Autonomic Nervous System

1. Autonomic Nervous System Cholinergic – Blocking Drugs

2. Cholinergic-Blocking Drugs • Describe the cholinergic-blocking drug effects on major body systems. • Discuss the nursing process in the care of patients receiving cholinergic-blocking drugs for cardiovascular, respiratory, gastrointestinal, and genitourinary system problems.

3. Cholinergic-Blocking DrugsMechanism of Action Drugs that block or inhibit the actions of acetylcholine (ACh) in the parasympathetic nervous system (PSNS) • anticholinergics • Compete with Ach & block ACh at the muscarinic receptors in the PSNS • ACh is unable to bind to the receptor site and cause a cholinergic effect Once these drugs bind to receptors, they inhibit nerve transmission at these receptors

4. Cholinergic-Blocking Drugs

5. Cholinergic-Blocking DrugsChemical Class Natural Synthetic/ Semisynthetic atropinebenztropine (Cogentin) Belladonnadicyclomine (Bentyl) glycopyrrolate Robinul) Hyoscyamine homatropine ipratropium Scopolamine isopropamide methscopolamine oxybutynin (Ditropan) propantheline tolterodine (Detrol) solifenacin (Vesicare)

6. Cholinergic-Blocking DrugsDrugs • Atropine – preop; bradycardia; • Dicyclomine (Bentyl) – irritable bowel syndrome • glycopyrrolate (Robinul) – intraop to control secretions; PUD (peptic ulcer disease), reversal of neuromuscular blockers • Oxybutynin (Ditropan) – antispasmodic for neurogenic bladder; overactive bladder; spinal cord injury • Scopolamine (Transderm-Scop) – control of secretions; motion sickness • Tolterodine (Detrol) – overactive bladder

7. Cholinergic-Blocking DrugsDrug Effects • Cardiovascular • Small doses: decrease heart rate • Large doses: increase heart rate • CNS • Small doses: decrease muscle rigidity and tremors • Large doses: drowsiness, disorientation, hallucinations • Respiratory • Decreased bronchial secretions • Dilated bronchial airways

8. Cholinergic-Blocking DrugsDrug Effects • Eye • Dilated pupils (mydriasis) • Decreased accommodation due to paralysis of ciliary muscles (cycloplegia) • Gastrointestinal • Relax smooth muscle tone of GI tract • Decrease intestinal and gastric secretions • Decrease motility and peristalsis

9. Cholinergic-Blocking DrugsDrug Effects • Genitourinary • Relaxed detrusor muscle • Increased constriction of internal sphincter • Result: urinary retention • Glandular • Decreased bronchial secretions, salivation, sweating

10. Cholinergic-Blocking DrugsIndications - CNS • To decrease muscle rigidity and muscle tremors • Parkinson’s disease • Drug-induced extrapyramidal reactions

11. Cholinergic-Blocking DrugsIndications - Cardiovascular Affect the heart’s conduction system • Low doses: slow the heart rate • Appropiate doses: block inhibitory vagal effects on the SA and AV node pacemaker cells • Intended Effect: increased heart rate • Uses: • Diagnosis of sinus node dysfunction • Symptomatic second-degree heart block • Severe sinus bradycardia with hemodynamic compromise (advanced life support)

12. Cholinergic-Blocking DrugsIndications – Respiratory • Blocking the cholinergic stimulation of the PSNS allows unopposed action of the SNS • Results • Decreased secretions from nose, mouth, pharynx, bronchi • Relaxed smooth muscles in bronchi and bronchioles • Bronchodilation • Decreased airway resistance

13. Cholinergic-Blocking DrugsIndications - Respiratory Respiratory drugs are used to treat: • Exercise-induced bronchospasms • Chronic bronchitis • Asthma • Chronic obstructive pulmonary disease

14. Cholinergic-Blocking DrugsIndications - Gastrointestinal • PSNS controls gastric secretions and smooth muscles that produce gastric motility • Blockade of PSNS results in: • Decreased secretions • Relaxation of smooth muscle • Decreased GI motility and peristalsis Gastrointestinal drugs are used to treat: • Irritable bowel disease • GI hypersecretory states • Acute pancreatitis (reduces gastric and pancreatic secretions)

15. Cholinergic-Blocking DrugsIndications - Genitourinary • Reflex neurogenic bladder • Incontinence

16. Cholinergic-Blocking DrugsOther Indications Preoperatively to reduce salivary secretions

17. Cholinergic-Blocking DrugsAdverse Effects Body SystemAdverse Effects Cardiovascular Increased heart rate, dysrhythmias CNS Excitation, restlessness, irritability, disorientation, hallucinations, delirium Eye Dilated pupils, decreased visual accommodation, increased intraocular pressure GastrointestinalDecreased salivation, decreased gastric secretions, decreased motility Genitourinary Urinary retention Glandular Decreased sweating Respiratory Decreased bronchial secretions

18. Cholinergic-Blocking DrugsInteractions • Antihistamines • phenothiazines • tricyclic antidepressants • MAOIs • When given with cholinergic blocking drugs, cause additive effects, resulting in increased effects

19. Cholinergic-Blocking DrugsNursing Implications • These drugs will block the action of ACh in the PSNS • Assess for allergies, presence of BPH, glaucoma, tachycardia, MI, HF, hiatal hernia, and GI or GU obstruction • Perform baseline assessment of vital signs and systems overview • Medications should be taken exactly as prescribed to have the maximum therapeutic effect • Overdosing can cause life-threatening problems • Blurred vision may cause problems with driving or operating machinery

20. Cholinergic-Blocking DrugsNursing Implications • Patients may experience sensitivity to light – sun glasses • When giving ophthalmic solutions, apply pressure to the inner canthus to prevent systemic absorption • Dry mouth may occur: chewing gum, frequent mouth care, and hard candy • Check with physician before taking any other medication, including OTC medications • Antidote for atropine overdose is physostigmine

21. Cholinergic-Blocking DrugsNursing Implications – Patient Ed • Anticholinergics taken by the elderly patient may lead to higher risk for heatstroke due to effects on heat-regulating mechanisms • Teach patients to limit physical exertion and avoid high temperatures and strenuous exercise • Emphasize the importance of adequate fluid and salt intake

22. Cholinergic-Blocking DrugsPatient Education Patients should report the following to their physician: • Urinary hesitancy and/or retention • Constipation • Palpitations • Tremors, confusion, sedation or amnesia, • Excessive dry mouth • especially if pt. chronic lung infections or disease • Fever

23. Cholinergic-Blocking DrugsNursing Implications Monitor for therapeutic effects • For patients with Parkinson’s disease: fewer tremors and decreased salivation and drooling • For urologic problems: improved urinary patterns, less hypermotility, increased time between voiding Monitor for adverse effects