The nurse reviewing a patient’s preoperative medications noted that atropine sulfate was listed. In which diagnoses should atropine sulfate be used with caution? Select all that apply

Tacrine (Cognex) is a cholinesterase inhibitor used in the treatment of Alzheimer’s disease. It increases acetylcholine levels in the brain to enhance memory and cognition. However, excessive cholinergic stimulation from overdose can lead to signs of cholinergic toxicity, which nurses and caregivers must closely monitor.

Rationale for correct answer:

1. Excessive sweating, salivation, and drooling
These are hallmark signs of cholinergic toxicity. Tacrine increases parasympathetic activity, and an overdose may lead to excessive secretions, bradycardia, muscle weakness, and in severe cases, respiratory compromise.

Rationale for incorrect answer:

2. Extreme constipation
Constipation is more typical of anticholinergic toxicity, not cholinergic excess. Tacrine enhances cholinergic activity, which usually increases GI motility rather than slowing it down.

3. Hypertension and tachycardia
These are signs more often associated with sympathetic nervous system overactivity, not with cholinergic overstimulation caused by drugs like tacrine.

4. Excessively dry eyes and reddened sclera
Dry eyes are an anticholinergic effect. Tacrine, being a cholinergic agent, would more likely cause increased lacrimation (tear production), not dryness.

Take-home points:

• Tacrine overdose manifests with signs of cholinergic excess, including sweating, salivation, drooling, and bradycardia.
• Cholinergic drugs increase parasympathetic activity; caregivers should know the early signs of overdose to act promptly.
• Differentiating between cholinergic and anticholinergic effects is essential for safe medication management in Alzheimer’s care.

Atenolol (Tenormin) is a cardioselective beta-1 blocker prescribed for hypertension, angina, and cardiac arrhythmias. Nurses must evaluate potential drug interactions that could reduce atenolol’s effectiveness or amplify its adverse effects, especially those that affect heart rate, blood pressure, or renal perfusion.

Rationale for correct answers:

2. An NSAID, such as aspirin – NSAIDs can reduce the antihypertensive effects of beta-blockers like atenolol by inhibiting renal prostaglandins, potentially increasing blood pressure.

3. Atropine, an anticholinergic – Atropine increases heart rate by blocking parasympathetic input, which may counteract atenolol’s beta-blocking effect, potentially complicating heart rate control.

Rationale for incorrect answers:

1. Ginseng supplement – While ginseng may have mild cardiovascular effects, it has not been shown to consistently interfere with atenolol. It is not a well-documented interaction.

4. Haloperidol (Haldol) – Although both drugs may prolong the QT interval, there is no direct, frequent interaction reported between haloperidol and atenolol affecting the drug's main mechanism.

5. Methyldopa (Aldomet) – Both methyldopa and atenolol lower blood pressure, but they are sometimes used together. Their additive effect is monitored, but this is not considered a strong or dangerous interaction.

Take-home points:

• NSAIDs can blunt the antihypertensive effect of beta-blockers like atenolol.
• Atropine may reduce atenolol's therapeutic effect by increasing heart rate.
• Always evaluate over-the-counter medications or supplements for potential cardiovascular interactions.