What are anticholinergic drugs?

From the Guidelines

Anticholinergic drugs include diphenhydramine, hydroxyzine, clemastine, atropine, scopolamine, ipratropium bromide, tiotropium, glycopyrrolate, oxybutynin, tolterodine, solifenacin, darifenacin, trospium chloride, benztropine, chlorpheniramine, and tricyclic antidepressants like amitriptyline, which can have significant anticholinergic effects, particularly in elderly patients 1. These medications are used to treat various conditions, including overactive bladder, COPD, asthma, Parkinson's disease, motion sickness, and allergies.

• They work by preventing acetylcholine from binding to its receptors, which reduces smooth muscle contractions, secretions, and certain autonomic nervous system functions.
• Side effects can include dry mouth, blurred vision, constipation, urinary retention, confusion, and cognitive impairment, especially in elderly patients. The use of anticholinergic medications, particularly in older adults, should be approached with caution due to the potential for adverse effects, such as cognitive impairment, falls, and hospitalizations 1.
• It is essential to carefully evaluate the benefits and risks of anticholinergic medications in individual patients, considering factors such as age, comorbidities, and potential interactions with other medications.
• In general, it is recommended to use anticholinergic medications at the lowest effective dose and for the shortest duration necessary to minimize the risk of adverse effects 1.

From the FDA Drug Label

GLYCOPYRROLATE ORAL SOLUTION 1MG/5ML is an anticholinergic indicated to reduce chronic severe drooling in patients aged 3-16 years with neurologic conditions associated with problem drooling (e.g., cerebral palsy). Trihexyphenidyl HCl has parasympatholytic activity Benztropine mesylate possesses both anticholinergic and antihistaminic effects, although only the former have been established as therapeutically significant in the management of parkinsonism.

The anticholinergic drugs are:

• Glycopyrrolate 2
• Trihexyphenidyl 3
• Benztropine 4

From the Research

Anticholinergic Drugs

The following are examples of anticholinergic drugs:

• Atropine 5, 6, 7, 8
• Glycopyrrolate 5, 7, 8
• Scopolamine 5, 6, 7, 8
• Hyoscyamine 6

Characteristics of Anticholinergic Drugs

These drugs are:

• Competitive antagonists of acetylcholine muscarinic (M-) receptors 6
• Nonselective muscarinic receptor antagonists 5
• Used to treat various conditions, including vomiting, nausea, and bradycardia 6
• Used to reduce noisy respirations in adult hospice patients 8

Pharmacokinetics of Anticholinergic Drugs

The pharmacokinetics of these drugs vary, with:

• Atropine having a fast onset of action and a short elimination phase half-life 5, 7
• Glycopyrrolate having a slower absorption rate and a longer duration of action 5, 8
• Scopolamine being excreted mainly as inactive metabolites 5