A patient is complaining of voiding orange coloured urine. The patient is likely to be on which of the following drugs?

Appeared in: RML 2023

Explanation

Rifampicin is a first-line antibiotic used in the treatment of tuberculosis and leprosy.
A very common and harmless side effect of Rifampicin is the discoloration of body fluids to an orange or reddish color.
This includes urine, tears, sweat, and saliva.
The color change is due to the drug's own color and its metabolic byproducts being excreted from the body.
Nurses must educate patients about this expected side effect to prevent unnecessary alarm and ensure they continue their treatment.

Option B: Oral iron supplements are known for causing gastrointestinal side effects, most notably turning stools dark green or black. They do not cause orange urine.
Option C: Nitrofurantoin is a urinary antiseptic that can discolor urine, but it typically turns it dark yellow or brown, not bright orange.
Option D: Primaquine, an antimalarial drug, can cause dark or reddish-brown urine, but this is often a sign of a serious adverse effect called hemolysis (destruction of red blood cells), particularly in patients with G6PD deficiency. It is not a benign, expected side effect.

Clinical Relevance

Nursing practice connection: Use the key finding related to Pharmacology: Drug-induced urine discoloration to guide bedside assessment, documentation, and the next nursing action.
Patient education is a critical nursing intervention. Informing patients on Rifampicin about the expected orange urine prevents non-adherence due to fear.
Nurses must be able to distinguish between harmless drug-induced color changes and pathological changes like hematuria (blood in urine) or dark urine from liver failure, which require immediate investigation.
Advise patients taking Rifampicin that soft contact lenses can be permanently stained orange, so they should consider wearing glasses during treatment.

How to Approach the Question

Identify the key clinical sign presented in the question: 'orange coloured urine'.
Recognize this as a pharmacology question that tests knowledge of common drug side effects.
Systematically review each drug option and recall its characteristic side effects.
Recall that Rifampicin is famous for causing a harmless orange-red discoloration of all body fluids.
Eliminate 'Iron' as it primarily causes black stools.
Eliminate 'Nitrofurantoin' as it typically causes brown or dark yellow urine.

Concept Tested & Keywords

Concept Tested: Pharmacology: Drug-induced urine discoloration
Stem keywords: orange coloured urine, voiding, drug
Lead-in keywords: likely to be on
Clinical cues: Orange coloured urine is a classic, harmless side effect of a specific antitubercular drug.

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E6 Nelson Textbook of Pediatrics(2024) — Volume 1 p. 1834-1836

E6 Pharmacology KD Tripathi OneStop 9e p. 148-150

Practise the full RML 2023

Attempt every question from this paper in a timed mock, then review the full solution for each one.