Cholinergic agonists are medications that stimulate cholinergic receptors, mimicking the effects of acetylcholine in the body. These drugs are crucial in treating various conditions affecting the nervous system and other body systems.
Generic names: Bethanechol, Carbachol, Pilocarpine, Methacholine
Brand names: Urecholine, Miostat, Isopto Carpine, Salagen, Provocholine
Pharmacologic class: Parasympathomimetic agents
Therapeutic class: Cholinergic stimulants
Mechanism of action: Cholinergic agonists stimulate muscarinic and nicotinic receptors, enhancing parasympathetic activity. They directly stimulate cholinergic receptors or increase acetylcholine availability at nerve endings.
Indications for use:
- Urinary retention and bladder atony
- Glaucoma
- Xerostomia (dry mouth)
- Myasthenia gravis
- Postoperative and postpartum urinary retention
- Diagnostic testing for bronchial hyperreactivity
Precautions and contraindications:
- Hypersensitivity to cholinergic medications
- Bronchial asthma
- Coronary artery disease
- Hyperthyroidism
- Peptic ulcer
- Epilepsy
- Parkinsonism
- Pregnancy and breastfeeding (evaluate risk/benefit)
Drug Interactions
- Beta-blockers may enhance bradycardic effects
- Anticholinergics antagonize therapeutic effects
- MAO inhibitors may potentiate effects
- Succinylcholine may prolong neuromuscular blockade
- Corticosteroids may decrease the effectiveness
Adverse Effects
- Cardiovascular: bradycardia, hypotension, arrhythmias
- Respiratory: bronchospasm, increased bronchial secretions
- Gastrointestinal: nausea, vomiting, diarrhea, abdominal cramps
- Ocular: miosis, blurred vision, eye pain
- Other: excessive sweating, salivation, urinary urgency
Administration Considerations
Available preparations: Tablets, ophthalmic solutions, oral solutions, and injectable forms
General dosage guidelines: Vary by specific agent and indication. Always verify current dosing guidelines and manufacturer recommendations.
Nursing Considerations for Cholinergic Agonists
Related Nursing Diagnoses
- Risk for adverse effects related to cholinergic crisis
- Risk for falls related to orthostatic hypotension
- Deficient knowledge related to medication regimen
- Risk for impaired urinary elimination
- Risk for disturbed visual sensory perception
Nursing Assessment
- Complete baseline assessment, including vital signs, especially heart rate and blood pressure
- Assess for contraindications and allergies
- Evaluate current medications for potential interactions
- Monitor respiratory status, particularly in patients with asthma
- Assess urinary patterns and bladder function
- Evaluate vision and eye health if using ophthalmic preparations
Nursing Interventions
- Monitor vital signs frequently, especially during initial therapy
- Implement fall precautions due to potential orthostatic hypotension
- Keep emergency medications available (atropine for overdose)
- Monitor intake and output carefully
- Assess for signs of cholinergic crisis (excessive secretions, bradycardia, bronchospasm)
Patient Teaching Associated with Cholinergic Agonists
Take medications exactly as prescribed; do not adjust dosage without consulting healthcare provider
Report adverse effects immediately, especially:
- Severe diarrhea or abdominal pain
- Unusual heart rate changes
- Difficulty breathing
- Severe sweating or salivation
For ophthalmic preparations:
- Proper eye drop administration technique
- Temporary blurred vision may occur
- Keep eyes clean and avoid touching the dropper tip
Lifestyle modifications:
- Change positions slowly to prevent orthostatic hypotension
- Maintain adequate hydration
- Avoid activities requiring clear vision until response to medication is established
Storage and handling:
- Store at room temperature unless otherwise directed
- Keep medications away from children
- Do not share medications with others
This is not an all-inclusive list of possible drug interactions, adverse effects, precautions, nursing considerations, or patient instructions. Please consult further with a pharmacist for complete information.
References
- Ackley, B. J., Ladwig, G. B., Makic, M. B., Martinez-Kratz, M. R., & Zanotti, M. (2020). Nursing diagnoses handbook: An evidence-based guide to planning care. St. Louis, MO: Elsevier.
- Lieberman JA, Javitch JA, Moore H. Cholinergic agonists as novel treatments for schizophrenia: the promise of rational drug development for psychiatry. Am J Psychiatry. 2008 Aug;165(8):931-6. doi: 10.1176/appi.ajp.2008.08050769. PMID: 18676593.
- Messer WS Jr. Cholinergic agonists and the treatment of Alzheimer’s disease. Curr Top Med Chem. 2002 Apr;2(4):353-8. doi: 10.2174/1568026024607553. PMID: 11966459.
- Silvestri, L. A. (2020). Saunders comprehensive review for the NCLEX-RN examination. St. Louis, MO: Elsevier.
