Lidocaine does not cause the following symptoms?

NORCET 1 - 2020

Pharmacology

Medium

Appeared in: NORCET 1 - 2020

Explanation

Constipation is the correct answer as it is not a recognized side effect of lidocaine.
Lidocaine primarily affects the cardiovascular and central nervous systems.
It lacks the significant anticholinergic effects that typically cause constipation by slowing down gastrointestinal motility.
In contrast, other antidysrhythmic drugs like disopyramide are known to cause constipation due to their atropine-like activity (SRC_4).

Option A: Hypotension is a known adverse effect of lidocaine, especially at high doses or in patients with heart failure, as it can depress myocardial contractility and relax blood vessels.
Option B: Restlessness is a classic early sign of central nervous system (CNS) toxicity from lidocaine. It is part of the initial excitatory phase.
Option D: Nausea and vomiting are recognized systemic side effects of lidocaine. The nausea is often of central origin, meaning it's caused by the drug's effect on the brain.

Visual 1: Chart: A chart listing common local anesthetics and their primary side effect profiles (CNS vs. Cardiac vs. GI).
Visual 2: Diagram: An infographic illustrating the progression of Local Anesthetic Systemic Toxicity (LAST), starting from early CNS signs like restlessness to severe cardiovascular collapse.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pharmacology: Side Effects of Lidocaine as background academic context rather than a clinical decision trigger.
Nurses must continuously monitor patients receiving lidocaine infusions for signs of toxicity, paying close attention to neurological status (restlessness, slurred speech) and vital signs (hypotension, bradycardia).
Early identification of CNS symptoms like restlessness can allow for intervention before the patient develops more severe complications like seizures or cardiovascular collapse.
What if? If the patient was receiving an opioid alongside lidocaine, constipation would be a very likely side effect, but it would be attributable to the opioid, not the lidocaine. The nurse's role would be to differentiate the cause and manage appropriately.

How to Approach the Question

First, identify the core of the question. It asks for a symptom that Lidocaine does not cause, which is a negative-style question.
Next, recall the drug class and primary systems affected by Lidocaine (a local anesthetic and antiarrhythmic). Its main effects are on the nervous system and the heart.
Review each option: Hypotension (cardiovascular), Restlessness (CNS), Nausea/Vomiting (systemic/CNS). These fit the known profile of lidocaine toxicity.
Consider the last option, Constipation. This is typically caused by drugs that slow the gut, like opioids or those with strong anticholinergic effects. Lidocaine does not primarily work this way.
Conclude that constipation is the symptom not associated with lidocaine, making it the correct answer.

Concept Tested & Keywords

Concept Tested: Pharmacology: Side Effects of Lidocaine
Stem keywords: Lidocaine, symptoms
Lead-in keywords: does not cause
Negative lead-in flag: The question asks to identify the symptom that is NOT caused by Lidocaine.

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