From the Guidelines
Atropine is a recommended option for managing excessive secretions, particularly in end-of-life care or before procedures, due to its effectiveness in reducing secretion production in the respiratory tract. The typical dose is 0.4-0.6 mg subcutaneously or intravenously every 4-6 hours as needed, with sublingual drops (1% solution, 1-2 drops) also being an option for easier administration 1. For terminal secretions, it's often started when rattling breathing occurs and continued regularly until symptoms improve. Atropine works by blocking muscarinic acetylcholine receptors, reducing secretion production in the respiratory tract.
Some key points to consider when using atropine for managing secretions include:
- Side effects may include dry mouth, blurred vision, urinary retention, and confusion, particularly in elderly patients 1
- The medication should be used cautiously in patients with glaucoma, prostatic hypertrophy, or certain cardiac conditions 1
- Alternative anticholinergics include glycopyrrolate (0.2-0.4 mg IV/SC every 4-6 hours), which has fewer central nervous system effects, or scopolamine patches (1.5 mg applied behind the ear every 72 hours) for longer-acting control 1
It's worth noting that the most recent and highest quality study, published in 2016, supports the use of atropine for managing excessive secretions 1. While other studies, such as the one published in 2012, also discuss the use of atropine for this purpose, the 2016 study provides the most up-to-date and reliable evidence 1.
In terms of patient care, it's essential to prioritize the management of excessive secretions to improve patient comfort and quality of life, particularly in end-of-life care. Atropine, with its proven effectiveness and relatively manageable side effects, is a valuable option for clinicians to consider in these situations.
From the FDA Drug Label
Atropine is an antimuscarinic agent since it antagonizes the muscarine-like actions of acetylcholine and other choline esters. The receptors antagonized by atropine are the peripheral structures that are stimulated or inhibited by muscarine (i.e., exocrine glands and smooth and cardiac muscle).
The role of Atropine (antimuscarinic agent) in managing secretions is to inhibit the muscarinic actions of acetylcholine on exocrine glands, which includes reducing saliva flow. This is evident from the effects of intravenous atropine on saliva flow (minimum flow) after intravenous administration 2.
- Key points:
- Atropine antagonizes muscarine-like actions of acetylcholine
- Inhibits muscarinic actions on exocrine glands
- Reduces saliva flow 2
From the Research
Role of Atropine in Managing Secretions
Atropine, an antimuscarinic agent, plays a significant role in managing secretions, particularly in medical settings. The key aspects of its role are:
- Reduction of salivation and bronchial secretions prior to surgery 3
- Treatment of clozapine-induced hypersalivation, with sublingual atropine being an effective treatment option 4
- Prevention of unwanted side effects from neostigmine, such as bradycardia, when used in combination with anticholinesterase for muscle relaxant reversal 5, 6
Comparison with Other Anticholinergic Agents
Studies have compared atropine with other anticholinergic agents, such as glycopyrrolate, in terms of their effects on secretions and heart rate:
- Glycopyrrolate has been shown to be a superior oropharyngeal drying agent compared to atropine, with less initial tachycardia and a lower incidence of cardiac arrhythmias 5
- The combination of atropine and glycopyrrolate has been found to be an alternative to atropine alone for antagonizing muscarinic effects of neostigmine, with no significant difference in increase in heart rate between the two groups 6
Mechanism of Action
Atropine's mechanism of action involves binding to muscarinic receptor subtypes, with similar binding patterns to M2 (cardiac) and M3 (submandibular gland) subtypes, as shown in studies using rat ventricle and submandibular gland homogenates 7
- Atropine has been found to have high affinities for both M2 and M3 subtypes, with no selectivity for either subtype 7
Clinical Applications
Atropine's role in managing secretions has various clinical applications, including: