Ondansetron administered before chemotherapy to prevent - - RUHS, Jaipur, PB B.Sc Nursing Entrance-2024

RUHS, Jaipur, PB B.Sc Nursing Entrance-2024

Pharmacology

Easy

Appeared in: RUHS, Jaipur, PB B.Sc Nursing Entrance-2024

Explanation

Ondansetron is a selective 5-HT3 receptor antagonist, a class of drugs known as antiemetics.
It is administered before chemotherapy to prevent nausea and vomiting, a common side effect known as Chemotherapy-Induced Nausea and Vomiting (CINV).
Chemotherapy drugs trigger the release of serotonin in the gut, which stimulates the vagus nerve and the chemoreceptor trigger zone (CTZ) in the brain to induce vomiting. Ondansetron blocks this pathway at both peripheral and central sites.

Option A: Alopecia (hair loss) is caused by the cytotoxic effect of chemotherapy on rapidly dividing hair follicle cells. Ondansetron does not act on hair follicles.
Option B: Anaemia is a result of myelosuppression (bone marrow suppression) from chemotherapy, leading to decreased red blood cell production. Ondansetron does not affect hematopoiesis.
Option C: Ondansetron is not an analgesic (pain reliever). It does not have any properties that would alleviate pain.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pharmacology of Antiemetics in Chemotherapy as background academic context rather than a clinical decision trigger.
Prophylactic administration of antiemetics like Ondansetron is a cornerstone of oncology nursing. It significantly improves patient quality of life, comfort, and adherence to chemotherapy regimens by controlling CINV.
Nurses must assess the emetogenic potential of the specific chemotherapy regimen to anticipate the need for and type of antiemetic therapy. High-risk regimens require combination antiemetic therapy.
What if? If a patient experiences breakthrough vomiting despite prophylactic ondansetron, the nurse's first action is to assess the patient for dehydration and electrolyte imbalance. The nurse would then administer a prescribed 'rescue' antiemetic from a different drug class (e.g., a dopamine antagonist like prochlorperazine or a neurokinin-1 antagonist) and notify the oncologist.

How to Approach the Question

First, identify the drug mentioned in the question: Ondansetron.
Recall or look up the primary drug class and indication for Ondansetron. It is a well-known antiemetic.
Analyze the context: 'administered before chemotherapy'. This points to a prophylactic use to prevent a known side effect.
Evaluate the options, which are all potential side effects of chemotherapy: Alopecia, Anaemia, Pain, and Vomiting.
Match the drug's primary function (antiemetic/anti-vomiting) with the corresponding side effect from the options.
Confirm the match: Ondansetron is specifically used to prevent and treat nausea and vomiting. This makes 'Vomiting' the correct answer.

Concept Tested & Keywords

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