What Do Anticholinergic Drugs Do?

Symptom improvement comes from blocking the neurotransmitter acetylcholine

Medically reviewed by Kathleen Daly, MD

Anticholinergic drugs block the action of a chemical messenger called acetylcholine. It plays a key role in involuntary movements needed for muscle and brain function. It transfers signals between nerves and certain types of muscles and organs for normal brain and body function.

Anticholinergic drugs can improve many types of health problems, such as bladder problems, depression, and Parkinson's disease. However, they can also cause a range of adverse effects, including dry mouth, blurred vision, and memory problems, most often in older adults.

This article includes names of anticholinergic drugs, what they treat, and their side effects. It also explains how these drugs work and who should not take them.

Anticholinergic Drug Examples

More than 600 anticholinergic medications have anticholinergic effects. These substances include over-the-counter (OTC) medications, prescription drugs, and plants.

Some anticholinergic drugs are used for their anticholinergic effect. Other drugs are primarily used for other mechanisms of action but also have anticholinergic effects.

The following is a representation of some anticholinergic drugs. Some medications on this list may be marketed under additional brand names. A healthcare provider or pharmacist can inform you of the use and side effects.

Tricyclic antidepressants:

• Amitriptyline

• Anafranil (clomipramine)

• Norpramin (desipramine)

• Tofranil (imipramine)

Antipsychotics:

• Clozaril (clozapine)

• Geodon (ziprasidone)

• Haldol (haloperidol)

• Loxitane (loxapine)

• Prolixin Decanoate (fluphenazine decanoate)

• Seroquel (quetiapine)
  

• Thorazine (chlorpromazine)
  

• Zyprexa (olanzapine)
  

Antiepileptics:

• Depakote (valproate)

• Tegretol (carbamazepine)

• Trileptal (oxcarbazepine)

Parkinson's disease medications:

• Akineton (biperiden)

• Artane (trihexyphenidyl)

• Cogentin (benztropine)

• Eldepryl (selegiline)

• Mirapex (pramipexole)

• Parlodel (bromocriptine)

• Sinemet (carbidopa-levodopa)

• Symmetrel (amantadine)
  

Antidepressants:

• Desyrel, Desyrel Dividose (trazodone)

• Luvox (fluvoxamine)
  

• Pamelor (nortriptyline)

• Paxil (paroxetine)

• Prozac (fluoxetine)

• Zoloft (sertraline)
  

Benzodiazepines:

• Ativan (lorazepam)

• Klonopin (clonazepam)

• Valium (diazepam),

• Xanax (alprazolam)

Opioids:

• Contin (codeine)

• Conzip (tramadol)

• MSiR (morphine)

• Sublimaze (fentanyl)

Antihistamines:

• Benadryl (diphenhydramine) (OTC)

• Claritin (loratadine) OTC

• Vistaril (hydroxyzine pamoate)

Antispasmodics:

• Imodium (loperamide) (OTC)

Antiulcer:

• Tagamet HB (cimetidine) (OTC)

• Zantac (ranitidine) (OTC)

Bronchodilators:

• Advair Diskus (fluticasone- salmeterol)

Cardiovascular:

• Cardizem (diltiazem)

• Jantoven (warfarin)

• Lanoxin (digoxin)

Corticosteroids:

• Cortaren (dexamethasone)

• Cortisone

• Prednisone

• Solu-Medrol (methylprednisolone)

Diuretics:

• Capoten (captopril)

• Hygroton (chlorthalidone)

• Lasix (furosemide)

Urological:

• Detrol (tolterodine)

• Ditropan (oxybutynin)
  

What Is the Cholinergic System?

Your cholinergic system is a branch of your autonomic nervous system. This system plays a key role in functions that include memory, digestion, heart rate, blood pressure, movement, and emotional processing.

The autonomic nervous system includes the neurotransmitter acetylcholine, cholinergic receptors, choline acetyltransferase enzyme, and acetylcholinesterase enzyme. These molecules regulate your immune response and play a crucial role in maintaining internal equilibrium among your bodily systems.

