A patient has been admitted to the emergency department with a suspected overdose of a tricyclic antidepressant. The nurse will prepare for what immediate concern?

Correct Answer: C

Rationale: The correct answer is C: Cardiac dysrhythmias. Tricyclic antidepressant overdose can lead to sodium channel blockade, causing prolonged QT intervals and various cardiac arrhythmias, including ventricular tachycardia and fibrillation. This is a critical concern as it can lead to life-threatening situations like cardiac arrest. Immediate monitoring and intervention are necessary. Hypertension (A) may occur due to anticholinergic effects, but it is not the most immediate concern. Renal failure (B) and gastrointestinal bleeding (D) are not typically associated with tricyclic antidepressant overdose and are not immediate concerns in this scenario.

Correct Answer: A

Rationale: The correct answer is A: Force fluids to help loosen and liquefy secretions. Guaifenesin is an expectorant that works by thinning and loosening mucus in the airways, making it easier to cough up secretions. By instructing the patient to increase fluid intake, it helps enhance the medication's effect by keeping the secretions moist and easier to expel. Reporting clear-colored sputum (choice B) is not necessary as it is a normal sign of the medication working. Avoiding driving or operating heavy machinery (choice C) is not relevant as guaifenesin does not have sedating effects. Reporting symptoms lasting longer than 2 days (choice D) is important, but not directly related to the medication's mechanism of action.

Correct Answer: B

Rationale: The correct answer is B because absorption of drugs taken orally depends on the secretion and motor function of the gastrointestinal (GI) tract. This is because the drug needs to be properly broken down and absorbed through the GI tract before entering the bloodstream. Other choices are incorrect because: A: Fast onset of effect is more characteristic of routes like intravenous or inhalation. C: A drug reaching the blood passing the liver is more characteristic of the hepatic first-pass effect, not specific to the oral route. D: Sterilization of medicinal forms is not obligatory for the oral route, as proper storage and handling can ensure safety.

Correct Answer: B

Rationale: The correct answer is B: Cumulative effect. Continuous or repeated intake of a drug can lead to the accumulation of the drug in the body, causing a higher concentration than intended, leading to toxic reactions. Refractoriness (A) refers to decreased response to a drug over time. Tolerance (C) is the need for higher doses to achieve the same effect, not necessarily leading to toxicity. Tachyphylaxis (D) is a rapid decrease in response to a drug with repeated administration, not directly related to toxicity.

Correct Answer: D

Rationale: The correct answer is D because a vasoconstrictor actually enhances the effects of a local anesthetic by reducing its uptake by the surrounding nerves. This helps to prolong the duration of action of the anesthetic. Choices A and B are incorrect because a vasoconstrictor can retard drug removal from the injection site, which can increase the chance of toxicity. Choice C is incorrect because a vasoconstrictor actually decreases blood levels by constricting blood vessels at the site of administration, which can lead to localized effects.