reflected in the product information.
"It is important for people taking anticholinergic medicines not to stop taking them. If they have any questions or concerns then they should contact their doctor in the first instance."