Thursday, 15 February 2018

Drugs doing more than one thing, it's not always good

Morrow SA, Rosehart H, Sener A, Welk B. Anti-cholinergic medications for bladder dysfunction worsen cognition in persons with multiple sclerosis. J Neurol Sci. 2018 385:39-44.

Bladder dysfunction is common in persons with MS (PwMS), often due to muscle overactivity. Anti-cholinergic medications are considered the first line treatment for bladder dysfunction and are known to worsen cognition in healthy older adults and in persons with dementia. Yet, it is not known if these medications have the same effect on PwMS. Thus, the Objective of this prospective matched-cohort study was to determine if anti-cholinergic medications affect objective measures of cognition in PwMS. 

We recruited PwMS starting either oxybutynin or tolterodine (cases). Cases and controls were tested with the Brief International Cognitive Assessment for MS (BiCAMS) battery prior to starting anti-cholinergic medications and 12weeks later.
  The primary outcome was change on the Symbol Digit Modalities Test (SDMT) between groups; secondary outcomes were changes on the other BiCAMS measures. Analysis to assess the significance of between group differences was performed at 12weeks. Forty eight PwMS starting anti-cholinergic medications and 21 matched PwMS controls were recruited. There was a significant difference (p<0.001) in the change on the cognitive measures over 12 weeks between groups. The controls demonstrated improvement, consistent with practice effect, while the cases remained unchanged. This study demonstrates that anticholinergic medications may have a negative effect on cognition in PwMS.


Anti-cholinergic drugs block acetyl (ace-eee-tile) choline activity. Aceyl choline is a neuro-transmitter. Acetylcholine functions in both the central nervous system (CNS) and the peripheral nervous system (PNS). In the CNS, cholinergic projections from the basal forebrain to the cerebral cortex and hippocampus support the cognitive functions of those target areas. In the PNS, acetylcholine activates muscles and is a major neurotransmitter in the autonomic nervous system.The autonomic nervous system is a control system that acts largely unconsciously and regulates bodily functions such as the heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousalThere are two main classes of acetylcholine receptor, nicotinic and muscarinic. Block acetylcholine and you can get dry mouth constipation  flush skin.


You can get leakage from a bladder because the muscle is contracting too much, anti-cholingrerics can block this. If you can't go, cholinergic agonists can contract the bladder to empty it.  However in addition to blocking over active bladder, it can block nerve action involved in thought processes. 


Why is this important? Because it shows you that the body can use the same system to control more than one function. They could be have universal good things but they can be opposing one good and one bad. Many of the the agents that promote remyelination have alternative functions and don't be surprised is some of those found to be useful in myelination may have unwanted effects. But do we need to take remyelinating drugs forever or just for a short time so that myelination starts?


2 comments:

  1. MD Anti- C drugs seem to me to be prolific - as in even over the counter. I was fond of a daily Anti allergy tablet until learning that they're Anti- C and becoming concerned about the potential impact on my already damaged brain!

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  2. Another reason why clemastine for remyelination is a bad idea as it is highly anticholinergic. They should have trialled oral miconazole instead (an excellent remyelinator without the side effects)

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