Savva's group studied the medical records of 40,770 patients, ages ≥65, who were diagnosed with dementia, comparing them with 283,933 controls.
So a research team led by George Savva at the University of East Anglia, set out to estimate the association between duration and level of exposure to different classes of anticholinergic drugs and subsequent dementia.
Other antidepressants (mainly selective serotonin reuptake inhibitors) with an ACB score of 1 were linked to dementia, but only close to the time of prescription, which the researchers say is unlikely to represent a direct (causal) link. "And the association with dementia increases with greater exposure to these types of medication".
Using anticholinergic medications over depression promotes higher dementia risks, confirmed by the researchers from the University of East Anglia after analyzing the patients who had always been suffering through Parkinson's disease, depression or bladder conditions and prescribed with heavy dosage of certain anticholinergics.
A "robust" link was found between certain anticholinergic drugs, used to treat a variety of conditions, and future incidence of the neurological disorder.More news: Apple hires former Samsung VP in attempt to jumpstart business in Korea
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Interestingly, anticholinergic drugs, and particularly oxybutyrin, have been consistently associated with short term cognitive decline in randomised controlled studies, so a long term risk of dementia is "plausible", they write. "In the meantime, I strongly advise patients with any concerns to continue taking their medicines until they have consulted their doctor or pharmacist".
However, no increased risk was found for drugs with possible anticholinergic activity (ACB score of 1) - and for anticholinergic gastrointestinal or respiratory drugs (ACB score of 3). Not taking the medications could have serious consequences, he said. "This could be caused by a class specific effect, or by drugs being used for very early symptoms of dementia".
The researchers, who report their findings in the British Medical Journal, investigated GP records for more than 40,000 people over the age of 65 with dementia and almost 300,000 without dementia.
Tricyclic antidepressants such as amitriptyline, which are also prescribed for pain and to help with sleeping, and one of the SSRI class, paroxetine (also known as Seroxat), are implicated by the largest ever study to look at this possible risk. "Specifically, for most highly anticholinergic drugs, non-pharmacological and pharmacological alternatives are available and should be considered", they conclude. Nevertheless, the team claims, the findings are signficant enough to warrant reduced prescribing anticholinergics, where possible "With many medicines having some anticholinergic activity, one key focus should be de-prescribing", states study co-researcher Ian Maidment, Ph.D., senior lecturer in clinical pharmacy at Aston University in the United Kingdom.
The researchers do stress that patients prescribed anticholinergic drugs shouldn't just stop taking their medicines.
"Doctors and patients should therefore be vigilant about using anticholinergic medications".