Cholinergic Antagonists Overview Unit 4.4

Cholinergic Antagonists (Anticholinergics)

• Cholinergic antagonists, also called anticholinergics or cholinergic blockers, act opposite to cholinergic agonists.
• They inhibit the action of acetylcholine.
• They increase heart rate.
• They cause bronchodilation and reduce secretions.
• They decrease gastrointestinal (GI) motility and peristalsis, reducing GI secretions.
• They increase bladder sphincter constriction.
• They dilate pupils.
• They decrease salivation and perspiration.
• They decrease tremors and rigidity.

Anticholinergics - Atropine

• Action: Non-selective; inhibits acetylcholine by occupying receptors; increases heart rate by blocking vagal nerve stimulation.

• Uses: Decreasing salivation and respiratory/GI secretions before surgery; increasing heart rate in bradycardia; dilating pupils for eye exams.

• Side effects/Adverse reactions: Dry mouth and skin; inability to sweat; flushing; blurred vision; constipation; urinary retention; palpitations; hypertension.

Anticholinergic Antiparkinson's - Benztropine

• Action: Blocks acetylcholine in skeletal muscles; blocks dopamine reuptake, allowing longer dopamine activity.

• Uses: Decreasing involuntary muscle movement, tremors, and rigidity; Parkinson's disease; pseudoparkinsonism.

• Side effects/Adverse reactions: Symptoms very similar to atropine.

• Contraindications: Glaucoma; tardive dyskinesia; myasthenia gravis; psychosis.

• Interactions: Other anticholinergic drugs; drugs increasing heart rate and blood pressure.

Anticholinergic - Tolterodine Tartrate

• Action: Selectively blocks cholinergic receptors in the bladder.

• Uses: Overactive bladder; decreasing urinary frequency, urgency, and incontinence.

• Side effects/Adverse reactions: Similar to atropine.

• Contraindications: Similar to atropine.

• Interactions: Grapefruit juice can increase drug levels.

Anticholinergic Drug Assessment

• Assessment: Vital signs; medication/medical history; reason for medication; urine output.

Anticholinergic Drug Interventions

• Interventions: Monitor vital signs (especially for tachycardia); monitor intake and output (for urinary retention); monitor bowel status (for constipation); provide mouth care; dilute intravenous atropine in sterile water and administer slowly (at least 1 mg/minute).

Teaching Clients about Anticholinergic Drugs

• Teach the client to: Avoid hot environments; increase fluid and fiber intake; report decreased urine output; use hard candy for dry mouth; practice good oral care; wear sunglasses; avoid driving until understanding the drug effects (which may cause drowsiness).

Anticholinergic Drug Evaluation

• Evaluation: Important to understand why the nurse gave the medication and if it's having the desired effect (therapeutic effect).
• Atropine: Evaluate if heart rate increased if bradycardic before surgery; evaluate if there are dry mouth complaints.
• Benztropine: Evaluate for decreased involuntary movement.
• Tolterodine Tartrate: Evaluate for decreased bladder irritability and fewer trips to the bathroom with balanced intake and output.