Conditions Treated With Anticholinergics

Anticholinergic drugs treat a diverse range of medical conditions that include the following:

Psychiatric conditions:

• Bipolar disorder

• Delusional disorder

• Drug-induced acute dystonia

• Endogenous depression

• Obsessive-compulsive disorder (OCD)

• Parkinson's disease

• Psychotic depression

• Schizoaffective disorder

• Schizophrenia

• Secondary Parkinsonism

• Severe anxiety disorder

• Severe insomnia
  

Nonpsychiatric conditions:

• Allergies

• Cardiovascular diseases

• Chronic obstructive pulmonary disease (COPD)

• Gastroesophageal reflux disease (GERD)

• Irritable bowel syndrome (IBS)
  

• Muscle spasms/low back pain

• Neuropathic pain

• Urinary incontinence
  

Symptoms Treated

Anticholinergic drugs decrease or block the actions of acetylcholine. They can be effective in addressing the following symptoms:

• Bradycardia (slower than normal heartbeat)

• Gastric acid production

• Lacrimation (oversecretion of tears)

• Nasal and bronchial secretions

• Nausea and vomiting

• Salivation
  

• Sweating
  

Learn More: What You Need to Know About the Nervous System

Anticholinergic Drug Action and Meaning

Anticholinergic drugs work by blocking the action of acetylcholine, a neurotransmitter. Acetylcholine acts on many parts of your body simultaneously. It enables processes such as a steady heart rate, normal breathing and digestion, and cognitive function (thinking, memory, problem-solving).

Anticholinergic drugs prevent acetylcholine from binding to muscarinic receptors. These receptors function in your peripheral and central nervous systems to handle involuntary muscle movements. This can be desirable in situations in which these systems produce unwanted effects due to disease.

By blocking acetylcholine, anticholinergic drugs can reduce involuntary muscle movements in areas such as your lungs, urinary tract, and gastrointestinal tract. They can also help manage symptoms related to cognitive function.

Anticholinergic Side Effects

Anticholinergic side effects are wide ranging. They can vary by individual and typically include the following mild or moderate effects:

• Blurred vision

• Anhidrosis (lack of sweating)

• Dry mouth

• Constipation

• Fatigue

• Mydriasis (dilated pupils)

• Tachycardia (higher than usual heart rate)

• Urinary hesitancy

• Drowsiness

• Nervousness, excitement

• Poor attention

• Mild amnesia and cognitive impairment

• Restlessness

Severe anticholinergic effects can occur based on the drug load (how much drug is active in the body) and individual vulnerability. Since there are so many anticholinergic drugs, severe effects can also develop if you take two or more different anticholinergic drugs.

These symptoms can indicate an anticholinergic overdose known as anticholinergic syndrome, toxicity, or poisoning. Severe anticholinergic effects can include the following:

• Congestive heart failure

• Malnutrition

• Fecal impaction/paralytic ileus

• Respiratory infections

• Cardiac attack

• Urinary retention (an inability to empty your bladder completely)

• Urinary tract infection

• Ataxia

• Agitation

• Complex visual hallucinations

• Epileptic seizures

• Hyperreflexia (overactive reflex responses at your joins)

• Nocturnal rhythm disturbance (your sleep-wake rhythm is not in sync with the 24-hour day)
  

Who Might Need to Avoid Anticholinergics (When Possible)

While anticholinergics can provide a range of benefits, they may not be the best choice for the following people. However, given the condition they are used to treat, the benefits of an anticholinergic medication may outweigh the risks for each group.

Older Adults

Your body's production of acetylcholine slows with age, so using drugs that block its effects can further reduce acetylcholine levels to the point where they fail to support normal function.

Research indicates that long-term use of anticholinergics may contribute to a higher risk of cognitive decline and dementia in older adults. There is also a possible link between these drugs with falls, hospitalization, and mortality later in life.

Most drugs have a stronger effect on older people because the ability of the kidneys and liver to break down and clear drugs from your system slows with age. Hundreds of drugs in multiple drug classes have anticholinergic properties. Older people tend to take more medications for multiple conditions, putting them at risk of excessive anticholinergic effects.

Note that many people with Parkinson's disease are older adults. A healthcare provider can determine if the benefits of Parkinson's medications outweigh the risks.

People With Schizophrenia

Long-term use of anticholinergics is not advised for people with schizophrenia at any age. Over time, anticholinergics can increase cognitive impairment when used with antipsychotics (drugs used to treat schizophrenia), reducing quality of life. Research indicates that the use of anticholinergics in schizophrenia is linked with a reduction in the ability to perform cognitive tasks.

However, a healthcare provider can determine whether the benefits outweigh the risks in situations where, without these drugs, the person would need psychiatric hospitalization.

Summary

Anticholinergic drugs are among the most commonly used treatments. They block the action of a neurotransmitter called acetylcholine. This chemical messenger transfers signals between cells that affect certain body functions.

Over 600 compounds can cause this effect. This can make it complex to treat older adults, who often need more than one drug to treat multiple health problems. The added effect can raise their risk of cognitive decline and dementia. People of all ages can have effects like dry mouth and blurred vision from these drugs.

Your healthcare provider can help you decide whether using these drugs is right for you. Factors such as your age, chronic conditions, and other drugs can affect your options.

Read the original article on Verywell Health.