What Are Anticholinergic Side Effects?

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Certain medications, used to treat several different health and mental health conditions, cause specific side effects due to their anticholinergic effect within the body. Here we will take a look at both the upside and downside of anticholinergic side effects.

What Are Anticholinergic Effects?

Anticholinergic effects are changes that occur within the body when you take in a  substance that prevents acetylcholine from acting as a neurotransmitter, which leads to decreased parasympathetic activity in the body - which can add up to a lot of different symptoms.

 The neurotransmitter acetylcholine is involved in many major bodily functions, in particular muscle functioning, but it also plays an important role in how the brain functions and to a lesser extent how the heart functions. Therefore substances that act in an anticholinergic manner will result in effects that are experienced throughout the body. These substances include certain medications, plant toxins and pesticides. 

Anticholinergic Side Effects

Due to their effect on acetylcholine, medications that aim to target specific symptoms of an illness or disorder often end up causing other unwanted side effects. Some of the time these effects are only temporary and diminish as a person adjusts to the medication. At other times, these side effects can be quite severe and debilitating. Elderly individuals appear to be at higher risk for more significant impairment from anticholinergic side effects and there is some emerging evidence that cumulative effects of anticholinergic medications may raise a person's risk for dementia.

Common Anticholinergic Side Effects

The following are some of the more common side effects that a person may experience when taking a medication that has anticholinergic effects:

  • Blurred vision
  • Constipation
  • Decreased sweating
  • Dizziness
  • Dry mouth
  • Difficulty urinating and/or kidney failure

Other less common side effects include:

  • Bowel obstruction
  • Cognitive impairment
  • Dilated pupils
  • Increased heart rate

Severe side effects can occur in rare cases. If you are experiencing any side effects that are alarming to you, seek medical attention immediately.

What Medications Are Most Likely to Cause Anticholinergic Side Effects?

Anticholinergic side effects are most often experienced by people who are taking certain antispasmodic medicationstricyclic antidepressants, and antipsychotic medications.Other medications that may have anticholinergic effects include medications for Parkinson's disease, some antihistamines and some heart medications. Here are some of the more commonly used medications that have anticholinergic effects.

Antidepressants with Anticholinergic Effects:

The following medications are examples of antidepressants that are known to have anticholinergic effects:

Antispasmodics with Anticholinergic Effects:

The following  are examples of antispasmodic medications that are known to have anticholinergic effects:

Antipsychotic Medications with Anticholinergic Effects:

The following are examples of antipsychotic medications that are known to have anticholinergic side effects:

Medications Chosen for their Anticholinergic Effects

In some cases, medications are specifically prescribed to take advantage of their anticholinergic effects. An example of this would be the use of antidepressants and antispasmodics in the treatment of irritable bowel syndrome (IBS), particularly in cases where the predominant symptom is diarrhea. The anticholinergic effect of certain antidepressants or antispasmodic medications of slowing down the movement of the digestive system is desirable in order to reduce the frequency of diarrhea episodes.

What to Do About Anticholinergic Side Effects

If you are experiencing side effects from your medication, speak with your doctor. They can assess the degree of severity of your symptoms and make a decision as to whether to decrease your dosage or take you off the medication altogether. (Do not discontinue any medication without first speaking with your physician.) Another option for your physician is to switch out any of your other medications that might have anticholinergic effects so as to minimize any compounding effect.

If your side effect symptoms are mild, you may be able to minimize your discomfort by drinking plenty of water. To reduce the likelihood of constipation, be sure that you are eating foods that are high in dietary fiber.

Sources:

Lieberman, J. "Managing Anticholinergic Side Effects" The Primary Care Companion to the Journal of Clinical Psychiatry 2004 6:20-23.

Grey S, Hanlon J. "Anticholinergic medication use and dementia: latest evidence and clinical implications" Therapeutic Advances in Drug Safety 2016 7: 217–224.

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