drugs, medicine
In a study published in JAMA Internal Medicine, the damages caused by the so-called anticholinergic medications remained permanent and didn't get repaired even after people stopped using them.Kevin/Flickr

Certain common medicines can increase the risk of Alzheimer's and dementia, a new study says.

The study, published in JAMA Internal Medicine, says that the damages caused by the so-called anticholinergic medications remained permanent and didn't get repaired even after people stopped using them.

Anticholinergic medications, according to Healthline, are a class of drugs used to treat sleep disorders, depression, urinary continence, asthma, gastrointestinal cramps and muscular spasms.

They work by blocking acetylcholine, a neurotransmitter that stimulates cell division.

Shelly Gray and team based their findings on 3,500 seniors enrolled in the Adult Changes in Thought (ACT) study.

Researchers found that these medications, when used for a long time or taken in higher doses, placed the user at higher risk of developing dementia later. 

Of the total, 797 people were diagnosed with dementia in seven years.

People in the study who took daily doses of 10 mg of TCAs (tricyclic antidepressants) doxepin; 4 mg of first-generation antihistamines chlorpheniramine (Chlor-Trimeton) and 5 mg of oxybutynin (Ditropan) for urinary incontinence for more than three years had a higher risk of developing dementia than others.

Researchers warned that use of certain over-the -counter drugs like Benadryl, an antihistamine can pose a similar risk to the user.

"Older adults should be aware that many medications—including some available without a prescription, such as over-the-counter sleep aids—have strong anticholinergic effects," first author of the study Dr Gray from the UW School of Pharmacy, said in a news release.

"If providers need to prescribe a medication with anticholinergic effects because it is the best therapy for their patient, they should use the lowest effective dose, monitor the therapy regularly to ensure it's working, and stop the therapy if it's ineffective," Dr Gray added later.

In September last year, researchers from France and Canada reported a similar risk with the use of benzodiazepines, a drug used to treat insomnia-anxiety and Alzheimer's disease. People who used the drug for 90 days increased their risk of the brain disease by 51 percent.

Researchers from Kaiser Permanente in the US reported in December 2013 that acid-suppressing medicines like proton pump inhibitors and histamine 2 receptor antagonists, increased the risk of B12 deficiency, a factor known to increase the risk of dementia.