All of the following drugs cause urine discoloration except?

RUHS, Jaipur, M.Sc Nursing Entrance Exam-2021

Pharmacology

Easy

Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2021

Explanation

Digoxin is a cardiac glycoside primarily used to manage heart failure and atrial fibrillation.
It does not have urine discoloration as a recognized side effect.
The classic signs of Digoxin toxicity include gastrointestinal issues (nausea, vomiting), cardiac arrhythmias, and neurological symptoms, most notably visual disturbances like seeing yellow-green halos around objects.

Option A: Nitrofurantoin, an antibiotic commonly prescribed for urinary tract infections (UTIs), is known to cause urine to turn brown or rust-yellow.
Option B: Rifampicin, a key antibiotic in the treatment of tuberculosis, famously causes a harmless red-orange discoloration of most body fluids, including urine, sweat, tears, and saliva.
Option D: Phenazopyridine is an over-the-counter urinary tract analgesic used to relieve symptoms like pain and burning. It is an azo dye that causes a characteristic bright orange or red discoloration of the urine.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pharmacology: Drug Side Effects (Urine Discoloration) as background academic context rather than a clinical decision trigger.
Patient education is crucial. Nurses must inform patients about expected, harmless urine color changes from drugs like rifampicin or phenazopyridine to prevent anxiety and non-adherence.
Advise patients taking rifampicin that soft contact lenses can be permanently stained red-orange, so they should consider wearing glasses during treatment.
What if? If a patient on warfarin reports red or dark brown urine, it's a critical finding. Unlike the harmless discoloration from rifampicin, this could indicate hematuria (blood in urine) due to excessive anticoagulation and requires immediate investigation and reporting to the provider.

How to Approach the Question

First, identify the core of the question: it's asking about the side effect profiles of different drugs.
Note the keyword 'except'. This signals that three of the options share a common characteristic (causing urine discoloration), and your task is to find the one that does not.
Systematically review the common and distinctive side effects of each drug listed.
Recall that Nitrofurantoin, Rifampicin, and Phenazopyridine are all well-known for causing noticeable changes in urine color.
Contrast this with Digoxin, whose toxicity profile is classically associated with cardiac, gastrointestinal, and visual disturbances (like yellow halos), not urine discoloration. This contrast identifies Digoxin as the correct exception.

Concept Tested & Keywords

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E6 Pharmacology KD Tripathi Essentials 9e Part 3 p. 88-90