Anticholinergic (Cholinergic Blocking) Agents

Adapted from PDR - Nurse's Handbook (1999)
Typical anticholinergic (cholinergic blocking) agents include (but are not limited to) the following:

Action/Kinetics:

Anticholinergic (cholinergic blocking) agents prevent the neurotransmitter acetylcholine from combining with receptors on the postganglionic parasympathetic nerve terminal (muscarinic site). Effects include reduction of smooth muscle spasms, blockade of vagal impulses to the heart, decreased secretions (e.g., gastric, salivation, bronchial mucus, sweat glands), production of mydriasis and cycloplegia, and various CNS effects. In therapeutic doses, these drugs have little effect on transmission of nerve impulses across ganglia (nicotinic sites) or at the neuromuscular junction. Several anticholinergic drugs abolish or reduce the symptoms of Parkinson's disease, such as tremors and rigidity, and result in sonic improvement in mobility, muscular coordination, and motor performance. These effects may be due to blockade of the effects of acetylcholine in the CNS.


Uses:

See individual drugs.


Contralndicatlons:

Glaucoma, adhesions between iris and lens of the eye, tachycardia, myocardial ischemia, unstable CV state in acute hemorrhage, partial obstruction of the GI and biliary tracts, prostatic hypertrophy, renal disease, myasthenia gravis, hepatic disease, paralytic ileus, pyloroduodenal stenosis, pyloric obstruction, intestinal atony, ulcerative colitis, obstructive uropathy. Cardiac clients, especially when there is danger of tachycardia; older persons suffering from atherosclerosis or mental impairment. Lactation.


Special Concerns:

Use with caution in pregnancy. Infants and young children are more susceptible to the toxic side effects of anticholinergic drugs. Use in children when the ambient temperature is high may cause a rapid increase in body temperature due to suppression of sweat glands. Geriatric clients are particularly likely to manifest anticholinergic side effects and CNS effects, including agitation, confusion, drowsiness, excitement, glaucoma, and impaired memory. Use with caution in hyperthyroidism, CHF, cardiac arrhythmias, hypertension, Down syndrome, asthma, spastic paralysis, blonde individuals, allergies, and chronic lung disease.


Side Effects:

These are desirable in some conditions and undesirable in others. Thus, the anticholinergics have an antisalivary effect that is useful in parkinsonism. This same effect is unpleasant when the drug is used for spastic conditions of the GI tract. Most side effects are dose-related and decrease when dosage decreases.

GI: dry mouth, dysphagia, constipation, heartburn, change in taste perception, bloated feeling, paralytic ileus.

CNS: Dizziness, drowsiness, nervousness, disorientation, headache, weakness, insomnia, fever (especially in children). Large doses may produce CNS stimulation including tremor and restlessness. Anticholinergic psychoses: ataxia, euphoria, confusion, disorientation, loss of shortterm memory, decreased anxiety, fatigue, insomnia, hallucinations, dysarthria, agitation.

CV: Palpitations.

GU: Urinary retention or hesitancy, impotence.

Ophthalmologic: Blurred vision, dilated pupils, photophobia, cycloplegia, precipitation of acute glaucoma.

Allergic: Urticaria, skin rashes, anaphylaxis

Other: Flushing, decreased sweating, nasal congestion, suppression of glandular secretions including lactation. Heat prostration (fever and heat stroke)in presence of high environmental temperatures due to decreased sweating.


Overdose Management:

Symptoms ("Belladonna Poisoning"): Infants and children are especially susceptible to the toxic effects of atropine and scopolamine. Poisoning (dose-dependent) is characterized by the following symptoms: dry mouth, burning sensation of the mouth, difficulty in swallowing and speaking, blurred vision, photophobia, rash, tachycardia, increased respiration, increased body temperature, restlessness, irritability, confusion, muscle incoordination, dilated pupils, hot dry skin, respiratory depression and paralysis, tremors, seizures, hallucinations. and death.

Treatment ("Belladonna Poisoning"):

Drug interactions
Dosage

See individual drugs.

Nursing Considerations:

Administration/Storage: Dosage is often small. To prevent overdosage, check dosage and measure the drug exactly.

Assessment
  1. Document indications for therapy; assess for asthma, glaucoma, or duodenal ulcer (contraindications for therapy).
  2. Note history of renal disease, cardiac problems, or hepatic disease.
  3. Determine age; elderly clients, especially those with mental impairment or atherosclerosis, should not receive these drugs.
  4. Assess for constipation and urinary retention and tolerance.

Interventions
  1. If the client complains of a dry mouth, provide frequent mouth care and cold drinks, especially postoperatively. Sugarless hard candies and chewing gum may also be of some benefit.
  2. Drugs such as atropine may suppress thermoregulatory sweating; counsel client concerning activity (especially in hot weather) and appropriate clothing. Also, children and infants may exhibit "atropine fever."
Client/Family Teaching
  1. Certain side effects are to be expected, such as dry mouth or blurred vision, and may have to be tolerated because of the overall beneficial effects of drug therapy. These should he reported so symptoms may he alleviated by reducing the dose on by temporarily stopping the drug.
  2. With parkinsonism, do not withdraw abruptly. If the medication is changed, one drug should he withdrawn slowly and the other started in small doses.

Additional Nursing Considerations Related to Pathological Conditions for which the Drug is Administered

Cardiovascular
Interventions
  1. Monitor VS and ECG. Assess for any hemodynamic changes and intraventricular conduction blocks.
  2. Note any complaints of palpitations.
Ocular
Assessment
  1. Determine any previous experience with this class of drugs and the results.
  2. Document IOP and assess accommodation and pupillary response.
Interventions
  1. Note complaints of dizziness or blurred vision; assist with ambulalion and institute safety measures.
  2. Hold meds and report any complaints of eye pain after instillation.
Client/Family Teaching
  1. Review methods for instillation of drops or ointment.
  2. Vision will be affected by the meds; temporary stinging and blurred vision will occur. Assess response and plan activities for safety.
  3. Night vision may be impaired. Photophobia, which may occur, can be relieved by wearing dark glasses.
  4. Report any marked changes in vision, eye irritation, or persistent headaches immediately.
  5. With large doses, lacrimal secretion may be diminished; may experience dry or "sandy" eyes.
Gastrointestinal
Client/Family Teaching
  1. Take early enough before a meal (at least 20 min) so that it will be effective when needed.
  2. Review printed information related to the prescribed diet; see dietitian for assistance in meal planning and preparation as needed.
  3. Gastric emptying times may he prolonged and intestinal transit time lengthened. Drug-induced intestinal paralysis is temporary and should resolve after 1-3 days of therapy.
Genitourinary
Interventions
  1. Assess middle-aged male clients for evidence of urinary retention; may be more pronounced in elderly men with prostatic hypertrophy.
  2. Monitor input and output. Palpate abdomen for evidence of bladder distention and assess need for catheterization.
  3. Consult with the provider for medication adjustment if impotence occurs; may be drug-related.
Outcomes/Evaluate


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Document last modified:08/15/08 10:43:25 AM