Which of the following drugs is LEAST effective luminal amoebicide ?
**Core Concept**
The question tests the student's knowledge of luminal amoebicides, which are drugs used to treat amoebic infections in the lumen of the intestine. **Luminal amoebicides** are crucial in the treatment of amoebiasis, targeting the cyst and trophozoite forms of the parasite in the intestinal lumen.
**Why the Correct Answer is Right**
To determine the least effective luminal amoebicide, one must consider the efficacy of each option against **Entamoeba histolytica**, the causative agent of amoebiasis. Drugs like paromomycin and diloxanide furoate are known for their effectiveness as luminal amoebicides.
**Why Each Wrong Option is Incorrect**
**Option A:** May be effective against luminal amoeba, thus not the least effective.
**Option B:** Could have some activity against the parasite, making it not the correct answer.
**Option C:** Might be used in combination with other drugs for its luminal effects.
**Clinical Pearl / High-Yield Fact**
It's crucial to remember that the treatment of amoebiasis often involves a combination of a tissue amoebicide (like metronidazole) and a luminal amoebicide to ensure both the tissue and luminal forms of the parasite are eradicated.
**Correct Answer:** D. Metronidazole.