UPPSC 2022: For the treatment of head lice commonly used

UPPSC 2022

Pharmacology

Easy

Appeared in: UPPSC 2022

Explanation

5% Malathion is an organophosphate cholinesterase inhibitor specifically formulated as a lotion for treating pediculosis (head lice).
It is effective because it has both pediculicidal (kills live lice) and ovicidal (kills eggs/nits) properties.
The mechanism of action involves irreversible inhibition of the cholinesterase enzyme in lice, leading to nerve paralysis and death.
It is often considered a treatment of choice, particularly in areas where lice have developed resistance to other agents like permethrin.

Option B: Terpentine (turpentine) oil is a toxic, volatile solvent derived from pine resin. It is not approved for medical use on the skin and can cause severe chemical burns, irritation, and systemic toxicity if absorbed.
Option C: Formaldehyde is a preservative and disinfectant, classified as a known human carcinogen. It is extremely hazardous to apply to the skin and is never used to treat lice due to its high toxicity.
Option D: Hydrogen peroxide is a mild antiseptic and bleaching agent. It does not possess effective pediculicidal (lice-killing) or ovicidal (egg-killing) properties and is therefore not an effective treatment for a head lice infestation.

Clinical Relevance

Nursing practice connection: Knowing Pharmacological treatment for pediculosis capitis (head lice) helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Nurses play a key role in educating patients and families on the correct application of pediculicides, emphasizing safety precautions like avoiding open flames as malathion lotion is flammable.
A crucial nursing intervention is teaching meticulous nit combing after treatment to remove dead lice and eggs, which prevents misdiagnosis of treatment failure and reduces re-infestation risk.
Environmental control, such as washing bedding and clothing in hot water and sealing non-washable items in plastic bags for two weeks, is essential to prevent the spread and re-infestation of lice.

How to Approach the Question

This is a factual recall question asking for a common pharmacological treatment for a specific condition.
First, identify the condition mentioned in the stem: head lice (pediculosis capitis).
Next, systematically evaluate each option based on your knowledge of pharmacology and dermatology treatments.
Recognize that malathion is an organophosphate insecticide formulated for medical use against ectoparasites.
Eliminate the other options by identifying them as inappropriate or dangerous substances for topical application on the scalp: Terpentine oil (toxic solvent), Formaldehyde (carcinogenic preservative), and Hydrogen peroxide (ineffective antiseptic).
Select the option that is a known and approved pediculicide.

Concept Tested & Keywords

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E6 Pharmacology Katzung 16e p. 1671-1673

E6 Nelson Textbook of Pediatrics(2024) — Volume 2 p. 1985-1987

E6 Nelson Textbook of Pediatrics(2024) — Volume 1 p. 2140-2142